长实验时间对撞活塞压缩风洞原理研究

对撞活塞压缩风洞可获得长时间的高压高焓实验气流,是建造长时间运行高超声速风洞的新思路。采用简化分析和数值计算分析对撞活塞压缩风洞的工作原理,以验证对撞活塞压缩风洞的可行性。简化分析考虑定压比热随温度变化,基于流场均匀性假设,给出了实验时间以及实验气体状态参数随时间变化历程。采用商业软件 Fluent 对全尺寸风洞流场运行过程进行数值模拟,模拟结果表明:挤压式恒压装置可使风洞在较长时间内(约25ms)保持压强近似不变,与简化分析结果相符,但对撞活塞压缩会使管道内流场温度分布不均匀,导致温度出现波动(相差不超过180K),这是对撞活塞压缩风洞一个需要解决的问题。

Studies on principles of long-running shot tunnel driven by opposite compression piston drivers

The theoretical basis of the long-running shot tunnel driven by opposite compres-sion pistons is laid.The long-running shot tunnel driven by opposite compression pistons can provide long-lasting high enthalpy and high pressure experimental gas flow,which is a new idea to build long-running hypersonic tunnels.The operation principles of the long-running shot tun-nel driven by opposite compression pistons are analyzed by theoretical simplification and computa-tional fluid dynamics to validate its feasibility.In theoretical analysis,based on the uniform flow field assumption,the test time and the time histories of pressure and temperature are presented with the consideration of the specific heat at constant pressure changing with temperature.The operation of the tunnel is simulated numerically by commercial code Fluent.The results indicate that the pressure of the experimental gas can be kept nearly constant with pressure stabilizer by extruding for about 25 microseconds,that is consistent with theoretical analysis results.Because of the compression of the opposite pistons,the temperature of the flow field is non-uniform and the temperature fluctuation amplitude is less than 180K.This is a notable problem of long-run-ning shot tunnel driven by opposite compression pistons that needs to be resolved.