CN101539480B

CN101539480B - One-dimensional evaluation method of combustion efficiency for scramjet engine

Info

Publication number: CN101539480B
Application number: CN2009100719324A
Authority: CN
Inventors: 鲍文; 李文静; 崔涛
Original assignee: Harbin Institute of Technology Shenzhen
Current assignee: Harbin Institute of Technology Shenzhen
Priority date: 2009-04-30
Filing date: 2009-04-30
Publication date: 2011-05-11
Anticipated expiration: 2029-04-30
Also published as: CN101539480A

Abstract

超燃冲压发动机的燃烧效率的一维评价方法，它涉及一种发动机的燃烧效率的评价方法。本方法实现对燃烧工况经济性能的快速评估；并扩大现有一维评价方法的适用范围并使之具有普适性。本方法的主要步骤为：确定入口条件及压力分布、给出燃烧效率初值η₀、确定燃烧室截面各成分质量分数g、确定燃烧室某一截面处的静温T_kc、求出燃烧混合物焓值H_kc及平均分子量μ_kc、求出燃烧室截面当地声速a及马赫数M、确定燃烧室壁面摩擦系数c_f及沿流动方向耗散力X_o、求出燃烧混合物流速w、燃烧室壁面单位热流q_w、燃烧效率η的计算值、判断燃烧效率与初值是否相同。应用本方法可以对超声速燃烧效率及相关热动和气动参数进行快速分析，并最终得到燃烧效率及相关参数沿燃烧室轴向的一维分布规律。The invention discloses a one-dimensional evaluation method for the combustion efficiency of a scramjet engine, which relates to an evaluation method for the combustion efficiency of an engine. The method realizes the rapid evaluation of the economic performance of the combustion working condition; and expands the scope of application of the existing one-dimensional evaluation method and makes it universal. The main steps of this method are: determine the inlet conditions and pressure distribution, give the initial value of combustion efficiency η ₀ , determine the mass fraction g of each component in the combustion chamber section, determine the static temperature T _kc at a certain section of the combustion chamber, and calculate the combustion mixture Enthalpy value H _kc and average molecular weight μ _kc , calculate the local sound velocity a and Mach number M of the combustion chamber section, determine the friction coefficient c _f of the combustion chamber wall and the dissipation force X _o along the flow direction, calculate the flow velocity w of the combustion mixture, and the combustion chamber The unit heat flow q _w of the wall surface, the calculated value of the combustion efficiency η, and the judgment whether the combustion efficiency is the same as the initial value. The method can be used to quickly analyze supersonic combustion efficiency and related thermal and aerodynamic parameters, and finally obtain the one-dimensional distribution law of combustion efficiency and related parameters along the axial direction of the combustion chamber.

Description

One-Dimensional Evaluation Method of Scramjet Combustion Efficiency

技术领域technical field

本发明涉及一种发动机的燃烧效率的评价方法，具体涉及一种超燃冲压发动机燃烧室燃烧效率的一维评价方法。The invention relates to a method for evaluating the combustion efficiency of an engine, in particular to a one-dimensional evaluation method for the combustion efficiency of a combustion chamber of a scramjet engine.

背景技术Background technique

目前超燃冲压发动机的三种研发手段分别为地面试验、飞行试验和数值模拟。地面试验是最基本手段，须具备模拟实际飞行条件下来流组分、总压、总温和速度的能力，对实验设备、模拟方法、测量技术、数据处理等要求较高；飞行试验成本巨大，需要完善的地面保障系统，作为最后的验证手段；数值模拟提供整个流场的详细流动特性，但机时长，计算收敛性依赖于计算条件，完全的数值模拟难以实现。一维评价方法克服以上困难，可实现对试验结果的快捷分析。At present, the three research and development methods of scramjet are ground test, flight test and numerical simulation. The ground test is the most basic method, which must have the ability to simulate the downflow components, total pressure, total temperature and velocity under actual flight conditions, and has high requirements for experimental equipment, simulation methods, measurement techniques, data processing, etc.; the cost of flight tests is huge, requiring A complete ground support system is used as the final verification method; numerical simulation provides detailed flow characteristics of the entire flow field, but the computer time is long, and calculation convergence depends on calculation conditions, and complete numerical simulation is difficult to achieve. The one-dimensional evaluation method overcomes the above difficulties and can realize the quick analysis of the test results.

燃烧效率作为评价发动机性能的重要指标，经多年研究已发展多套评价方法。目前各方法在应用范围、适用条件及准确度方面均无统一标准，实际应用中存在较大不确定性。由于存在自身的局限性，实际应用中需要多种评价方法相互补充，相互发展，不断完善。工程中，一维方法往往忽略了一些本来存在的因素，一定程度上限制了方法的普适性。总结起来，以往方法中存在以下限定假设：燃烧混气作为理想均一气体处理，比热和比热比取为常数；忽略壁面摩擦及吸热作用；不考虑燃料注入对工质流量、动量及能量变化的影响。燃烧室中真实工况复杂多变，并不严格遵守某种或几种假设，因此根据实际情况，结合试验测量数据，突破以上限定实现燃烧效率的评判具有实际应用意义。研究的目的是扩大一维评价方法的适用范围，并设法使之具有普适性。Combustion efficiency is an important indicator for evaluating engine performance, and many sets of evaluation methods have been developed after years of research. At present, there is no unified standard for each method in terms of application range, applicable conditions and accuracy, and there are great uncertainties in practical application. Due to its own limitations, multiple evaluation methods need to complement each other, develop each other and improve continuously in practical application. In engineering, one-dimensional methods often ignore some existing factors, which limits the universality of the method to a certain extent. To sum up, there are the following limiting assumptions in the previous methods: the combustion mixture is treated as an ideal homogeneous gas, and the specific heat and specific heat ratio are taken as constants; the wall friction and heat absorption are ignored; impact of change. The real working conditions in the combustion chamber are complex and changeable, and one or several assumptions are not strictly followed. Therefore, according to the actual situation, combined with the experimental measurement data, it is of practical application significance to break through the above limitations and realize the evaluation of combustion efficiency. The purpose of the research is to expand the scope of application of the one-dimensional evaluation method and try to make it universal.

燃烧效率不能直接测量，需要通过测量得到一些参数后经处理换算求出。实验中比较可靠的测量数据是壁面压强、天平数据和热流数据(尽管热流测量精度稍差)。求解一维流动方程组时，若燃烧室型面确定，壁面静压、热流分布已知，则影响燃烧效率的因素将包括混气沿程的平均分子量、定压比热和壁面摩擦力。一维评价方法应用于强燃烧工况，在气流相对均匀的流场部分(燃烧室后部)具有相当的可信度。Combustion efficiency cannot be measured directly, and some parameters need to be obtained through measurement and then processed and converted to obtain it. The more reliable measurement data in the experiment are wall pressure, balance data and heat flow data (although the accuracy of heat flow measurement is slightly worse). When solving one-dimensional flow equations, if the profile of the combustion chamber is determined and the static pressure and heat flow distribution on the wall are known, the factors affecting the combustion efficiency will include the average molecular weight, specific heat at constant pressure and wall friction along the mixture. The one-dimensional evaluation method is applied to strong combustion conditions, and has considerable reliability in the part of the flow field where the airflow is relatively uniform (the rear of the combustion chamber).

发明内容Contents of the invention

本发明的目的是提供一种超燃冲压发动机的燃烧效率的一维评价方法，利用该方法可以快速得到燃烧过程中的燃烧效率及相关热动和气动参数的分布规律，从而实现对燃烧工况经济性能的快速评估；并扩大现有一维评价方法的适用范围并使之具有普适性。The purpose of the present invention is to provide a one-dimensional evaluation method for the combustion efficiency of a scramjet, by which the combustion efficiency in the combustion process and the distribution law of related thermodynamic and aerodynamic parameters can be obtained quickly, so as to realize the evaluation of combustion conditions Rapid evaluation of economic performance; and expand the scope of application of the existing one-dimensional evaluation method and make it universal.

