纵流式换热器壳程层流流动与传热的数值模拟

Numerical simulation of laminar flow and heat transfer in shellside of longitudinal-flow heat exchanger.

采用计算流体力学和数值传热学方法 ,对纵流式换热器的运行工况进行简化和假设 ,建立了壳程层流流动与传热的数学模型。为改进收敛性和提高计算精度 ,用算子分裂法和二阶时间精度离散格式等改进算法 ,用三维等参单元导出了离散化非线性控制方程组 ,编制了数值模拟程序。对纵流式换热器壳程的流场和温度场进行了数值模拟研究 ,得到换热器内流体流动状态和热流分布 ,并分析了支撑结构的参数变化对流体流动和传热的影响。数值计算结果和实验数据吻合较好 。

This article presents the mathematical model of laminar flow and heat transfer in shellside of the longitudinal-flow heat exchanger(LFHE), which is based on Computational Fluid Dynamics(CFD) and Numerical Heat Transfer(NHT) along with simplification and hypotheses about working conditions of LFHE. Arithmetic operator-split method and two order time precision discrete format are applied so as to improve astringency and calculating precision. The discrete nonlinear governing equations are educed with 3-dimension equal parameter element, and the numerical simulation program is developed. Flow field and temperature field in shellside of LFHE are simulated to obtain the fluid flow state and heat flow distribution. The influence of different parameter of the supporting structure on fluid flow and heat transfer is analyzed. The computed results are identical to the experimental data, and this means the model can effectively simulate fluid flow and heat transfer in shellside of LFHE.