微燃机气封装置的数值模拟

为了将旋转部件与静止部件之间不同压力的空间隔开,微燃机中采用了气封装置以减少泄流量。泄漏流量的大小,以及其对主流的干扰,微燃机设计时必须加以认真考虑。工作时通过间隙而泄漏的流量过大,必然会对其整体效率产生重大影响。通常,在间隙处采用特殊结构来控制泄流量的大小,减少间隙对微燃机总体效率的影响。本文采用三维数值模拟对微燃机压气机与透平之间的间隙流动进行模拟分析,通过不同工况的比较以及对其内部流场进行分析,研究了气封内部流动特性,使得微燃机总体计算可考虑间隙引起的泄流对微燃机总体效率的影响。

NUMERICAL SIMULATION ON THE LABYRINTH SEAL OF A MICRO GAS TURBINE

In order to divide the space between rotating parts and quiescent parts in micro gas turbine, the labyrinth seals are used to decrease the leakage loss. Because the leakage may affect the total efficiency of micro gas turbine, it is necessary to consider carefully the leakage in designing micro gas turbine and to decrease the disturbance to the main flow. Usually, the special structure is used to control the leakage between tip clearances. In the paper, a 3-D numerical simulation solver is used to investigate and calculate the flow field in clearance between the compressor and the turbine. By comparing the different flow conditions, flow characteristics in labyrinth seal are studied. It is possible to take into account the leakage flux in clearance and the effect to total efficiency of the micro gas turbine.