Design And Numerical Simulation Of Turbo Expander In ORC System

After the optimization of organic medium and aerodynamic thermodynamic calculation to the radial inflow turbine in ORC system, this paper explore an integrated solution to the radial inflow turbine’s design and CFD analysis which based on ANSYS Workbench platform. By establishing a VISTA RTD, BladeGen, TurboGrid, CFX procedure connection, we can easily keep and transfer kinds of parameters and Settings, and improve the speed of research. Specific work for the requirement of enterprise are as follows:By using the REFPROP database to compare and optimize ten kinds of organic medium, with the ORC system for evaporation temperature around 370 K, giving full consideration to its thermodynamic performance, environmental protection and economy, etc, finding that selecting R245 fa as the circulating working medium in this design is reasonable.In radial inflow turbine’s one dimensional design, on the basis of the filtering method, this paper improve the selection of speed ratio and reaction degree method, this method can solve a binary equations to get the speed ratio and reaction, and carries on thermodynamic calculation on the basis of programming, to get the turbine’s efficiency and structure parameters. Then put the turbine’s initial design parameter into the radial inflow turbine preliminary design tool VISTA RTD, to complete the aerodynamic and geometric design. This paper compares the thermodynamic calculation value with VISTA RTD, finding that the deviation is within 10%.Using CFX software to analyze the designed turbine for numerical simulation, and analyze in detail including 0.3 mm tip clearance of blade tip leakage loss and the influence of different tip clearance on the impeller performance. By CFD calculation, the radial inflow turbine’s wheel efficiency basicly meet the requirement of the subject, but the efficiency is still low, the secondary flow loss is bigger, remains to be further optimized.With various factors integrated in this paper, getting a radial inflow turbine design scheme, the wheel efficiency is 78.7%, and meets the requirement of the subject.