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为了改善涡轮和发动机的匹配,采用计算流体动力学(CFD)方法研究了脉冲进气条件下脉冲频率、脉冲振幅、喷嘴角度以及涡轮转速对可变喷嘴涡轮非定常性能的影响.研究结果表明:脉冲频率为80Hz时涡轮瞬态最低流量比40Hz时提高了10.4%,瞬态最低效率增加了4.7%,效率滞后现象更加明显;低脉冲振幅为25kPa时涡轮通流能力和效率迅速恢复,并且指出在低脉冲振幅时采用稳态设计是可行的;喷嘴角度为32°时,涡轮脉冲进气与稳态进气两种情况下的流量差异比喷嘴角度为10°时增加了3.3%,效率差异则增加了6.6%.涡轮内部脉动强烈,涡轮通流能力和效率下降明显;涡轮转速为47 256r/min时脉冲进气造成的流量和效率变化分别比30000r/min时相应值高了2.9%和0.8%,高转速时涡轮内部流场易受到进口条件影响,涡轮流量、效率以及攻角与稳态情况偏离大.
In order to improve the match between turbine and engine, CFD method was used to study the influence of pulse frequency, pulse amplitude, nozzle angle and turbine speed on the unsteady performance of variable nozzle turbine.The results show that: When the pulse frequency is 80Hz, the minimum transient flow rate of turbine is 10.4% higher than that of 40Hz, the transient minimum efficiency increases 4.7% and the efficiency hysteresis is more obvious. When the pulse amplitude is 25kPa, the turbine flow capacity and efficiency recover quickly, Steady-state design is feasible at low pulse amplitudes. When the nozzle angle is 32 °, the difference in flow between turbo-pulsation and steady-state intake is 3.3% greater than the nozzle angle of 10 °. The difference in efficiency The flow rate and efficiency of pulsed intake air at turbine speed of 47 256 r / min were respectively 2.9% and 2.9% higher than that of 30000 r / min respectively 0.8%. Turbine internal flow field is susceptible to import conditions at high revs. Turbine flow, efficiency and angle of attack and steady-state deviate greatly.