折流板换热器壳程流体流动与传热特性数值模拟

Numerical simulation of shell-side fluid flow and heat transfer in baffle heat exchanger

根据流体动力学和计算传热学理论,建立了折流板管壳式换热器计算模型,运用CFD技术对换热器壳程流体的流动与传热问题进行了三维数值模拟,得到了不同壳程进口雷诺数Re条件下换热器壳程流体的流场和温度场。对数值模拟结果进行分析,以总传热系数h,壳程总压降Δp以及单位压力损失下的传热系数h/Δp作为换热器性能的衡量标准,分析了不同折流板间距和不同折流板圆缺高度时管壳式换热器壳程总传热系数h、总压降Δp以及h/Δp随壳程进口雷诺数的变化规律。结果表明:随着壳程进口流速的增大,换热器壳程总传热系数和总压降增大、h/Δp减小;在壳程流体流量不变的情况下,结合单位压力损失下的传热系数h/Δp,适当减小折流板间距或减小折流板圆缺高度,可提高换热器的换热性能。

According to the theory of computational fluid dynamics and numerical heat transfer,baffle shell-and-tube heat exchanger calculation model is established.Based on CFD technology,the flow and heat transfer problems of the heat exchanger shell fluid are simulated with three-dimensional numerical methods.The flow fields and temperature fields of the heat exchanger shell fluid are obtained at different inlet Reynolds number.According to the numerical simulations,the variations of heat transfer coefficient h,pressure drop Δp,and the comprehensive performance factor h/Δp are obtained at different baffle spacing and different baffle round gap height with Reynolds number.The results show that the heat transfer coefficient h and the pressure drop Δp increases,h/Δp decreases with the shell inlet velocity increases.Under the condition of the constant flow of fluid in the shellside,it can improve the heat transfer performance of the heat exchanger that properly reducing the baffle spacing or reducing baffle round gap height by the comprehensive performance factor h /Δp.