平面叶栅尾流板开孔率对跨声速涡轮叶栅流道影响的数值分析

跨声速平面叶栅风洞中通常通过尾流板来改善平面叶栅周期性,针对尾流板的设计需求,利用数值模拟的方法,研究了尾流板在15%、30%、50%开孔率下对实验叶栅的影响。数值分析结果表明:叶栅尾缘激波在自由边界上反射后,返回到叶栅通道中,破坏了叶栅通道的周期性；开槽尾流板减少了反射波对叶栅通道的影响,减弱叶栅尾缘激波的反射波强度,在某特定情况下能使反射波变成膨胀波,从而提高了叶栅通道周期性；尾流板开孔率为15%时能极大地改善平面叶栅通道的周期性,相对于开孔率为50%时叶栅的周期性误差降低约16.43%。 

Numerical study on the effect of the linear cascade slotted tailboard void ratio on the passage of transonic gasturbine cascade

Transonic test in linear cascade wind tunnel usually uses a tailboard to improve the linear cascade periodicity. In order to meet the tailboard design requirement, a tailboard with void ratios of 15%,30%,50% was designed and optimized with a numerical method to attenuate such effects. The numerical results indicated that, shock waves stemming from the cascade trailing edges reflected back to the passages at the boundaries disturbing the interior flow and breaking periodicity of cascade passage. A substantial attenuation of such interference was obtained via use of a slotted tailboard downstream the blade trailing edge. Meanwhile, the reflected wave strength was different from the impinging one, and under certain conditions, the reflected wave can become an expansion wave, as a consequence, the pitchwise periodicity had a considerable improvement. The 15% tailboard void ratio significantly improved the periodicity of the cascade flow, reducing the periodicity error by 1643% in related to the 50% void ratio tailboard.