RBCC模态特征与热力循环分析样本全覆盖策略

Characteristics of RBCC operation mode and strategy for full-sample analysis to thermodynamic cycle

关键词:  RBCC  低速段  模态  样本全覆盖  热力循环

Key words:  RBCC  Low-speed range  Operation mode  Full-sample analysis  Thermodynamic cycle

摘要:

为了获得样本全覆盖的RBCC全模态热力循环分析策略，针对目前尚有争议的低速阶段，采用数值模拟方法研究了支板式RBCC构型在Ma=0~2的流场演化特性，基于对流场演化的认识，区分了火箭-冲压联合工作阶段的模态，提出了除纯火箭模态以外的RBCC样本全覆盖的热力循环分析方法策略。研究结果表明，火箭-冲压联合工作阶段时，RBCC的工作模态包括引射模态、“火箭冲压协同”模态和“加力冲压”模态；在亚声速范围，只要正确赋值来流总温、总压，零速引射分析方法可以用于确定有速度条件的进气道入流流量和混合室出口条件；存在“扫掠激波”的超声速阶段与高亚声速阶段的流场特征相似，零速引射分析方法可用于存在“扫掠激波”的超声速阶段，输入条件取“扫掠激波”后的滞止参数；将零速引射分析方法和以燃烧区特征马赫数为表征的等效热力过程分析方法结合，可以实现RBCC除纯火箭模态以外的各模态样本全覆盖的热力循环分析。

Abstract:

In order to obtain the strategy for achieving full-sample analysis to RBCC thermodynamic cycle， numerical simulation was performed to investigate the flow structure evolution of a strut-based RBCC contraposing the low-speed range（Ma=0~2）which is still controversial. Based on the knowledge of flow evolution， the operation modes of RBCC were distinguished at the stage when the rocket and ramjet work synergistically， and the strategy for full-sample analysis to RBCC thermodynamic cycle was proposed （the rocket mode excluded）. The results show that when the rocket and ramjet work synergistically， the operation modes contain ejector mode， rocket-ramjet synergy mode and augmentation ramjet mode. At subsonic speed， taking the total pressure and total temperature of the inflow as the input parameters， the analysis model for zero-speed ejection process can be applied to determine the mass flow rate of inlet and flow parameters of mixer outlet. At supersonic speed when “sweep shock” exists， the flow characteristics are similar to that at high subsonic speed. Therefore， the analysis model for zero-speed ejection process can be also applied at this stage， and the stagnation conditions after the “sweep shock” are taken as the input parameters. Combined the analysis model for zero-speed ejection process with the analysis method for equivalent thermo-process which is devised with characteristic Mach number in combustion zone， all of the entry conditions and thermo-processes can be included. This means full-sample analysis to thermodynamic cycle is realized except for the rocket mode.