为了探究跨声速飞行工况下混合并联涡轮基组合循环(Turbo based combine cycle,TBCC)动力的冲压流道在冷通气状态下的流动及阻力特性,构建了一个巡航马赫数为4.0、基于混合并联TBCC动力的高马赫数飞机模型,通过三维定常数值模拟方法研...为了探究跨声速飞行工况下混合并联涡轮基组合循环(Turbo based combine cycle,TBCC)动力的冲压流道在冷通气状态下的流动及阻力特性,构建了一个巡航马赫数为4.0、基于混合并联TBCC动力的高马赫数飞机模型,通过三维定常数值模拟方法研究了其在Ma_(∞)=0.7~1.6,H_(∞)=11 km飞行环境下飞机-发动机内/外流动及其耦合特征。计算结果表明:跨声速状态下,冲压进气道入口处气流增压后的静压达到了自由来流滞止压力的85%~90%,气流接近于滞止状态,说明组合进气道存在强烈的节流效应,且冲压通道的喉道是组合进气道节流效应的主要贡献者;冲压发动机尾喷管的排气流动同时受到飞机绕流及涡轮通道排气系统等多方面的干扰,且涡轮通道排气射流对冲压发动机尾喷管气流本身就存在膨胀压缩及排气引射等多种干扰机制。阻力分析表明,压差阻力系数高出内表面摩擦阻力系数2个数量级,是跨声速状态下冲压流道阻力的主要来源;亚声速状态下,进气道阻力占比达到了60%~80%,是冲压流道的主要阻力部件,而Ma_(∞)>1.0超声速状态下,进气道阻力占比随飞行马赫数的增大而逐步减小,尾喷管的阻力则快速增长,阻力贡献逐渐向尾喷管转移,两者趋于接近。展开更多
A three-part numerical investigation has been conducted in order to identify the flow separation behavior––the progression of the shock structure, the flow separation pattern with an increase in the nozzle pressure ...A three-part numerical investigation has been conducted in order to identify the flow separation behavior––the progression of the shock structure, the flow separation pattern with an increase in the nozzle pressure ratio（NPR）, the prediction of the separation data on the nozzle wall,and the influence of the gas density effect on the flow separation behavior are included.The computational results reveal that the annular conical aerospike nozzle is dominated by shock/shock and shock/boundary layer interactions at all calculated NPRs, and the shock physics and associated flow separation behavior are quite complex.An abnormal flow separation behavior as well as a transition process from no flow separation at highly over-expanded conditions to a restricted shock separation and finally to a free shock separation even at the deign condition can be observed.The complex shock physics has further influence on the separation data on both the spike and cowl walls, and separation criteria suggested by literatures developed from separation data in conical or bell-type rocket nozzles fail at the prediction of flow separation behavior in the present asymmetric supersonic nozzle.Correlation of flow separation with the gas density is distinct for highly overexpanded conditions.Decreasing the gas density or reducing mass flow results in a smaller adverse pressure gradient across the separation shock or a weaker shock system, and this is strongly coupled with the flow separation behavior.The computational results agree well with the experimental data in both shock physics and static wall pressure distribution at the specific NPRs, indicating that the computational methodology here is advisable to accurately predict the flow physics.展开更多
文摘为了探究跨声速飞行工况下混合并联涡轮基组合循环(Turbo based combine cycle,TBCC)动力的冲压流道在冷通气状态下的流动及阻力特性,构建了一个巡航马赫数为4.0、基于混合并联TBCC动力的高马赫数飞机模型,通过三维定常数值模拟方法研究了其在Ma_(∞)=0.7~1.6,H_(∞)=11 km飞行环境下飞机-发动机内/外流动及其耦合特征。计算结果表明:跨声速状态下,冲压进气道入口处气流增压后的静压达到了自由来流滞止压力的85%~90%,气流接近于滞止状态,说明组合进气道存在强烈的节流效应,且冲压通道的喉道是组合进气道节流效应的主要贡献者;冲压发动机尾喷管的排气流动同时受到飞机绕流及涡轮通道排气系统等多方面的干扰,且涡轮通道排气射流对冲压发动机尾喷管气流本身就存在膨胀压缩及排气引射等多种干扰机制。阻力分析表明,压差阻力系数高出内表面摩擦阻力系数2个数量级,是跨声速状态下冲压流道阻力的主要来源;亚声速状态下,进气道阻力占比达到了60%~80%,是冲压流道的主要阻力部件,而Ma_(∞)>1.0超声速状态下,进气道阻力占比随飞行马赫数的增大而逐步减小,尾喷管的阻力则快速增长,阻力贡献逐渐向尾喷管转移,两者趋于接近。
文摘A three-part numerical investigation has been conducted in order to identify the flow separation behavior––the progression of the shock structure, the flow separation pattern with an increase in the nozzle pressure ratio（NPR）, the prediction of the separation data on the nozzle wall,and the influence of the gas density effect on the flow separation behavior are included.The computational results reveal that the annular conical aerospike nozzle is dominated by shock/shock and shock/boundary layer interactions at all calculated NPRs, and the shock physics and associated flow separation behavior are quite complex.An abnormal flow separation behavior as well as a transition process from no flow separation at highly over-expanded conditions to a restricted shock separation and finally to a free shock separation even at the deign condition can be observed.The complex shock physics has further influence on the separation data on both the spike and cowl walls, and separation criteria suggested by literatures developed from separation data in conical or bell-type rocket nozzles fail at the prediction of flow separation behavior in the present asymmetric supersonic nozzle.Correlation of flow separation with the gas density is distinct for highly overexpanded conditions.Decreasing the gas density or reducing mass flow results in a smaller adverse pressure gradient across the separation shock or a weaker shock system, and this is strongly coupled with the flow separation behavior.The computational results agree well with the experimental data in both shock physics and static wall pressure distribution at the specific NPRs, indicating that the computational methodology here is advisable to accurately predict the flow physics.
