1MW有机工质离心透平设计与性能研究

The Design and Aerodynamic Analysis on 1MW Centrifugal Turbine of Organic Working Fluid

针对MW级有机朗肯循环系统,设计了单级跨音速和四级亚音速两组离心透平,两组透平均为等叶高直叶片,结构尺寸相当。利用数值模拟方法研究了气动性能,结果表明:设计工况下,两组离心透平在设计工况下流道内流线顺畅,压力分布合理。单级跨音速离心透平等熵效率为83.44%,四级亚音速离心透平等熵效率为86.7%。在变工况条件下,结合有机工质的物性,引入工质比热比C_(p)/C_(v)修正级的流量计算公式,得到了有机工质离心式透平焓降和流量随着热力参数的变化规律。四级亚音速离心透平的整体性能优于单级跨音速离心透平。

Inthisstudy,a single-stage transonic centrifugal turbine and a four-stage centrifugal turbine was designed for an ORC system with capacity of one megawatt.The structure dimensions of two turbines weresimilar.The aerodynamic performance of the designed turbines was investigated by CFD technology.Numerical simulation results suggested that the fluid moves smoothly and the pressure distribution was maintained within a reasonable range.Under the design condition,the isentropic efficiency of the single-stage transonic centrifugal turbine was 83.44%,and the stage group efficiency of the four-stage centrifugal turbine was 86.7%.Under the off-design conditions,the ratio of specific heats C_(p)/C_(v)of working medium with considering physical properties of organic fluids was introduced to correct the calculation formula of enthalpy and the mass flow rate.The overall performance of the four-stage centrifugal turbine was better than the single-stage transonic centrifugal turbine.