基于有机工质真实气体模型的超音速喷嘴设计

The Design of Supersonic Nozzle for Organic Fluid Based on Real Gas Model

为了研究临界或超临界状态有机工质的气动特性,采用计算超音速流动的特征线法,设计了基于真实气体模型的超音速喷嘴。研究了甲苯的5个真实气体膨胀过程,初始状态总温均为600 K,压力分别4 MPa,3.5 MPa,2 MPa,1MPa,0.1 MPa,其中4 MPa,3.5 MPa接近于有机物朗肯循环(ORC)涡轮静叶内膨胀初始状态,甲苯处于稠密气体状态;比较发现,当甲苯处于临界或超临界状态时,喷嘴设计结果明显不同于理想气体状态。以本方法为基础设计了高膨胀比向心涡轮静叶,模拟结果展示了基于真实气体模型的超音速喷嘴设计的可行性。

In order to investigate the features of gas dynamic nozzles operating with supercritical or close to critical Organic Fluid,The supersonic nozzle based on real gas model is designed by the Method of Characteristics（MOC）,which is always applied to calculate supersonic flow field.Toluene is often used as working fluid in organic Rankin cycle（ORC）.Five exemplary real-gas expansions,originating from a reservoir at a temperature of 600 K and at a pressure of 4,3.5,2 MPa and 1 MPa,respectively,were considered and compared to the corresponding dilute gas case,for which reservoir conditions are 600 K and 0.1 MPa.When flow states close to supercritical or critical point,the nozzle shape is different from the well-known ideal-gas results.Development of a supersonic nozzle design method based on real gas model can lay a foundation for the optimization of supersonic ORC turbine stators.