Abstract: In this work, the rotary heat exchanger for waste heat recovery of SCR (Selective Catalytic Reduction) low temperature denitration system in cement kiln is taken as the research background, and a typical heat transfer element in the rotary heat exchanger is selected as the base plate type. The structural improvement methods with different proportions of corrugated height and different corrugated inclination angle are proposed and a series of new-style heat transfer elements are obtained. The flow resistance and heat transfer characteristics of different heat transfer elements are compared and analyzed by three-dimensional numerical simulation method, and the area mass factor j/f is introduced to represent the comprehensive heat transfer performance of the heat transfer elements. The results show that under the same heat transfer condition, the flow disturbance at the boundary layer of the heat transfer element with the corrugated height proportion of 3:1 is gentler than heat transfer elements that of other corrugate height proportion. Therefore, its Nusselt number value is the smallest, the value of the friction coefficient is the smallest, but the area mass factor is the largest. This also proves that the heat transfer element after the adjustment of the corrugated height proportion has improved the comprehensive heat transfer performance compared with the original CU heat transfer element. Under the premise of a heat transfer element with the corrugated height proportion of 3:1, the inclination angle of corrugate is changed in the range of 30°~60°. It is found that, the greater the inclination degree of the heat transfer element, the stronger the flow mixing, the larger the value of the corresponding Nusselt number is, and the larger the value of the friction coefficient is, while the increase of the friction coefficient with the increase of the degree of corrugate inclination is greater than that of the Nusselt number. When the inclination angle of the corrugate is 30°, the comprehensive heat transfer characteristics of the heat transfer element are optimal. The results show that the structure improvement can improve the comprehensive heat transfer performance of flow heat transfer element.

Key words: heat transfer element, flow resistance characteristic, heat transfer effect, numerical simulation

摘要： 以水泥窑选择性催化中低温脱硝系统的余热回收设备回转式换热器为研究背景，选取回转式换热器中典型换热元件作为基础板型，提出波纹高度比例和斜波纹倾角的结构改进方式并得到了一系列新型换热元件。通过三维数值模拟方法对比分析不同换热元件的流动和传热特性，引入面积质量因子j/f表示换热元件的综合换热性能。结果表明，相同的换热条件下，波纹高度比例3:1的换热元件在边界处的流动扰动比其他波纹高度比的换热元件平缓，因此，其Nu最小，摩擦阻力系数f最小，但j/f最大，较原CU换热元件的综合换热性能提升。波纹高度比例3:1的换热元件的斜波纹倾角在30°~60°变化时，换热元件的倾角度数越大，流动混合越显著，Nu越大，f也越大，且f的增幅大于Nu的增幅，波纹倾角度数为30°的换热元件的综合换热特性最优。

关键词: 换热元件, 流动特性, 传热效果, 数值模拟