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平面拉瓦尔喷管的环境压力与入口总压的比值从设计工况到第三极限工况(管口处为正激波)逐渐增大时,喷管外的激波现象不同.根据已知的激波反射理论,将设计工况到第三极限工况间的工作状况进一步细分为强斜激波工况、马赫反射工况、双解区和正规反射工况、并将由气流偏转角所表示的发生正规反射和马赫反射的条件用环境压力与总压的比值来表示,找出了强、弱斜激波的环境压力与总压比值的临界值,得到这些临界值随着喷管面积比的变化趋势.最后针对面积比为5的平面拉瓦尔喷管,由理论分析得到其管外发生正规反射、马赫反射、强斜激波反射时对应的压比分别为:0.0841,0.0959和0.2005,并用数值模拟来验证理论分析的正确性.
Plane Laval nozzle ambient pressure and total inlet pressure ratio from the design conditions to the third limit conditions (nozzle at the positive shock) is gradually increased, the shock wave outside the nozzle according to the known Shock wave reflection theory, the working conditions between design conditions and the third extreme working conditions are further subdivided into strong oblique shock conditions, Mach reflection conditions, double solution zones and regular reflection conditions, and the airflow deflection angle The conditions for the occurrence of regular reflections and Mach reflections are expressed as the ratio of ambient pressure to total pressure, and the critical values of ambient pressure and total pressure ratio for strong and weak oblique shocks are found. These critical values are obtained as the nozzle The ratio of the area ratio to the area ratio.Finally, according to the plane Laval nozzle with an area ratio of 5, the pressure ratio corresponding to the normal reflection, Mach reflection and strong oblique shock reflection outside the tube obtained by theoretical analysis is respectively 0.0841, 0.0959 and 0.2005, and numerical simulation to verify the correctness of theoretical analysis.