水蒸气含量对高温平板气膜冷却传热影响研究

Steam Concentration Effects on the Heat Transfer of a Film-Cooled Flat Plate at High-Temperature

IGCC系统中新一代先进燃气轮机透平通流部分处于高温高湿的工作环境,因此其内部流动存在固有的复杂的流热耦合问题。为指导燃气轮机透平叶片冷却系统设计必须开展对流热耦合问题的试验与数值研究。本文在一平板气膜冷却流热耦合实验台上开展了模拟新一代燃气轮机透平通流部分高温高湿工作条件的流热耦合机理研究,并进行了数值模拟。研究工作表明:高温高湿条件下,辐射换热对总体换热特性影响十分显著,因此在通过试验和数值手段研究流动、对流换热和辐射换热多场耦合问题时必须合理考虑辐射换热的影响;本文还给出了通过数值手段模拟辐射换热问题的简化边界建模方法,并提出了中心线总体冷却效率和主流水蒸气摩尔分数及流向距离之间的拟合关系式。

The flow paths of advanced turbines operating in IGCC systems are in a high-temperature and high-steam-concentration condition,therefore the corresponding flow physics possess an inherent and complex flow and conjugate heat transfer characteristics.Both experimental and numerical investigation on the flow and conjugate heat transfer mechanism are essential for the design of gas turbine cooling systems.In this paper,the author conducted a conjugate heat transfer study utilizing a high-temperature flat-plate film-cooling experimental facility,which can imitate the high-temperature and high-steam-concentration working condition of advanced turbines.Numerical studies corresponding to experiment were also conducted.The following conclusions were drawn from studies：under high-temperature and high-steam-concentration conditions,thermal radiative heat transfer plays an important role on the overall heat transfer characteristics,therefore effects of radiation under these conditions should be taken into consideration properly;This paper also presented a simple method for radiative boundary condition modelling and proposed the correlation relation between center-line overall cooling effectiveness and mole fraction of steam and dimensionless stream-wise distance.