本发明的技术方案是：本发明所述的超燃冲压发动机的燃烧效率的一维评价方法是按照以下步骤实现的：The technical scheme of the present invention is: the one-dimensional evaluation method of the combustion efficiency of the scramjet engine described in the present invention is realized according to the following steps:

步骤一、确定燃烧室入口条件及压力分布：通过试验或者数值模拟得到超燃冲压发动机燃烧室壁面压力分布情况，根据物性分析软件ASPEN建立燃烧室中各组分的分子量及焓值数据库，建立分子量及焓值与压力、温度及氧化剂过氧系数的函数关系μ(p，T，α)及H(p，T，α)；已知燃烧室入口总质量流量和各成分所占分数，确定G_τ、G_o、L_oτ、α、

和I_BX，利用燃烧效率与各组分质量分数间的相互转化，联立动量方程、能量方程、流量方程和气体状态方程构成的基本方程组耦合求解，上述四个基本方程如(1)至(4)式所示：Step 1. Determine the inlet conditions and pressure distribution of the combustion chamber: Obtain the pressure distribution of the scramjet combustion chamber wall through experiments or numerical simulations, and establish the molecular weight and enthalpy database of each component in the combustion chamber according to the physical property analysis software ASPEN, and establish the molecular weight And the functional relationship between enthalpy value and pressure, temperature and oxidant peroxygen coefficient μ (p, T, α) and H (p, T, α); given the total mass flow rate of the combustion chamber inlet and the fraction of each component, determine G _τ , G _o , L _oτ , α,

and I _BX , using the mutual conversion between combustion efficiency and the mass fraction of each component, the basic equations composed of simultaneous momentum equation, energy equation, flow equation and gas state equation are coupled and solved. The above four basic equations are as (1) to (4) as shown in the formula:

${I I}_{BX BX} + + \underset{{F f}_{σok σok}}{&Integral; &Integral;} {p p}_{kc kc} d d \overset{&RightArrow; &Right Arrow;}{F f} - - {X x}_{o o} = = {I I}_{kc kc} = = {G G}_{Σ Σ} {w w}_{kc kc} + + {p p}_{kc kc} {F f}_{kc kc} - - - - - - ((11))$

${H h}_{BX BX}^{* *} - - \frac{Q Q}{{G G}_{Σ Σ}} = = {g g}_{τkc τkc} {H h}_{τ τ} (({p p}_{τkc τkc},, {T T}_{kc kc},, α α = = 00)) + + {g g}_{okc okc} {H h}_{o o} (({p p}_{okc okc},, {T T}_{kc kc},, α α = = \infty \infty)) + + {g g}_{nckc nckc} {H h}_{nc nc} (({p p}_{nckc nckc},, {T T}_{kc kc},, α α = = 11)) + + \frac{{w w}_{}^{kc kc}}{22} - - - - - - ((22))$

${ρ ρ}_{BX BX} {w w}_{BX BX} = = \frac{{αL α L}_{oτ oτ}}{11 + + {αL α L}_{oτ oτ}} {ρ ρ}_{kc kc} {w w}_{kc kc} {\overset{&OverBar; &OverBar;}{F f}}_{kc kc} - - - - - - ((33))$

${p p}_{kc kc} = = {ρ ρ}_{kc kc} \frac{R R}{{μ μ}_{kc kc}} {T T}_{kc kc} - - - - - - ((44))$

其中，I为冲量；X_o为燃烧室沿流动方向耗散力；G_∑为总工质质量流量；F为面积，为相对截面积，H(p，T，α)为比焓函数，特别

为燃烧室入口总比焓；Q为燃烧室壁面热流；g为质量分数；μ(p，T，α)为分子量函数；L_oτ为氧化剂对燃料的化学当量系数；α为氧化剂过氧系数G_τ和G_o分别为实际给定的燃料和氧化剂质量流量；w为燃烧室内工质流速；R为通用气体常数；ρ为工质密度；T表示静温；Among them, I is the impulse; X _o is the dissipation force of the combustion chamber along the flow direction; G _∑ is the mass flow rate of the total working medium; F is the area, is the relative cross-sectional area, H(p, T, α) is the specific enthalpy function, especially

is the total specific enthalpy at the entrance of the combustion chamber; Q is the heat flow on the wall of the combustion chamber; g is the mass fraction; μ(p, T, α) is the molecular weight function; L _oτ is the chemical equivalent coefficient of the oxidant to the fuel; G _τ and G _o are the actual given mass flow rate of fuel and oxidant respectively; w is the flow rate of the working medium in the combustion chamber; R is the universal gas constant; ρ is the density of the working medium; T is the static temperature;

其中，对下脚标的解释：“kc”表示燃烧室某一截面处，“BX”表示入口截面处，“σok”表示燃烧室侧壁面，“τ”表示燃料层，“o”表示氧化剂层，“nc”表示燃烧产物层；脚标“τkc”表示燃烧室某一截面处燃料层，变量“μ_kc”表示燃烧混合物平均分子量，F_kc为燃烧室某一截面处横截面积；Among them, the explanation of the subscript: "kc" indicates a certain section of the combustion chamber, "BX" indicates the inlet section, "σok" indicates the side wall of the combustion chamber, "τ" indicates the fuel layer, "o" indicates the oxidant layer, "nc" indicates the combustion product layer; the subscript "τkc" indicates the fuel layer at a certain section of the combustion chamber, the variable "μ _kc " indicates the average molecular weight of the combustion mixture, and F _kc is the cross-sectional area at a certain section of the combustion chamber;

步骤二、给出燃烧效率初值η₀：Step 2. Give the initial value of combustion efficiency η ₀ :

$η η = = \frac{{η η}_{npak npak}}{{η η}_{meop meop}} = = \frac{{G G}_{τcz τcz}}{{\overset{&OverBar; &OverBar;}{G G}}_{τ τ}} = = \frac{{G G}_{ocz ocz}}{{\overset{&OverBar; &OverBar;}{G G}}_{o o}} - - - - - - ((55))$

步骤三、确定燃烧室截面各成分质量分数g：Step 3. Determine the mass fraction g of each component in the combustion chamber section:

${g g}_{τkc τkc} = = \frac{{G G}_{τ τ} - - {G G}_{τcz τcz}}{{G G}_{Σ Σ}} = = {g g}_{τ τ} ((11 - - {η η}_{00} {α α}^{v v})) - - - - - - ((66))$

${g g}_{okc okc} = = \frac{{G G}_{o o} - - {G G}_{ocz ocz}}{{G G}_{Σ Σ}} = = {g g}_{o o} ((11 - - {η η}_{00} {α α}^{v v - - 11})) - - - - - - ((77))$

${g g}_{nckc nckc} = = \frac{{G G}_{τcz τcz} + + {G G}_{ocz ocz}}{{G G}_{Σ Σ}} = = {η η}_{00} (({g g}_{τ τ} {α α}^{v v} + + {g g}_{o o} {α α}^{v v - - 11})) - - - - - - ((88))$

$\frac{11}{{μ μ}_{kc kc}} = = \frac{{g g}_{τkc τkc}}{{μ μ}_{τkc τkc} (({p p}_{τkc τkc},, {T T}_{kc kc},, α α = = 00))} + + \frac{{g g}_{okc okc}}{{μ μ}_{okc okc} (({p p}_{okc okc},, {T T}_{kc kc},, α α = = \infty \infty))} + + \frac{{g g}_{nckc nckc}}{{μ μ}_{nckc nckc} (({p p}_{nckc nckc},, {T T}_{kc kc},, α α = = 11))} - - - - - - ((99))$

