考虑组分扩散的气冷涡轮气热耦合计算(英文)

Coupled Heat Transfer Simulations of an Air-cooled Turbine Taking Account of Gas Component Variation

研究了冷气掺混过程中燃气组分变化对气冷涡轮气热耦合计算的影响。求解器为HIT-3D气热耦合求解器,该求解器包含一个流动求解模块与固体温度场求解模块,并通过直接耦合方法来实现流固区域的数据传递。为了研究冷气组分变化的影响,该求解器还求解了冷气组分扩散方程,并将工质热物性质,包括定压比热与气体常数,表示为组分与温度的函数。研究算例为某低压气冷涡轮导叶,同时进行了考虑组分扩散与单工质气体的气热耦合计算。对两种不同计算条件下的工质热力参数以及涡轮表面热负荷进行了比较,结果表明考虑工质组分变化后,在冷气掺混区域,工质气体常数变化很小,但定压比热与叶片表面温度有较大的差异;其中前者降低,后者升高,其最大差值分别为0.1和0.02。

The effects of the coolant mixing induced gas components variation on the vane thermal load predictions are investigated. Firstly a coupled solver HIT-3D is developed. The solver is consisted of an N-S （Navier- Stokes） solver and a thermal module, and the direct coupling method is utilized to accelerate the CHT （Couple Heat Transfer） simulation. A coolant diffusion equation is additional solved to the N-S equations to model the multi-component fluid flow induced by coolant mixing, and the fluid thermal properties are functions of both the gas component and temperature. Then CHT simulations of different working substances, pure gas and gas-air mixture, are carried out, and an air-cooled turbine vane with two cooling air channels and a slot at the vane trailing edge are served as the test case. Finally the thermal parameters and the vane thermal loads predicted by such simulations are compared with each other. It shows that taking account of the gas components variation, at the cooling air mixing region in the passage, the value of gas constant changes slightly, but the constant-pressure specific heat and the blade profile temperature change rather greatly, with the maximum decrement and increment up to 0.1 and 0.02 respectively.