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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。
It is a new idea to construct hypersonic wind tunnel for a long time to obtain long-time high-pressure and high-enthalpy experimental airflow in the colliding piston compression wind tunnel. The simplified analysis and numerical calculation are used to analyze the working principle of the crash piston compression wind tunnel to verify the feasibility of the crash piston compression wind tunnel. The simplified analysis considers the constant pressure specific heat as a function of temperature. Based on the hypothesis of flow field uniformity, the experimental time and the evolution of experimental gas state parameters over time are given. The commercial software Fluent is used to simulate the flow field of a full-scale wind tunnel. The simulation results show that the squeeze type constant pressure device can keep the pressure in the wind tunnel approximately unchanged for a long time (about 25ms) However, the compression of the impact piston causes uneven temperature distribution in the flow field inside the pipe, causing the temperature to fluctuate (no more than 180K), which is a problem that needs to be solved for the compression piston of the piston.