其中，η_npak为实际反应效率；η_meop为理论反应效率；η为燃烧效率；

和

分别为燃料完全燃烧时，理论上应反应完的燃料和氧化剂质量流量；G_τcz和G_ocz分别为实际反应完的燃料与氧化剂质量流量；v为计算系数，规定α≤1，v＝1；α≥1，v＝0；Wherein, η _npak is actual reaction efficiency; η _meop is theoretical reaction efficiency; η is combustion efficiency;

and

are respectively the mass flow rates of fuel and oxidant that should be reacted theoretically when the fuel is completely combusted; G _τcz and G _ocz are the mass flow rates of fuel and oxidant that are actually reacted respectively; α≥1, v=0;

步骤四、确定燃烧室某一截面处的静温：结合气体状态方程(4)式及(9)式确定燃烧室某一截面处的静温T_kc；Step 4, determine the static temperature at a certain section of the combustion chamber: determine the static temperature T _kc at a certain section of the combustion chamber in conjunction with the gas state equation (4) and (9);

步骤五、求出燃烧混合物焓值及平均分子量μ_kc：Step five, calculate the enthalpy value and average molecular weight μ _kc of the combustion mixture:

结合物性分析软件ASPEN得出燃烧混合物焓值及入口燃烧混合物平均分子量；Combined with the physical property analysis software ASPEN to obtain the enthalpy of the combustion mixture and the average molecular weight of the combustion mixture at the entrance;

步骤六、求出燃烧室截面当地声速a及马赫数M：Step 6. Calculate the local sound velocity a and the Mach number M of the combustion chamber section:

结合动量方程(1)式、流量方程(3)式求出燃烧室截面当地声速及马赫数；Combining the momentum equation (1) and the flow equation (3) to obtain the local sound velocity and Mach number of the combustion chamber section;

步骤七、确定燃烧室壁面摩擦系数c_f及沿流动方向耗散力X_o：Step 7. Determine the friction coefficient c _f of the combustion chamber wall and the dissipation force X _o along the flow direction:

结合动量方程(1)式、流量方程(3)式得出燃烧室壁面摩擦系数及沿流动方向耗散力；Combining the momentum equation (1) and the flow equation (3), the friction coefficient of the combustion chamber wall and the dissipation force along the flow direction are obtained;

步骤八、求出燃烧混合物流速w：Step 8. Find the flow rate w of the combustion mixture:

步骤九、求出燃烧室壁面单位热流q_w：Step 9. Calculate the unit heat flow q _w on the wall surface of the combustion chamber:

步骤十、求出燃烧效率η的计算值：Step ten, obtain the calculated value of combustion efficiency η:

结合能量方程(2)式及(6)至(8)式，得到燃烧效率计算式(24)式：Combining the energy equation (2) and (6) to (8), the combustion efficiency calculation formula (24) is obtained:

$η η = = \frac{{H h}_{BX BX}^{* *} - - \frac{Q Q}{{G G}_{Σ Σ}} - - {g g}_{o o} {H h}_{o o} (({p p}_{okc okc},, {T T}_{kc kc},, α α = = \infty \infty)) - - {g g}_{τ τ} {H h}_{τ τ} (({p p}_{τkc τkc},, {T T}_{kc kc},, α α = = 00)) - - \frac{{w w}_{}^{kc kc}}{22}}{(({g g}_{o o} {α α}^{v v - - 11} + + {g g}_{τ τ} {α α}^{v v})) {H h}_{nc nc} (({p p}_{nckc nckc},, {T T}_{kc kc},, α α = = 11)) - - {g g}_{o o} {α α}^{v v - - 11} {H h}_{o o} (({p p}_{okc okc},, {T T}_{kc kc},, α α - - \infty \infty)) - - {g g}_{τ τ} {α α}^{v v} {H h}_{τ τ} (({p p}_{τkc τkc},, {T T}_{kc kc},, α α = = 00))} - - - - - - ((24 twenty four))$

其中燃烧室壁面热流计算采用雷诺近似法：The heat flow calculation on the combustion chamber wall adopts the Reynolds approximation method:

$Q Q = = \underset{{F f}_{σok σok}}{&Integral; &Integral;} {q q}_{w w} {dF f}_{σok σok} - - - - - - ((2525))$

${q q}_{w w} = = \frac{{c c}_{f f}}{22} {ρ ρ}_{kc kc} {w w}_{kc kc} S S ((I I)) (({H h}_{r r} - - {H h}_{w w})) - - - - - - ((2626))$

$S S ((I I)) = = \frac{{22 q q}_{w w}}{{c c}_{f f} {ρ ρ}_{kc kc} {w w}_{kc kc} (({H h}_{r r} - - {H h}_{w w}))} - - - - - - ((2727))$

${H h}_{r r} = = {H h}_{kc kc} + + r r \frac{{w w}_{kc kc}^{22}}{22} - - - - - - ((2828))$

其中，S(I)为雷诺相似参数；H_r为恢复焓；H_w为壁面气体焓；q_w为燃烧室壁面单位热流；Among them, S(I) is the Reynolds similarity parameter; H _r is the recovery enthalpy; H _w is the wall gas enthalpy; q _w is the unit heat flow of the combustion chamber wall;

步骤十一、判断燃烧效率与初值是否相同：Step 11. Determine whether the combustion efficiency is the same as the initial value:

比较η与给定初值η₀是否相同，如果是，则执行步骤十二；否则回到步骤二，循环迭代，直至得到满足精度要求的燃烧效率η的计算值；Compare whether η is identical with given initial value η ₀ , if yes, then perform step 12; Otherwise, get back to step 2, loop iteratively, until obtaining the calculated value of the combustion efficiency η that satisfies the precision requirement;

步骤十二、结束。Step twelve, end.

本发明的有益效果是：应用本方法可以对燃烧效率及相关热动和气动参数进行快速分析，并最终得到燃烧效率及相关参数沿燃烧室轴向的一维分布规律。本方法引入燃烧混气的真实组分进行计算，并根据燃烧过程的实际情况考虑壁面摩擦，壁面热流，燃料质量添加的影响；与已有一维方法相比，在实际燃烧工况的基础上拓宽了方法的适用范围，从而实现对燃烧过程经济性能的快速评估。该方法首先得到超燃冲压发动机燃烧试验数据或者仿真数据，将燃烧室壁面压力作为计算模型的已知参数；考虑燃烧室实际燃气组分将计算模型分为燃料层、氧化剂层和燃烧产物层；然后应用一维流动方程组结合模型分层计算求解；最终得到超声速燃烧过程中燃烧效率及热动、气动参数的变化情况。The beneficial effects of the present invention are: the method can be used to quickly analyze the combustion efficiency and related thermal and aerodynamic parameters, and finally obtain the one-dimensional distribution law of the combustion efficiency and related parameters along the axial direction of the combustion chamber. This method introduces the real components of the combustion mixture for calculation, and considers the influence of wall friction, wall heat flow, and fuel mass addition according to the actual situation of the combustion process; compared with the existing one-dimensional method, it expands on the basis of actual combustion conditions The scope of application of the method is clarified, so as to realize the rapid evaluation of the economic performance of the combustion process. This method first obtains the combustion test data or simulation data of the scramjet engine, and uses the wall pressure of the combustion chamber as a known parameter of the calculation model; considering the actual gas composition of the combustion chamber, the calculation model is divided into a fuel layer, an oxidant layer and a combustion product layer; Then apply one-dimensional flow equations combined with model layered calculation to solve; finally get the combustion efficiency and the changes of thermal and aerodynamic parameters in the process of supersonic combustion.

