Aerodynamic Optimization Study Of High-Speed ORC Radial-inflow Tubine

The Organic Rankine Cycle power generation technology receives more and more attentions according to the widely utilization of waste heat recovery and renewable energy. As the core component of the ORC system the expander is influential in determing the cycle performance, so lots of researchers throw their attention on it. The radial inflow turbine is popular among the small scale ORC system. There are mature commercial ORC radial inflow turbines in developed countries, but it’s not available in China. The thesis aims at aerodynamic optimization study of radial inflow turbine, the main content is as follows:Using MATLAB software calling NIST-Refprop refrigerant library to encode the meanline design process of the ORC radial inflow turbine. Selecting the six input parameters to do the parametric study to investigate the sensitivity of the efficiency and size to the variation of the input parameters. Otherwise, introducing the genetic algorithm to do the optimization of the mean-line design. And the optimal mean-line design with efficiency of 85.67% is achieved. And the rotational speed is 57920 rmp.On the basis of the mean-line design, using the Vista RTD and BladeGen softwares to construct the 3D geometry of the rotor and stator, and the TurboGrid software is applied to generate computational mesh. CFD simulations are performed with ANSYS-CFX. The result shows that the 3D CFD results are in relatively good agreement with the 1D mean-line design. Moreover, a CFD simulation is taken to investigate the influences of various blade numbers and stator blade inlet angles.In order to improve the performance and the distribution of streamline, the response surface method is adopted to research the blade profile of the stator. The BladeGen software is employed to construct the NACA profile of stator blade on the basis of Bezier curve, and four control parameters are considered as the variables to design the blade. Box-Behnken experiment design method is adopted to do the experiment design, 29 cases of differenent blade profile are completed with CFX software to get the nozzle efficiency. The response surface method is used to investigate the influence of the control parameters on the nozzle efficiency to decide the optimal profile design of best efficiency. Compared to the original design, the nozzle efficiency increases 2%, and the distribution of streamline is improved.