Aerodynamic Analysis And Optimization Of Radial Turbine Intake Components

Compressed air energy storage technology can solve the problem of intermittent which the renewable energy has, dispatch load and reduce the generating capacity. It can save energy and has a great potential for application. Research on compressed air energy storage system has great significance for solving the energy and environmental issues that the current social faces.Expander is one of the most important parts of the compressed air energy storage system. In the MW-class compressed air energy storage system, multi-stage radial turbine is used as expander. The radial inflow turbine is consist of intake components, guide vane, wheel and exhaust structure. The intake components’efficiency has an important influence on the efficiency of the radial turbine. In this dissertation, we mainly focus on the research of the two kinds of intake component, chamber and volute. On the basis of analysing flow field in the chamber, some rectangular cross-section scrolls are designed, then a comparative analysis of the effect of intake components on the radial turbine’s efficiency. The main contents of this thesis are as follows:1. A design of the rectangular cross-section volute using two-dimensional design method for radial turbine is carried out. Then a numerical simulation of the radial turbine with the chamber and the volute is carried out separately to study the effect of intake components on radial turbine’s performance and losses. The results of the numerical simulation shows the loss within the chamber is larger than that in volute. The second flow is observed in the guide vane passage of the radial turbine with chamber. Compared with chamber, the volute can increase the efficiency, mass flow and power of the radial inflow turbine.2. To study the effect of the non-dimensional volute aerodynamic size S1and the width of the volute’s cross-section B on radial turbine’s performance, design some rectangular cross-section volutes for the radial inflow turbine. The radial turbine with a volute whose S1is approximately equal to0.2has the maximum efficiency. The width of the volute’s cross-section have no effect on radial turbine’s performance.3. Study on the effect of the symmetry of volute on the radial inflow turbine’s performance is carried out. Flow structure and secondary flow distribution within the volute is analysed. The vortex structure is observe nearby the leading edge within the symmetric and asymmetric volute’s outlet channel. Within the symmetric volute’s outlet channel, there are two vortex structures which is symmetrical along the axial direction. While in the asymmetric volute’s outlet channel, the intensity of the vortex near the hub is high, and the intensity of the vortex near the shroud is low. The radial inflow turbine with the asymmetric volute have a little lower efficiency.