附图说明Description of drawings

图1为本方法超燃冲压发动机燃烧效率计算流程框图，图2为超燃冲压发动机燃烧效率一维评价方法的各参数计算思路框图，图3为试验用燃烧室结构示意图(燃烧室的长度单位为英尺；1为燃料喷射器，2为冷却水套，3为动作筒)，图4为燃烧室中氢-空气燃烧试验的压力测量值图(横坐标为燃烧室的长度，单位为米；纵坐标为压力值，单位为Mpa)，图5a为马赫数沿室长分布曲线图与平均拟合值图(横坐标为燃烧室的长度，单位为米，纵坐标为马赫数值；带有方块的实线为曲线图，没带有方块的实线为拟合值图)，图5b为静温沿室长分布曲线图与平均拟合值图(横坐标为燃烧室的长度，单位为米，纵坐标为静温值，单位为开尔文；带有方块的实线为曲线图，没带有方块的实线为拟合值图)，图5c为燃烧混合物平均分子量沿室长分布曲线图与平均拟合值图(横坐标为燃烧室的长度，单位为米；纵坐标为燃烧混合物平均分子量；这里计算结果为相对分子量，单位为1)；带有方块的实线为曲线图，没带有方块的实线为拟合值图)，图5d为燃烧效率沿室长分布曲线图与平均拟合值图(横坐标为燃烧室的长度，单位为米；纵坐标为燃烧效率；带有方块的实线为曲线图，没带有方块的实线为拟合值图)。Fig. 1 is a block diagram of the scramjet combustion efficiency calculation process of this method, Fig. 2 is a block diagram of the calculation ideas of each parameter of the scramjet combustion efficiency one-dimensional evaluation method, and Fig. 3 is a schematic diagram of the combustion chamber structure for the test (the length unit of the combustion chamber 1 is a fuel injector, 2 is a cooling water jacket, and 3 is an action cylinder), and Fig. 4 is the pressure measurement value figure of the hydrogen-air combustion test in the combustion chamber (the abscissa is the length of the combustion chamber, and the unit is meter; The ordinate is the pressure value, and the unit is Mpa), and Fig. 5a is the Mach number along the chamber length distribution curve and the average fitting value figure (the abscissa is the length of the combustion chamber, and the unit is meter, and the ordinate is the Mach value; with square The solid line is the graph, the solid line without squares is the fitted value graph), and Fig. 5b is the static temperature distribution curve along the chamber length and the average fitted value graph (the abscissa is the length of the combustion chamber, and the unit is meter , the ordinate is the static temperature value, and the unit is Kelvin; the solid line with squares is the graph, and the solid line without squares is the fitted value graph), and Fig. 5c is the distribution curve and the average molecular weight of the combustion mixture along the length of the chamber Average fitted value diagram (the abscissa is the length of the combustion chamber, the unit is meter; the ordinate is the average molecular weight of the combustion mixture; the calculated result here is the relative molecular weight, the unit is 1); the solid line with squares is the graph, without The solid line with block is the fitted value figure), and Fig. 5d is the distribution curve and the average fitted value figure of the combustion efficiency along the length of the chamber (the abscissa is the length of the combustion chamber, in meters; the ordinate is the combustion efficiency; with The solid line with squares is the graph, and the solid line without squares is the fitted value graph).

具体实施方式Detailed ways

具体实施方式一：如图1所示，本实施方式所述的超燃冲压发动机的燃烧效率的一维评价方法是按照以下步骤实现的：Specific embodiment one: as shown in Figure 1, the one-dimensional evaluation method of the combustion efficiency of the scramjet described in this embodiment is realized according to the following steps:

步骤一、确定燃烧室入口条件及压力分布：通过试验或者数值模拟得到超燃冲压发动机燃烧室壁面压力分布情况，根据物性分析软件(例如ASPEN)建立燃烧室中各组分的分子量及焓值数据库，建立分子量及焓值与压力、温度及氧化剂过氧系数的函数关系μ(p，T，α)及H(p，T，α)；已知燃烧室入口总质量流量和各成分所占分数，确定G_τ、G_o、L_oτ、α、

和I_BX，利用燃烧效率与各组分质量分数间的相互转化，联立动量方程(S12)、能量方程(S04)、流量方程(S08)和气体状态方程(S09)构成的基本方程组耦合求解，上述四个基本方程如(1)至(4)式所示：Step 1. Determine the inlet conditions and pressure distribution of the combustion chamber: Obtain the pressure distribution of the scramjet combustion chamber wall through experiments or numerical simulations, and establish the molecular weight and enthalpy database of each component in the combustion chamber according to the physical property analysis software (such as ASPEN) , establish the functional relationship between molecular weight and enthalpy value and pressure, temperature and oxidant peroxygen coefficient μ(p, T, α) and H(p, T, α); the total mass flow rate and the fraction of each component at the combustion chamber inlet are known , determine G _τ , G _o , L _oτ , α,

and I _BX , using the mutual conversion between combustion efficiency and the mass fraction of each component, the basic equations composed of simultaneous momentum equation (S12), energy equation (S04), flow equation (S08) and gas state equation (S09) are coupled Solving, the above four basic equations are shown in formulas (1) to (4):

${ρ ρ}_{BX BX} {w w}_{BX BX} = = \frac{{αL α L}_{oτ oτ}}{11 + + {αL αL}_{oτ oτ}} {ρ ρ}_{kc kc} {w w}_{kc kc} {\overset{&OverBar; &OverBar;}{F f}}_{kc kc} - - - - - - ((33))$

为燃烧室入口总比焓；Q为燃烧室壁面热流；g为质量分数；μ(p，T，α)为分子量函数；L_oτ为氧化剂对燃料的化学当量系数；α为氧化剂过氧系数

G_τ和G_o分别为实际给定的燃料和氧化剂质量流量；w为燃烧室内工质流速；R为通用气体常数；ρ为工质密度；T表示静温(燃烧室混合物静温)；Among them, I is the impulse; X _o is the dissipation force of the combustion chamber along the flow direction; G _∑ is the mass flow rate of the total working medium; F is the area, is the relative cross-sectional area, H(p, T, α) is the specific enthalpy function, especially

is the total specific enthalpy at the entrance of the combustion chamber; Q is the heat flow on the wall of the combustion chamber; g is the mass fraction; μ(p, T, α) is the molecular weight function; L _oτ is the chemical equivalent coefficient of the oxidant to the fuel;

G _τ and G _o are the actual given mass flow rate of fuel and oxidant respectively; w is the flow rate of the working medium in the combustion chamber; R is the general gas constant; ρ is the density of the working medium; T represents the static temperature (static temperature of the mixture in the combustion chamber);

和

and

结合物性分析软件ASPEN得出燃烧混合物焓值及入口燃烧混合物平均分子量；Combined with the property analysis software ASPEN to obtain the enthalpy value of the combustion mixture and the average molecular weight of the combustion mixture at the entrance;

$η η = = \frac{{H h}_{BX BX}^{* *} - - \frac{Q Q}{{G G}_{Σ Σ}} - - {g g}_{o o} {H h}_{o o} (({p p}_{okc okc},, {T T}_{kc kc},, α α = = \infty \infty)) - - {g g}_{τ τ} {H h}_{τ τ} (({p p}_{τkc τkc},, {T T}_{kc kc},, α α = = 00)) - - \frac{{w w}_{}^{kc kc}}{22}}{(({g g}_{o o} {α α}^{v v - - 11} + + {g g}_{τ τ} {α α}^{v v})) {H h}_{nc nc} (({p p}_{nckc nckc},, {T T}_{kc kc},, α α = = 11)) - - {g g}_{o o} {α α}^{v v - - 11} {H h}_{o o} (({p p}_{okc okc},, {T T}_{kc kc},, α α = = \infty \infty)) - - {g g}_{τ τ} {α α}^{v v} {H h}_{τ τ} (({p p}_{τkc τkc},, {T T}_{kc kc},, α α = = 00))} - - - - - - ((24 twenty four))$

${H h}_{r r} = = {H h}_{kc kc} + + r r {w w}_{} \frac{{kc kc}_{22}}{22} - - - - - - ((2828))$

步骤十二、结束。Step twelve, end.

