航空发动机涡轮轮缘封严数值模拟

Numerical simulation on aero-engine turbine rim sealing

航空发动机涡轮轮缘的封严对于保护轮盘腔室至关重要。为防止主流高温燃气进入轮盘腔室,需通入低温冷气对涡轮轮缘进行封严。采用二维RANS模型和SST湍流模型研究不同封严流量对封严效率的影响,并用压力参数法确定最小封严流量,研究不同封严层高度对封严效率的影响。结果表明:随着封严流量的增加,涡轮轮缘逐渐达到完全密封,涡轮轮缘封严效率增加;同时,腔内封严气体外流至主流,导致腔外主流压力增加,使封严气体对主流气体产生一定影响;封严气体充满轮盘腔,使高温主流气体很难进入轮盘腔,同时主流气体与封严气体在外层封严入口区域发生热交换,入口处主流气体温度显著降低,提高了封严效率;实验结果同时表明,不同封严层高度对封严效率基本没有影响。

Aero-engine turbine rim sealing is vital for rotor-stator system protection.In order to avoid main flow high temperature gas ingesting into rotor-stator system,it is necessary to induce low temperature gas inflow to rotor-stator system.2D RANS model and SST turbulence model are used to study the effect of different sealing flow on sealing efficiency,the minimum sealing flow is determined by pressure parameter method,the influence of different seal heights on sealing efficiency is studied.Results show that with the increase of sealing flow,the turbine flange is gradually sealed and the sealing efficiency of turbine rim increases.At the same time,the outflow of sealing gas from turbine cavity into mainstream results in the increase of mainstream pressure,which makes the sealing gas has a certain influence on the main stream.Because the sealing gas is filled with disk cavity,it is difficult for the high-temperature mainstream gas to enter the disk cavity,and the heat exchange between mainstream gas and sealing gas occurs in the entrance area of layer seal,which makes great change of mainstream gas temperature,and improves the sealing efficiency;meanwhile,experimental results show that different sealing layer heights has few effect on sealing efficiency.