轴流涡轮基元级动叶稠度特性的数值研究

利用商用软件数值模拟了5个不同动叶稠度的轴流涡轮基元级的非定常流动情况,以研究动叶稠度对轴流涡轮基元级性能和流动情况的影响.通过对动叶稠度对基元级反力度、叶片进出口气流角、转子和静子中的流场及损失影响情况的考察研究,发现动叶稠度的改变对涡轮基元性能和流动情况的影响与静叶稠度存在重要关系.静叶稠度不变时,动叶稠度的改变通过影响流过涡轮基元级的流量来使基元级的反力度发生变化.当动叶稠度过大时,气流在转子中会过度膨胀加速而产生激波损失及其与附面层干涉形成的流动分离损失.动叶稠度过小时,转子进口会出现极大的正攻角致使动叶吸力面发生大范围的流动分离.静叶稠度一定时,存在一个最佳的动叶稠度,使涡轮基元级呈现最好的性能.

Numerical study on the rotor solidity characteristics of axial turbine element stages

To explore the influence of the rotor solidity on the axial turbine element stage flow status and performance,unsteady numerical simulations on the turbine element stages with five different rotor solidity were conducted,and the rotor solidity influence on the element stage reaction,blade inlet and outlet flow angles,stator and rotor flow fields and loss status was investigated.The research results indicate that the effects of the rotor solidity alteration on the turbine element stage flow status and performance are directly associated with the stator solidity.When the stator solidity remains constant,The rotor solidity alteration changes the turbine element stage reaction by changing the mass flow rate through the element stage.As the rotor solidity increased to a certain extent,shocks will arise from the excessive expansion and acceleration of the gas flow in the stator region,as well as the flow separation caused by the shock interaction with the boundary layer.As the rotor solidity reduced to a certain extent,an large positive flow incidence will occur at the rotor inlet and cause a great range of flow separation on the rotor suction side.When the stator solidity remains constant,there’s one best rotor solidity,resulting in the best turbine element stage performance.