具体实施方式二：本实施方式中在步骤六中，燃烧室截面当地声速及马赫数计算采用平衡离解气体法：Specific implementation mode two: In step six in this embodiment mode, the equilibrium dissociated gas method is used for calculating the local sound velocity and Mach number of the combustion chamber section:

H_kc＝g_τkcH_τ(p_τkc，T_kc，α＝0)+g_okcH_o(p_okc，T_kc，α＝∞)+g_nckcH_nc(p_nckc，T_kc，α＝1)(10)H _kc = g _τkc H _τ (p _τkc , T _kc , α=0)+g _okc H _o (p _okc , T _kc , α=∞)+g _nckc H _nc (p _nckc , T _kc , α=1) (10)

${c c}_{p p} = = {((\frac{{&PartialD; &PartialD; H h}_{kc kc}}{{&PartialD; &PartialD; T T}_{kc kc}}))}_{{p p}_{kc kc}} - - - - - - ((1111))$

${c c}_{v v} = = {c c}_{p p} - - \frac{{R R [[11 - - {((\frac{{&PartialD; &PartialD; ln ln μ μ}_{kc kc}}{{&PartialD; &PartialD; ln ln T T}_{kc kc}}))}_{{p p}_{kc kc}}]]}^{22}}{{μ μ}_{kc kc} [[11 + + {((\frac{{&PartialD; &PartialD; ln ln μ μ}_{kc kc}}{{&PartialD; &PartialD; ln ln p p}_{kc kc}}))}_{{T T}_{kc kc}}]]} - - - - - - ((1212))$

$k k = = \frac{{c c}_{p p}}{{c c}_{v v}} - - - - - - ((1313))$

${a a}_{kc kc} = = \sqrt{\frac{{kRT kR}_{kc kc}}{{μ μ}_{kc kc} [[11 + + {((\frac{{&PartialD; &PartialD; ln ln μ μ}_{kc kc}}{{&PartialD; &PartialD; ln ln p p}_{kc kc}}))}_{{T T}_{kc kc}}]]}} - - - - - - ((1414))$

M_kc＝w_kc/a_kc(15)M _kc ＝w _kc /a _kc (15)

其中，H_kc为燃烧室某一截面处燃烧混和物比焓；c_p为定压比热；c_v为定容比热；k为比热比；M为马赫数；a为当地声速。Among them, H _kc is the specific enthalpy of the combustion mixture at a certain section of the combustion chamber; c _p is the specific heat at constant pressure; c _v is the specific heat at constant volume; k is the specific heat ratio; M is the Mach number; a is the local sound velocity.

具体实施方式三：本实施方式在步骤七中，所述燃烧室壁面摩擦损失采用平板无梯度紊流边界层半经验公式：Specific implementation mode three: In step seven of this implementation mode, the friction loss on the wall surface of the combustion chamber adopts the semi-empirical formula of the flat plate non-gradient turbulent boundary layer:

$\frac{0.242 0.242 \sqrt{11 - - ω ω - - β β}}{\sqrt{{c c}_{f f}} \sqrt{β β}} [[arcsin arcsin \frac{\sqrt{β β} + + \frac{ω ω}{22 \sqrt{β β}}}{\sqrt{11 + + \frac{{ω ω}^{22}}{44 β β}}} - - arcsin arcsin \frac{\frac{ω ω}{22 \sqrt{β β}}}{\sqrt{11 + + \frac{{ω ω}^{22}}{44 β β}}}]] = = 0.41 0.41 + + lg lg (({R R}_{ex ex} {c c}_{f f})) - - lg lg ((\frac{{μ μ}_{w w}}{{μ μ}_{e e}})) - - - - - - ((1616))$

$β β = = r r \frac{k k - - 11}{22} {M m}_{kc kc}^{22} \frac{{T T}_{kc kc}}{{T T}_{w w}} - - - - - - ((1717))$

${T T}_{r r} = = {T T}_{kc kc} ((11 + + r r \frac{k k - - 11}{22} {M m}_{kc kc}^{22})) - - - - - - ((1818))$

$ω ω = = 11 - - \frac{{T T}_{r r}}{{T T}_{w w}} - - - - - - ((1919))$

$\frac{{μ μ}_{w w}}{{μ μ}_{e e}} = = {((\frac{{T T}_{w w}}{{T T}_{kc kc}}))}^{n no} - - - - - - ((2020))$

${X x}_{mp mp} = = \underset{{F f}_{σok σok}}{&Integral; &Integral;} \frac{11}{22} {c c}_{f f} {ρ ρ}_{kc kc} {w w}_{kc kc}^{22} {dF f}_{σok σok} - - - - - - ((21 twenty one))$

X_o＝X_n+X_mp(22)X _o =X _n +X _mp (22)

${p p}_{BX BX} + + {ρ ρ}_{BX BX} {w w}_{} {BX BX}_{22} + + \frac{{p p}_{BX BX} + + {p p}_{kc kc}}{22} (({\overset{&OverBar; &OverBar;}{F f}}_{kc kc} - - 11)) - - {X x}_{o o} / / {F f}_{BX BX} = = {\overset{&OverBar; &OverBar;}{F f}}_{kc kc} (({p p}_{kc kc} + + {ρ ρ}_{kc kc} {w w}_{kc kc}^{22})) - - - - - - ((23 twenty three))$

其中，ω和β为计算过程中间量；T_r为恢复温度，r为恢复系数；T_w为燃烧室壁面温度；R_ex为当前坐标下的雷诺数；c_f为壁面摩擦系数；x_n为燃油支板气动阻力(可由冷态进气试验测定)；X_mp为燃烧室壁面摩擦力；

为近壁面动力黏度与外部气流动力黏度之比，n为指数，n可由试验测定。Among them, ω and β are the intermediate quantities in the calculation process; T _r is the recovery temperature, r is the recovery coefficient; T _w is the wall temperature of the combustion chamber; R _ex is the Reynolds number under the current coordinates; c _f is the friction coefficient of the wall; x _n is The aerodynamic resistance of the fuel support plate (can be determined by the cold air intake test); X _mp is the friction force of the combustion chamber wall;

is the ratio of the dynamic viscosity near the wall to the dynamic viscosity of the external airflow, n is an index, and n can be determined by experiments.

实施例：参见图1～5d所示，本发明提出的超燃冲压发动机的燃烧效率的一维评价方法，其各计算思路如图1所示。为得到沿室长方向的参数分布情况，将燃烧室沿室长方向选取适当计算长度进行分段计算，每一段的参数计算情况如下：Embodiment: Referring to Figs. 1-5d, the one-dimensional evaluation method for the combustion efficiency of a scramjet proposed by the present invention, and its calculation ideas are shown in Fig. 1 . In order to obtain the distribution of parameters along the length of the chamber, the combustion chamber is calculated in segments along the length of the chamber by selecting an appropriate calculation length. The calculation of the parameters of each segment is as follows:

1、通过试验或者数值模拟得到超燃冲压发动机燃烧室壁面压力分布情况，根据物性分析软件(ASPEN)建立燃烧室中各组分的分子量(S01)及焓值(S02)数据库，建立分子量及焓值与压力、温度及混合物组成的函数关系μ(p，T，α)及H(p，T，α)(各物理量意义如下述)；1. Obtain the pressure distribution of the combustion chamber wall of the scramjet engine through experiments or numerical simulations, and establish the molecular weight (S01) and enthalpy value (S02) database of each component in the combustion chamber according to the physical property analysis software (ASPEN), and establish the molecular weight and enthalpy The functional relationship between the value and the pressure, temperature and mixture composition μ (p, T, α) and H (p, T, α) (the meaning of each physical quantity is as follows);

