高温多组分工况下气膜冷却及TBCs传热特性

Heat Transfer Character of Film Cooling Combined With TBCs in Hot and Multi-Composition Gas Condition

煤基联合循环电站系统的燃气轮机透平将会工作在高温高湿的环境中。文中基于高温多组分气膜冷却试验台,分析在高温气膜冷却系统中导热/对流/辐射多场耦合作用机理.研究表明,高温环境下辐射作用不可忽略,不同的高温气体组分将对透平传热产生影响;随着主流高温燃气中水蒸气和二氧化碳体积分数之和每增加7%,平板上表面中心线总体冷却效率降低约0.02;TBCs在各组分工况下都有明显的温降效果,且燃气的水蒸气含量越高,温降效果越明显。由于辐射在高温高湿工况下的综合作用,在透平的设计中必须综合考虑不同燃气组分在导热/对流/辐射耦合作用下的气膜冷却传热机理。

Turbine used in the coal-based power generation system would work in hot and wet environment.The article analyses conjugate heat transfer mechanism coupled conduction/convection/ radiation.The work is based on a highly thermally loaded film cooling test rig which considers different hot compositions of gas.The research shows that radiation cannot be neglected in hot and wet condition,and different hot gas composition would affect the heat transfer in turbine.Overall effectiveness on the centerline of plate surface decreases about 0.02 with the volume fraction of CO_2 and steam increase per 7%.TBCs has obvious cooling effects in all gas composition condition, which is more serious in wet condition.Because of the combined effects of radiation in hot and wet condition,the thermodynamics of the film cooling system coupled conductive/convective/radiative heat transfer in the multi-composition hot gas may play an increasingly important role in the future turbine technology and design.