三叶孔板换热器热力性能及其影响因素分析

建立了三叶孔板换热器壳程周期性全截面模型，利用商用软件Fluent14.0及RNG k-ε湍流模型对8种不同结构参数的换热器壳程流体流动及传热性能进行数值模拟。分析了支撑板间距、三叶孔孔高、导流筒结构形式等结构参数对三叶孔板换热器传热及阻力性能的影响，并对比不同结构换热器的综合换热性能。结果表明：壳程传热系数与压力梯度都分别随着支撑板间距和开孔高度的增加而减小，且支撑板间距和三叶孔孔高对三叶孔板换热器壳程压降的影响大于其对传热的影响；六边形结构的导流筒换热器换热性能优于圆形导流筒换热器；8种换热器模型中，支撑板间距400mm、三叶孔高3.3mm（模型4-2）的换热器综合性能最好，支撑板间距400mm、三叶孔高1.8mm（模型2-2）的换热器综合性能最差。

Investigation of the effects of structural parameters on the thermal performance of heat exchangers with trefoil-baffles

This research established a simplified periodic model for the flow and heat transfer on shell side of heat exchangers with trefoil-baffles. Based on the RNG k-ε turbulence model，the flow and heat transfer characteristics on shell side were investigated by using commercial CFD software Fluent14.0 for 8 heat exchanger samples with different structural parameters. Effects of the structural parameters，including baffle pitch，trefoil-hole height and draft tube structure，on the performance of heat transfer and friction were analyzed. The results showed that the heat transfer coefficient and pressure gradient decreased when baffle pitch，as well as trefoil-hole height，increased. Baffle pitch and trefoil-hole height had larger influence on pressure drop than that on heat transfer coefficient. The heat exchanger with hexagon draft tube had better heat transfer performance than that with circle draft tube. The comprehensive performances were also evaluated. The Case 4-2（Lb=400mm，H=3.3mm）was best and case 2-2（Lb=400mm，H=1.8mm）was worst among all heat exchangers with different structural parameters.