2、已知燃烧室入口总质量流量和各成分所占分数(由此可确定G_τ，G_o，L_oτ，α，I_BX，各物理量意义如下所述)，利用燃烧效率与各组分质量百分比间的相互转化，联立动量方程(S12)、能量方程(S04)、流量方程(S08)和气体状态方程(S09)(分别为(1)至(4)式)构成的基本方程组耦合求解，基本方程如下示：2. The total mass flow rate at the inlet of the combustion chamber and the fractions of each component are known (G _τ , G _o , L _oτ , α, I _BX , the meanings of each physical quantity are as follows), using the mutual transformation between the combustion efficiency and the mass percentage of each component, the simultaneous momentum equation (S12), energy equation (S04), flow equation (S08) and gas state equation (S09 ) (respectively (1) to (4) equations) to solve the coupling solution of the basic equations, the basic equations are as follows:

其中，I为冲量；X_o为燃烧室沿流动方向耗散力；G_∑为总质量流量；F为面积，

为相对截面积，H(p，T，α)为比焓函数，特别

为燃烧室入口总比焓(分段计算中为根据上一段计算所得热动参数，计算得到的该段入口总比焓)；Q为燃烧室壁面热流；g为质量分数；μ(p，T，α)为分子量函数；L_oτ为氧化剂对燃料的化学当量系数；α为氧化剂过氧系数，

G_τ和G_o分别为实际给定的燃料和氧化剂质量流量；w为燃烧室内工质流速；R为通用气体常数；ρ为工质密度；T表示静温(燃烧室混合物静温)；其中，对脚标的解释：“kc”表示燃烧室某一截面处，“BX”表示入口截面处，“σok”表示侧壁，“τ”表示燃料层，“o”表示氧化剂层，“nc”表示燃烧产物层，例如脚标“τkc”表示燃烧室某一截面处燃料层，变量“μ_kc”表示燃烧混合物平均分子量，F_kc为燃烧室某一截面处横截面积；Among them, I is the impulse; X _o is the dissipation force of the combustion chamber along the flow direction; G _∑ is the total mass flow rate; F is the area,

is the relative cross-sectional area, H(p, T, α) is the specific enthalpy function, especially

is the total specific enthalpy at the entrance of the combustion chamber (in the segmental calculation, it is based on the thermodynamic parameters calculated in the previous section, and the total specific enthalpy at the entrance of this section is calculated); Q is the heat flow on the wall of the combustion chamber; g is the mass fraction; μ(p, T , α) is the molecular weight function; L _oτ is the stoichiometric coefficient of the oxidant to the fuel; α is the peroxygen coefficient of the oxidant,

G _τ and G _o are the actual given mass flow rates of fuel and oxidant, respectively; w is the flow rate of the working medium in the combustion chamber; R is the universal gas constant; ρ is the density of the working medium; T represents the static temperature (static temperature of the mixture in the combustion chamber); , the explanation of the subscripts: "kc" indicates a section of the combustion chamber, "BX" indicates the inlet section, "σok" indicates the side wall, "τ" indicates the fuel layer, "o" indicates the oxidant layer, and "nc" indicates The combustion product layer, for example, the subscript "τkc" indicates the fuel layer at a certain section of the combustion chamber, the variable " _μkc " indicates the average molecular weight of the combustion mixture, and F _kc is the cross-sectional area at a certain section of the combustion chamber;

计算得到燃烧效率及相关热动和气动参数，计算流程如图1和图2所示：The combustion efficiency and related thermal and aerodynamic parameters are calculated, and the calculation process is shown in Figure 1 and Figure 2:

(a)、给出燃烧效率初值η₀(燃烧效率定义如式(5))，确定燃烧室截面各成分质量分数((6)至(8)式)(S03)。结合气体状态方程((4)式)(S09)及(9)式，确定入口燃烧混合物平均分子量(S05)及燃烧混合物温度；(a), given the initial value of combustion efficiency η ₀ (combustion efficiency is defined as formula (5)), determine the mass fraction of each component in the combustion chamber section ((6) to (8) formula) (S03). Combining the gas state equation ((4) formula) (S09) and (9) formula, determine the inlet combustion mixture average molecular weight (S05) and combustion mixture temperature;

其中，η_npak为实际反应效率；η_meop为理论反应效率；η为燃烧完全系数定义的计算燃烧效率；和

分别为燃料完全燃烧时，理论上应反应完的燃料和氧化剂质量流量；G_τcz和G_ocz分别为实际反应完的燃料与氧化剂质量流量；v为计算系数，规定α≤1，v＝1；α≥1，v＝0；Wherein, η _npak is the actual reaction efficiency; η _meop is the theoretical reaction efficiency; η is the calculated combustion efficiency defined by the combustion complete coefficient; and

(b)、结合动量方程((1)式)(S12)，流量方程((3)式)(S08)，燃烧室截面当地声速(S07)和马赫数(S10)计算式((10)至(15)式)及燃烧室壁面摩擦计算式((16)至(23)式)得到燃烧室混合物流速及燃烧室壁面摩擦系数(S11)；(b), in conjunction with the momentum equation ((1) formula) (S12), flow equation ((3) formula) (S08), the local sound velocity (S07) and Mach number (S10) calculation formula of the combustion chamber section ((10) to (15) formula) and combustion chamber wall friction calculation formula ((16) to (23) formula) obtain combustion chamber mixture flow rate and combustion chamber wall surface friction coefficient (S11);

(I)、燃烧室截面当地声速及马赫数计算采用平衡离解气体法：(1), the calculation of the local sound velocity and Mach number of the combustion chamber section adopts the equilibrium dissociated gas method:

$k k = = \frac{{c c}_{p p}}{{c c}_{v v}} - - - - - - ((1313))$

M_kc＝w_kc/a_kc(15)M _kc ＝w _kc /a _kc (15)

其中，H_kc为燃烧室某一截面处燃烧混和物比焓；c_p为定压比热；c_v为定容比热；k为比热比；M为马赫数；a为当地声速；各脚标含义如前述。Among them, H _kc is the specific enthalpy of the combustion mixture at a certain section of the combustion chamber; c _p is the specific heat at constant pressure; c _v is the specific heat at constant volume; k is the specific heat ratio; M is the Mach number; a is the local sound velocity; The meanings of the subscripts are as mentioned above.

(II)、燃烧室壁面摩擦损失采用平板无梯度紊流边界层的半经验公式：(II) The friction loss of the combustion chamber wall adopts the semi-empirical formula of the boundary layer of flat plate without gradient turbulence:

$ω ω = = 11 - - \frac{{T T}_{r r}}{{T T}_{w w}} - - - - - - ((1919))$

${X x}_{mp mp} = = \underset{{F f}_{σok σok}}{&Integral; &Integral;} \frac{11}{22} {c c}_{f f} {ρ ρ}_{kc kc} {w w}_{kc kc}^{22} d d {F f}_{σok σok} - - - - - - ((21 twenty one))$

X_o＝X_n+X_mp (22)X _o =X _n +X _mp (22)

其中，ω和β为计算过程中间量；T_r为恢复温度，r为恢复系数；T_w为燃烧室壁面温度；R_ex为当前坐标下的雷诺数；c_f为壁面摩擦系数；X_n为燃油支板气动阻力(可由冷态进气试验测定)；X_mp为燃烧室壁面摩擦力；为近壁面动力黏度与外部气流动力黏度之比，n为指数(可由试验测定)；Among them, ω and β are intermediate quantities in the calculation process; T _r is the recovery temperature, r is the recovery coefficient; T _w is the wall temperature of the combustion chamber; R _ex is the Reynolds number under the current coordinates; c _f is the friction coefficient of the wall; X _n is The aerodynamic resistance of the fuel support plate (can be determined by the cold air intake test); X _mp is the friction force of the combustion chamber wall; is the ratio of the dynamic viscosity near the wall to the dynamic viscosity of the external airflow, n is an index (can be determined by experiment);

(c)、结合能量方程((2)式)(S04)及(6)至(8)式，得到燃烧效率计算式((24)式)，比较给定初值η₀，循环迭代，至得到满足精度要求的燃烧效率数值η：(c), combined with the energy equation ((2) formula) (S04) and (6) to (8) formula, obtain the combustion efficiency calculation formula ((24) formula), compare the given initial value η ₀ , loop iteratively, to Obtain the combustion efficiency value η that meets the accuracy requirements:

其中燃烧室壁面热流(S13)计算采用雷诺近似法：The heat flow (S13) on the combustion chamber wall is calculated using the Reynolds approximation method:

其中，S(I)为雷诺相似参数；H_r为恢复焓；H_w为壁面气体焓；q_w为燃烧室壁面单位热流。Among them, S(I) is the Reynolds similarity parameter; H _r is the recovery enthalpy; H _w is the wall gas enthalpy; q _w is the unit heat flow of the combustion chamber wall.

