有机工质在透平静叶栅内流动的数值研究

Numerical simulation of organic flow in static turbine cascades

针对有机工质在透平中流动产生气动损失的问题,对有机工质R245fa在SC11静叶栅中的流动进行了数值研究。提出了考虑粘性的有机工质物性定义方法,分别采用理想气体状态方程和SW气体状态方程对透平静叶栅中的流场进行了研究,对比了采用不同气体状态方程得到的压缩因子及密度沿叶型表面的分布规律,评价了有机工质在透平静叶栅内流动的非理想程度。分析了有机工质在透平静叶栅内流动的参数分布,并得到了有机工质在静叶栅内不同区域的膨胀规律。研究结果表明,应用理想气体状态方程与SW气体状态方程得到的计算结果偏差很大,理想气体状态方程不适用于有机工质在透平内流动的计算;在透平静叶栅中,叶片压力面压降幅度较吸力面更平缓,吸力面下游马赫数达到最大值,叶片尾迹中存在损失。

Aiming at the problem of aerodynamic loss generated by organic flow in turbine, the inflow characteristics in SC11 static cascade using R245fa was numerically studied. Definition methods of properties for viscous organic fluid were proposed. Adopting state equation of i- deal-gas and SW equation, the flow fields of static blades utilizing numerical simulation method were respectively analyzed. Different variations of compressibility factor and density along the cascade path using different equations were compared. The extent of non-ideal state of organic flow in static turbine cascade was evaluated. The distribution of organic flow parameters were analyzed, and expansion rules of different regions in static cascade were obtained. The results indicate that there are big deviations of parameters using ideal-gas equation of state com- pared with SW equation, so ideal-gas equation is no longer applicable in numerical simulation of organic flow in turbine. In static turbine cascade, pressure drop amplitude on pressure side is more smooth than that in blade suction surface. Mach number appears the max value in the downstream of the suction surface. Loss exists in the wake of the blade.