局部进气裂解油气向心涡轮气动设计与轴向力分析

Aerodynamic design and axial force analysis of partial admission radial turbine with cracked fuel vapor

从涡轮结构形式的角度探究了油气涡轮轴向力平衡问题。建立了半开式、开式与闭式3种局部进气裂解油气向心涡轮,通过数值仿真对比分析了设计工况下3种油气涡轮的气动性能与轴向力,并归纳总结了非设计工况下总轴向力随压比的变化规律。仿真结果表明:半开式、开式与闭式油气涡轮的总体气动性能相近但轴向力表现有明显的差别。当涡轮压比发生变化时,开式油气涡轮轴向力稳定性最好,半开式油气涡轮轴向力稳定性最差,闭式油气涡轮轴向力始终是3种油气涡轮中最小的。由结果分析可知,当涡轮压比低于3时,应避免选用半开式油气涡轮,而涡轮压比变化较大时,则宜采用开式油气涡轮,此外,在采用闭式油气涡轮时需要轴承预留足够的轴向载荷裕度。

Axial-force balance of the cracked fuel vapor turbine was studied from the perspective of turbine structure.Partial admission cracked fuel vapor turbines with unshrouded,open,and enclosed impellers were established respectively,and the aerodynamic performance and axial force of turbines under the design condition were compared and analyzed by numerical simulation.Meanwhile,the variation law of the total axial force with pressure ratio under off-design conditions was summarized,which provided guidance and suggestions for the selection of cracked fuel vapor turbine structure forms.The simulation results showed that the aerodynamic performance of unshrouded,open,and enclosed turbines was similar,but the axial force performance was distinctive.When the pressure ratio changed,the axial force stability of the open turbine was the best,the unshrouded one was the worst,and the enclosed turbine axial force was the smallest among the three kinds of cracked fuel vapor turbines.The result analysis showed that when the turbine pressure ratio was lower than 3,the unshrouded turbine should be discarded;if the turbine pressure ratio changed greatly,the open turbine should be adopted.In addition,axial load of bearings should be sufficient when enclosed cracked fuel vapor turbines were exploited.