通过各计算模块循环迭代求解，最终可以得到满足计算精度的燃烧室内工质的燃烧效率、总温、马赫数及各成分质量分数等参数，并通过分段计算，选取适当计算长度，可以得到各所求参数沿室长的分布情况。Through cyclic and iterative solutions of each calculation module, parameters such as combustion efficiency, total temperature, Mach number, and mass fraction of each component in the combustion chamber that meet the calculation accuracy can be finally obtained. Find the distribution of the parameters along the length of the chamber.

3、计算结果利用燃烧室内混合物各组分或热动、气动参数进行验证，由数值模拟值或实验测量值与模型计算值进行比较。采用试验装置为前部带有面积扩压管的超燃冲压发动机燃烧室，其由燃料喷射器、冷却水套、动作筒、试验段及测量装置组成，试验用燃烧室结构示意图如图3。其中，燃烧室入口面积0.0038m²，出口截面积0.0076m²，采用氢为燃料，化学当量系数L_or＝34.2。氢燃料由声速喷嘴喷出，质量流量21.1g/s；燃烧室入口来流为纯空气，质量流量1.4458kg/s。燃烧室中氢-空气燃烧试验的压力测量值如图4所示。用实验测量值(见表1)验证如图5，且由于一维评价方法应用于强燃烧工况，因此选取气流相对均匀的流场部分(燃烧室后部)验证具有相当的可信度。采用本方法，计算得到的出口截面燃烧效率值与已知测量值比较，相对误差为0.38％；温度相对误差为0.91％；马赫数相对误差为0.18％。3. The calculation results are verified by using the components of the mixture in the combustion chamber or the thermal and aerodynamic parameters, and the numerical simulation values or experimental measurement values are compared with the model calculation values. The test device used is a scramjet combustion chamber with an area diffuser at the front, which is composed of a fuel injector, a cooling water jacket, an action cylinder, a test section and a measuring device. The structure diagram of the combustion chamber for the test is shown in Figure 3. Among them, the inlet area of the combustion chamber is 0.0038m ² , the outlet cross-sectional area is 0.0076m ² , hydrogen is used as fuel, and the stoichiometric coefficient L _or =34.2. The hydrogen fuel is ejected from the sonic nozzle with a mass flow rate of 21.1g/s; the incoming flow from the combustion chamber inlet is pure air with a mass flow rate of 1.4458kg/s. The pressure measurements of the hydrogen-air combustion test in the combustion chamber are shown in Fig. 4. The experimental measurement values (see Table 1) are used to verify as shown in Figure 5, and since the one-dimensional evaluation method is applied to strong combustion conditions, it is quite credible to select the part of the flow field with relatively uniform air flow (the rear of the combustion chamber) for verification. Using this method, the relative error of the calculated outlet cross-section combustion efficiency value is compared with the known measured value, with a relative error of 0.38%, a relative error of temperature of 0.91%, and a relative error of Mach number of 0.18%.

表1试验测量燃烧室出口截面热动和气动参数数据Table 1 Experimental measurement of thermodynamic and aerodynamic parameter data of the outlet section of the combustion chamber

位置(in，cm)position (in, cm) w(ft/s，m/s)w(ft/s，m/s) T(°R，K)T(°R,K) Tt(°R，K)Tt(°R,K) Mm ηη 35.00(88.90)35.00(88.90) 6476(1974)6476(1974) 3934(2186)3934(2186) 6813(3785)6813(3785) 2.172.17 0.940.94

本发明中所有参数的单位均采用国际单位。The units of all parameters in the present invention adopt international units.

Claims

1. the one-dimensional evaluation method of the burning efficiency of a scramjet engine, it is characterized in that: described evaluation method realizes according to following steps:

Step 1, determine entry of combustion chamber condition and pressure distribution: obtain the ultra-combustion ramjet combustion-chamber wall surface pressure distribution situation by test or numerical simulation, set up the molecular weight and the enthalpy database of each component in the firing chamber according to Physical Property Analysis software ASPEN, set up molecular weight and enthalpy and pressure, temperature and oxygenant and cross the funtcional relationship μ (p of oxygen quotient, T, α) and H (p, T, α); Known combustion chamber inlet total mass flow rate and the shared mark of each composition are determined G _τ, G _o, L _{O τ}, α,

And I _BX, utilizing the mutual conversion between burning efficiency and each constituent mass mark, the fundamental equation group coupling that the simultaneous equation of momentum, energy equation, flow equation and the equation of gas state constitute is found the solution, and above-mentioned four fundamental equations are shown in (1) to (4) formula:

I_{BX} + \underset{F_{σok}}{&Integral;} p_{kc} d \overset{&RightArrow;}{F} - X_{o} = I_{kc} = G_{Σ} w_{kc} + p_{kc} F_{kc} - - - (1)

H_{BX}^{*} - \frac{Q}{G_{Σ}} = g_{τkc} H_{τ} (p_{τkc}, T_{kc}, α = 0) + g_{okc} H_{o} (p_{okc}, T_{kc}, α = \infty) + g_{nckc} H_{nc} (p_{nckc}, T_{kc}, α = 1) + \frac{w_{kc}^{2}}{2} - - - (2)

ρ_{BX} w_{BX} = \frac{{αL}_{oτ}}{1 + {αL}_{oτ}} ρ_{kc} w_{kc} {\overset{&OverBar;}{F}}_{kc} - - - (3)

p_{kc} = ρ_{kc} \frac{R}{μ_{kc}} T_{kc} - - - (4)

Wherein, I is a momentum; X _oBe firing chamber streamwise dissipative force; G _∑Be total working medium mass rate; F is an area,

For relative cross-section amasss,

(p, T are than enthalpy function α) to H, and be special

Be the total specific enthalpy of entry of combustion chamber; Q is the combustion chamber wall surface hot-fluid; G is a massfraction; (p, T α) are the molecular weight function to μ; L _{O τ}Be the chemical equivalent coefficient of oxygenant to fuel; α is that oxygenant is crossed oxygen quotient

G _τAnd G _oBe respectively actual given fuel and oxygenant mass rate; W is a refrigerant flow rate in the firing chamber; R is a universal gas constant; ρ is a working medium density; T represents static temperature;

Wherein, the leftover bits and pieces target is explained: a certain section in " kc " expression firing chamber, " BX " expression entrance section place, " σ ok " expression combustion chamber side wall, " τ " represents fuel bed, " o " expression oxygenant layer, " nc " expression products of combustion layer; The a certain section fuel bed in footnote " τ kc " expression firing chamber, variable " μ _Kc" expression ignition mixture mean molecular weight, F _KcBe a certain section cross-sectional area in firing chamber;

Step 2, provide burning efficiency initial value η ₀:

η = \frac{η_{npak}}{η_{meop}} = \frac{G_{τcz}}{{\overset{&OverBar;}{G}}_{τ}} = \frac{G_{ocz}}{{\overset{&OverBar;}{G}}_{o}} - - - (5)

