壁面粗糙度对超临界二氧化碳透平性能影响数值研究

Numerical investigation on the wall roughness of a supercritical carbon dioxide axial turbine

针对某型超临界二氧化碳(S-CO_(2))轴流透平,结合不同工况试验测试结果进行了带粗糙度的仿真与测试的对比分析,重点讨论了壁面粗糙度对机组性能的影响。研究结果表明:采用的壁面粗糙度数值计算方法能够较为准确地评估透平不同负荷工况性能;与测试结果相比,效率误差最大为1.82百分点;壁面粗糙度使得透平整体性能下降,对于本透平开机升功率过程中5个工况,在Ra1.6粗糙度等级下效率最大下降2.8百分点,且涡轮级粗糙度对透平性能影响更加明显;壁面粗糙程度越严重,涡轮级效率下降越大;在非设计工况,粗糙度达到Ra6.3等级时效率最大下降11.6百分点,壁面粗糙度加剧了动叶压力面的流动分离,造成了较大的摩擦损失,严重影响透平性能。研究成果为后续S-CO_(2)透平设计与性能研究提供了技术支撑和依据。

A comparative analysis between simulation and test with roughness is carried out for a supercritical carbon dioxide(S-CO_(2))axial turbine with different operating conditions,focusing on the roughness impact of the turbine performance.The results show that the numerical calculation method of wall roughness is able to assess the performance of the turbine at different load conditions accurately.Compared with test result,the maximum efficiency error is 1.82 percentage point.Wall roughness degrades the overall performance of the turbine,with a maximum efficiency drop of 2.8 percentage point at Ra1.6 roughness level during the five working condition,and the turbine stage roughness has a more obvious effect on the turbine performance.In addition,the more severe of wall roughness,the greater reduction of turbine efficiency.In non-design operating conditions,the efficiency drops by 11.6 percentage point at Ra6.3 roughness level.The wall roughness exacerbates flow separation of pressure surface,causing greater friction losses and serious affecting of turbine performance.The research can provide technical support for the design and performance simulation of S-CO_(2)axial turbines.