小型海洋温差能向心透平的性能研究

PERFORMANCE RESEARCH OF RADIAL-INFLOW TURBINE IN OCEAN THERMAL ENERGY CONVERSION

针对海洋温差能发电系统设计了发电功率为3 kW的向心透平,并使用CFD技术对设计的透平进行仿真研究和变工况分析,最后分析了动静叶径向间隙以及转子叶片数量对向心透平性能的影响。结果表明:设计的透平性能良好,等熵效率为84.96%;随着转速升高,透平的效率先增大后减少;透平的最佳转速也会随入口压力的增大而增加。入口压力升高会增加透平的输出功;随着转速的增大,流量逐渐减小。合理选择喷嘴与动叶轮之间的径向间隙,可使喷嘴出口处工质流动更加均匀;另外,将透平的转子叶片数量增加到8个,可提高透平性能。

Aiming at the high-efficiency OTEC application,a 3 kW radial-inflow turbine using R134a was constructed.In addition,a 3D CFD simulation was carried out to research the turbine performance and analyze the variable conditions.Finally,the influences of radial clearance and the number of rotor blades on the performance of radial-inflow turbines are analyzed.It is indicated that the performance of the designed turbine is satisfactory with a theoretical isentropic efficiency of 84.96%.The results show that the optimal rotational speed of turbine increases with the increasement of inlet pressure.When the rotational speeds deviate from the optimal value,the turbine efficiency decreases.The results also indicate that the increasement of inlet pressure increases the output work of turbine.With the increasement of rotational speed,the flow rate gradually decreases.In terms of optimization,the radial clearance between the nozzle and the rotor makes the working fluid flow more uniform at the nozzle outlet.Finally,the turbine performance is improved by increasing the number of rotor blades to 8.