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针对某微型涡轮发动机(MTE)原理样机的直径为78.4mm的微型轴流涡轮,采用数值模拟手段研究了叶尖间隙泄漏对该厘米级高亚声微型轴流涡轮流场结构及涡轮性能的影响.结果表明:微型轴流涡轮相对叶尖间隙尺寸在3.1%~4.6%,明显高于常规轴流涡轮;微型轴流涡轮叶尖间隙泄漏涡影响范围较常规轴流涡轮扩大(至叶中高度),泄漏损失占涡轮级总损失的35%,也较常规轴流涡轮明显增大.研究获得了间隙尺寸对该厘米级高亚声微型轴流涡轮性能的影响规律,叶尖相对间隙尺寸每增加1%叶高,效率最快下降1.9%,其变化幅度较常规轴流涡轮更为明显.最后,根据工程安装的限制(离心力变形及热变形、轴承游隙、加工装配误差等),确定了一个较优的叶尖间隙(0.4mm),通过数值模拟获得了在该间隙下的涡轮性能参数:落压比为2.12,效率为0.87,流量为0.35kg/s.
Aiming at the miniature axial turbine with a diameter of 78.4mm of a prototype micro turbine engine (MTE), the effect of tip clearance leakage on the flow field structure and turbine performance of the centimeter-class high subsonic micro-axial turbine was investigated by numerical simulation. Results The results show that the relative tip clearance of the miniature axial turbine is between 3.1% and 4.6%, which is obviously higher than that of the conventional axial flow turbine. The influence range of tip leakage of micro axial flow turbine blades is larger than that of conventional axial turbines The leakage loss accounted for 35% of the total turbine loss, compared with the conventional axial turbine was significantly increased.This study obtained the influence of the gap size on the performance of the centimeter-class high subsonic micro-axial turbines with each additional 1% High, and the efficiency dropped by 1.9% at the earliest, which is more obvious than that of conventional axial turbines.Finally, according to the limitations of installation (centrifugal deformation, thermal deformation, bearing clearance, machining assembly error, etc.), a better The tip clearance (0.4mm) was obtained by numerical simulation. The turbine performance parameters under this clearance were obtained. The pressure ratio was 2.12, the efficiency was 0.87 and the flow rate was 0.35kg / s.