涡轮级内湍流度影响的非定常数值模拟

Numerical simulation on unsteady flow with turbulence intensity effects in a turbine stage

关键词:  涡轮叶栅  非定常流  热斑  湍流度  数值仿真

Key words:  Turbine cascade  Unsteady flow  Hot streak  Turbulence  Numerical simulation

摘要:

通过求解二维雷诺平均Navier Stokes方程 ,数值模拟了不同进口湍流度下的涡轮级中的非定常流场及温度场。结果表明 ,增大湍流度对叶栅通道内时均压力分布影响很小 ,但是对涡轮级中的温度分布会产生很大影响。当涡轮进口有热斑存在时 ,增大湍流度将会使热斑中的热流体温度扩散更快 ,从而叶栅通道中的温度场分布趋向均匀 ,同时动叶压力面侧与吸力面侧的时均温度差别减小 ,沿动叶弦长方向上的温度分布也更平缓

Abstract:

A two dimensional Navier Stokes equation was solved to predict unsteady flow and temperature fields with different turbulence intensity in a turbine stage. It was found that turbulence intensity had significant effects on the temperature distribution but the pressure distribution was not so. When hot streak was introduced in the turbine’s inlet, high turbulence intensity would make the temperature of hot gas dissipate more quickly, and the temperature distribution tend to be more uniform. The temperature discrepancy between suction surface and pressure surface of rotor would be decreased, and the temperature profile along the chord become more even.