Step 3, determine each composition quality mark g of section of combustion chamber:

g_{τkc} = \frac{G_{τ} - G_{τcz}}{G_{Σ}} = g_{τ} (1 - η_{0} α^{v}) - - - (6)

g_{okc} = \frac{G_{o} - G_{ocz}}{G_{Σ}} = g_{o} (1 - η_{0} α^{v - 1}) - - - (7)

g_{nckc} = \frac{G_{τcz} + G_{ocz}}{G_{Σ}} = η_{0} (g_{τ} α^{v} + g_{o} α^{v - 1}) - - - (8)

\frac{1}{μ_{kc}} = \frac{g_{τkc}}{μ_{τkc} (p_{τkc}, T_{kc}, α = 0)} + \frac{g_{okc}}{μ_{okc} (p_{okc}, T_{kc}, α = \infty)} + \frac{g_{nckc}}{μ_{nckc} (p_{nckc}, T_{kc}, α = 1)} - - - (9)

Wherein, η _NpakBe real reaction efficient; η _MeopBe theoretical reaction efficiency; η is a burning efficiency; With

When being respectively fuel perfect combustion, fuel that should react and oxygenant mass rate in theory; G _{τ cz}And G _OczBe respectively real reaction intact fuel and oxygenant mass rate; V is a design factor, regulation α≤1, v=1; α 〉=1, v=0;

Step 4, determine the static temperature of a certain section in firing chamber: the static temperature T that determines a certain section in firing chamber in conjunction with the equation of gas state (4) formula and (9) formula _Kc

Step 5, obtain ignition mixture enthalpy and mean molecular weight μ _Kc:

Draw ignition mixture enthalpy and inlet ignition mixture mean molecular weight in conjunction with rerum natura analysis software ASPEN;

Step 6, obtain section of combustion chamber local velocity of sound a and Mach number M:

Obtain section of combustion chamber local velocity of sound and Mach number in conjunction with the equation of momentum (1) formula, flow equation (3) formula;

Step 7, determine combustion chamber wall surface friction factor c _fAnd streamwise dissipative force X _o:

Draw combustion chamber wall surface friction factor and streamwise dissipative force in conjunction with the equation of momentum (1) formula, flow equation (3) formula;

Step 8, obtain ignition mixture flow velocity w:

Step 9, obtain the hot-fluid q of combustion chamber wall surface unit _w:

Step 10, obtain the calculated value of burning efficiency η:

In conjunction with energy equation (2) formula and (6) to (8) formula, obtain burning efficiency calculating formula (24) formula:

η = \frac{H_{BX}^{*} - \frac{Q}{G_{Σ}} - g_{o} H_{o} (p_{okc}, T_{kc}, α = \infty) - g_{τ} H_{τ} (p_{τkc}, T_{kc}, α = 0) - \frac{w_{kc}^{2}}{2}}{(g_{o} α^{v - 1} + g_{τ} α^{v}) H_{nc} (p_{nckc}, T_{kc}, α = 1) - g_{o} α^{v - 1} H_{o} (p_{okc}, T_{kc}, α - \infty) - g_{τ} α^{v} H_{τ} (p_{τkc}, T_{kc}, α = 0)} - - - (24)

Wherein the combustion chamber wall surface hot-fluid calculates and adopts the Reynolds method of approximation:

Q = \underset{F_{σok}}{&Integral;} q_{w} {dF}_{σok} - - - (25)

q_{w} = \frac{c_{f}}{2} ρ_{kc} w_{kc} S (I) (H_{r} - H_{w}) - - - (26)

S (I) = \frac{{2 q}_{w}}{c_{f} ρ_{kc} w_{kc} (H_{r} - H_{w})} - - - (27)

H_{r} = H_{kc} + r \frac{w_{kc}^{2}}{2} - - - (28)

Wherein, S (I) is the reynolds analogue parameter; H _rFor recovering enthalpy; H _wBe wall gas enthalpy; q _wBe combustion chamber wall surface unit's hot-fluid;

Step 11, judge whether burning efficiency is identical with initial value:

Compare η and given initial value η ₀Whether identical, if then execution in step 12; Otherwise get back to step 2, loop iteration is until the calculated value of the burning efficiency η that is met accuracy requirement;

Step 12, end.

2. the one-dimensional evaluation method of the burning efficiency of scramjet engine according to claim 1 is characterized in that: in the step 6, section of combustion chamber local velocity of sound and Mach number calculate the balance dissociating gas method that adopts:

H _kc＝g _τkcH _τ(p _τkc，T _kc，α＝0)+g _okcH _o(p _okc，T _kc，α＝∞)+g _nckcH _nc(p _nckc，T _kc，α＝1)(10)

c_{p} = {(\frac{{&PartialD; H}_{kc}}{{&PartialD; T}_{kc}})}_{p_{kc}} - - - (11)

c_{v} = c_{p} - \frac{{R [1 - {(\frac{{&PartialD; \ln μ}_{kc}}{{&PartialD; \ln T}_{kc}})}_{p_{kc}}]}^{2}}{μ_{kc} [1 + {(\frac{{&PartialD; \ln μ}_{kc}}{{&PartialD; \ln p}_{kc}})}_{T_{kc}}]} - - - (12)

k = \frac{c_{p}}{c_{v}} - - - (13)

a_{kc} = \sqrt{\frac{{kRT}_{kc}}{μ_{kc} [1 + {(\frac{{&PartialD; \ln μ}_{kc}}{{&PartialD; \ln p}_{kc}})}_{T_{kc}}]}} - - - (14)

M _kc＝w _kc/a _kc(15)

Wherein, H _KcBe a certain section burning in firing chamber mixture specific enthalpy; c _pBe specific heat at constant pressure; c _vBe specific heat at constant volume; K is a specific heat ratio; M is a Mach number; A is a local velocity of sound.

3. the one-dimensional evaluation method of the burning efficiency of scramjet engine according to claim 1 is characterized in that: in the step 7, the semiempirical formula of dull and stereotyped no gradient turbulent boundary layer is adopted in the combustion chamber wall surface friction loss:

\frac{0.242 \sqrt{1 - ω - β}}{\sqrt{c_{f}} \sqrt{β}} [\arcsin \frac{\sqrt{β} + \frac{ω}{2 \sqrt{β}}}{\sqrt{1 + \frac{ω^{2}}{4 β}}} - \arcsin \frac{\frac{ω}{2 \sqrt{β}}}{\sqrt{1 + \frac{ω^{2}}{4 β}}}] = 0.41 + \lg (R_{ex} c_{f}) - \lg (\frac{μ_{w}}{μ_{e}}) - - - (16)

β = r \frac{k - 1}{2} M_{kc}^{2} \frac{T_{kc}}{T_{w}} - - - (17)

T_{r} = T_{kc} (1 + r \frac{k - 1}{2} M_{kc}^{2}) - - - (18)

ω = 1 - \frac{T_{r}}{T_{w}} - - - (19)

\frac{μ_{w}}{μ_{e}} = {(\frac{T_{w}}{T_{kc}})}^{n} - - - (20)

X_{mp} = \underset{F_{σok}}{&Integral;} \frac{1}{2} c_{f} ρ_{kc} w_{kc}^{2} d F_{σok} - - - (21)

X _o＝X _n+X _mp (22)

p_{BX} + ρ_{BX} w_{BX}^{2} + \frac{p_{BX} + p_{kc}}{2} ({\overset{&OverBar;}{F}}_{kc} - 1) - X_{o} / F_{BX} = {\overset{&OverBar;}{F}}_{kc} (p_{kc} + ρ_{kc} w_{kc}^{2}) - - - (23)

Wherein, ω and β are the computation process intermediate quantity; T _rBe recovery temperature, r is a coefficient of restitution; T _wBe the chamber wall surface temperature; R _ExBe the Reynolds number under the current coordinate; c _fBe the wall friction coefficient; X _nBe fuel oil support plate aerodynamic drag; X _MpBe combustion chamber wall surface friction force;

Be the ratio of near wall kinetic viscosity with the outer gas stream kinetic viscosity, n is an index, and n is by test determination.