轴流式涡轮机动叶片的叶顶间隙对其气动性能影响

Influence of Tip Clearance Variation on Aerodynamic Performance of Axial Turbine

采用数值方法对不同叶顶间隙下某型号船用轴流式涡轮机的气动性能进行了对比分析.结果表明,叶顶间隙对喷嘴环前缘的压力分布和涡轮内的温度分布影响明显,过小和过大的叶顶间隙都会导致喷嘴环前缘高压力区的产生,并导致涡轮内局部高温度区域扩大;随着叶顶间隙的增大,喷嘴环后缘底部、吸力面及叶顶间隙内局部高熵区随之增大,燃气能量损失增大.

Numerical methods were used to analyze influence of different tip clearances on aerodynamic performance of a marine axial turbine. The results show that the tip clearance has obvious effect on pressure distribution of the nozzle ring leading edge and temperature distribution of the turbine. Too small and too large tip clearance lead to high pressure area produced in the leading edge of the nozzle ring and local high temperature area expanded in the turbine. It also indicates that the increase of tip clearance causes high entropy area produced and expanded at the bottom of the trailing edge and the suction side of the nozzle ring and in the tip clearance. As a result,energy loss in the turbine is enlarged.