Design And Performance Analysis Of Axial Turbine With Real Working Fluid

Axial turbine plays an important role in the development of national economy.In recent years,efficient and clean energy has become an urgent need for sustainable development.With the development of Organic Rankine Cycle(ORC),Brayton Cycle of supercritical carbon dioxide turbine and supercritical water gasification of coal hydrogen production technology,the design of axial turbine with real working fluid has become a hot research topic.The main work of this paper is to study the design and performance analysis method of axial turbine with real working fluid.Firstly,this paper developed a one-dimensional design program of axial turbine based on Fortran language.This program integrates the Craig&Cox loss model and the Ainley deviation angle model to improve the performance prediction precision of axial turbine.It also integrates the bilinear interpolation fluid property calculation module to realize the one-dimensional design of axial turbine with real working fluid.In order to make the turbine design more efficient,this paper combines the one-dimensional design method with the optimization algorithm,and proposes an optimization design method of axial turbine with real working fluid.Subsequently,the feasibility and accuracy of the one-dimensional design method were verified by the four-stage axial turbine from Hanover University,in which the maximum error of blade height is-5.5871%.Secondly,combined with the simple radial equilibrium equation to consider the radial variation of aerodynamic parameters,the quasi-one dimensional performance analysis method of the axial turbine is summarized based on the mean-line performance analysis method.The calculation of the axial flow turbine choking condition was also studied.The maximum mass flow of the blade exit is used as a calculation method for choking condition.In addition,the same loss model and the fluid property calculation module as the design method are integrated in the program to realize the performance prediction of axial turbine with real working fluid.Subsequently,the accuracy and feasibility of the program were verified with turbine test data from NASA.The maximum error of the choking mass flow is 0.64% and the maximum error of isentropic efficiency is 1.129%.Finally,based on the developed one-dimensional design and performance analysis program of the axial turbine,the design and performance analysis of axial turbine were carried out for supercritical carbon dioxide and steam mixed fluids.Subsequently,the design turbine was verified by three-dimensional numerical simulation.The result shows that isentropic efficiency of the design point is 5.21% greater than the CFD result,which is mainly due to the large secondary flow loss caused by the secondary flow in the small aspect ratio blade and the tip clearance leakage in the rotor blade.The result of performance analysis shows that the trend of the choking mass flow predicted by the program is consistent with the CFD result and the maximum error is 0.842%.The efficiency performance map of the CFD result was slightly different,and the design point isentropic efficiency is 1.5% higher than the CFD result,and the maximum error of isentropic efficiency in off design points is 4.125%.