部分进气超临界二氧化碳向心透平气动性能研究

Study on Aerodynamic Performance of a Partial-Admission Supercritical Carbon Dioxide Radial-Inflow Turbine

基于给定的热力参数,设计了1台超临界二氧化碳向心透平,功率为75kW,部分进气度为0.3,并采用六面体结构化网格、有限体积法和RNGk-ε双方程湍流模型对该透平进行了详细的流场分析。结果表明,所设计的部分进气超临界二氧化碳向心透平输出功率达到73.25kW,效率为66.27%,基本满足设计要求。喷嘴及动叶流道的压力、温度及马赫数分布合理,表明设计方案可行。靠近喷嘴堵塞弧段壁面及动叶非进气弧段流动紊乱,旋涡多,熵增较大,存在明显的部分进气损失。

Based on the appointed thermodynamic parameters, a supercritical carbon dioxide radial-inflow turbine with power of 75 kW and partial-admission degree of 0. 3 was designed. A thorough flow field analysis was then performed adopting hexahedral structured grid, FEV method and RNG k-ε two-equation turbulence model. The result indicates that the power and efficiency of the designed turbine mainly meet requirements. Specifically, the output power is 73.25 kW and the efficiency is 66.27 %. The distributions of pressure, temperature and Mach number in nozzles and rotors of admission segment are reasonable, which demonstrates the feasibility of the design scheme. There exist turbulent flow and entropy production in non-admission part of the rotors and near the blocking segment wall of the nozzles, showing obvious loss of partial admission.