壁面压力可控的基准流场设计参数影响研究与优化设计

Effects of Design Parameters Analysis and Optimization Design of Basic Flowfield with Controlled Pressure Distribution

关键词:  高超声速  基准流场  壁面压力规律  响应面模型  优化设计

Key words:  Hypersonic  Basic flowfield  Wall pressure rise law  Response surface model  Optimization design

摘要:

根据有旋特征线理论，设计了沿程壁面压力分布可控的轴对称基准流场，分析了Ma=6.5状态基准流场的设计参数(包括壁面前缘压缩角、中心体半径和壁面压升规律等)的影响规律。结果表明:前缘压缩角的增大会使基准流场的增压比增加、总压恢复降低；较小的中心体半径有利于减小内收缩比，提高流场起动性能；壁面压力梯度递增的基准流场的压缩效率高。最后，针对基准流场，建立了多项式响应面模型并利用多目标遗传算法进行优化，根据优化获得的Pareto最优前沿选取两个流场进行比较。和选定的流场长度、出口总压恢复系数基本不变的其中一流场相比较，另一流场的收缩比增加了9.5%，增压比提高了14%，喉道马赫数降低了约3.2%，说明优化结果可为选取性能优良的基准流场提供参考。

Abstract:

Axisymmetric basic flowfield with controlled wall pressure gradient is designed using the rotational method of characteristics. The effects of basic flowfield design parameters such as leading edge deflection angle，center body radius and wall pressure law are studied at Ma=6.5. The results show that the pressure compression ratio would increase and total pressure recovery would decrease with the leading edge deflection angle increase. Small center body radius could reduce the internal compression ratio and improve the starting performance of basic flowfield. Moreover，the basic flowfield with wall pressure gradient increasing has the high compression efficiency. At last，the overall performances of the optimized basic flowfield is studied by the multi-objective GA( genetic algorithm) based on the polynomial response surface at design point and the performances of two different basic flowfields which are choosed due to Pareto optimal front are compared. The results indicate that compared with one basic flowfield that the length and the total pressure recovery of outlet almost remain unchanged，the contraction ratio of the other basic flowfield raises 9.5%，the pressure compression ratio raises 14%，the Mach number of throat decreases 3.2%，which verifies that good performance flowfield could be designed on the basis of the optimization results.