蒸汽和空气预旋进气共转盘腔壁面换热研究

Study on Heat Transfer Performance of a Co-rotating Cavity with Pre-swirl Inflow of Steam and Air

为了研究不同冷却介质对燃气轮机预旋共转盘腔换热特性的影响,采用数值计算方法分析了空气和蒸汽2种介质下预旋系统共转盘腔表面的换热过程,对比了2种冷却介质在不同旋转雷诺数、无量纲质量流量和进口总温条件下的换热效果。结果表明:相同无量纲质量流量下预旋进气的转盘冷却效果优于无预旋;不同无量纲质量流量下,蒸汽对共转盘腔表面的换热效果均优于空气;旋转雷诺数在5.5×106~7.2×106内,相同旋转雷诺数下的蒸汽冷却下的转盘平均Nu比空气冷却提高约22%,低旋转雷诺数时2种冷却介质的冷却效果略优于高旋转雷诺数时;不同进口总温下,蒸汽冷却效果仍然优于空气,但随着进口总温的升高其优势逐渐减弱,转盘表面传热平均Nu随预旋进口总温的升高而减小。

To investigate the effects of different cooling mediums on the heat transfer performance of a gas turbine co-rotating cavity with pre-swirl inflow, a numerical analysis was conducted on the heat transfer process of the co-rotating disc cooled by air and steam in the pre-swirl system, so as to compare the heat transfer effectiveness of the two cooling ways at different rotational Reynolds numbers, non-dimensional mass flow rates and at different total inlet temperatures. Results show that the effectiveness of both air and steam cooling on the rotating disc with pre-swirl inflow is better than that without pre-swirl inflow un- der the same non-dimensional mass flow rate. The heat transfer performance of co-rotating cavity with steam cooling is superior to that with air cooling, under different non-dimensional mass flow rates. The average Nusselt number of steam cooling is 22G higher than air cooling at the same rotational Reynolds number ranging from 5.5X l0G to 7.2 X 106. For both the mediums, the cooling effect of rotating disc at low rotational Reynolds number is slightly better than at high rotational Reynolds number. At different to- tal inlet temperatures, the effectiveness of steam cooling is always better than air cooling, but the superi- ority weakens with the rise of total inlet temperature. The average Nusselt number of co-rotating cavity re- duces with the increase of total inlet temperature.