工业供热中汽汽再热器换热强化数值研究

Numerical study on heat transfer enhancement of steam reheater in industrial heating

为了强化工业供热中的汽汽换热,通过CFD技术对不同类型换热管的流动及换热特性进行了研究。结果显示:光滑壁面时管壁两侧的高、低温蒸汽的温度梯度沿着流向逐渐变化,对流换热逐渐增强;相比于光滑管,采用内波节管和内螺纹波节管时,高温蒸汽侧的温度梯度增大,而低温蒸汽侧的壁面温度梯度明显增大;采用壁面异型结构能够改变管壁内温度梯度,采用内螺纹波节管尤甚。采用内波节管和内螺纹波节管的平均Nu相比于光滑管显著提高,最大值分别提高了26%和30%。

In order to enhance the heat transfer of steam reheater in industrial heating,the flow and heat transfer characteristics of different types of heat exchange tubes were studied by CFD technology.The results show that the temperature gradient of high and low temperature steam on both sides of the pipe wall changes gradually along the flow direction when the wall is smooth,and the convective heat transfer turns stronger.Compared with smooth tube,the temperature gradient of high-temperature steam side increases,while that of low-temperature steam side increases obviously when using internal corrugated tube and internal grooved corrugated tube.The temperature gradient inside the tube wall can be changed by adopting special-shaped wall structure,especially by using internal grooved corrugated tube.Compared with the smooth tube,the average Nu of the internal corrugated tube and the internal grooved corrugated tube is significantly increased,and the maximum value is increased by 26%and 30%respectively.