套管换热器对流换热的数值模拟研究

Numerical Simulation Investigation of Heat Transfer Performance in Double-pipe Heat Exchanger

本文建立了一种复杂的数学模型用于预测套管式换热器内流体的流动及传热特性。数学模型包括计算流体力学模型和计算传热学模型。其中,计算传热学模型中的湍流扩散系数是利用温度方差t2和温度方差耗散率εt来求解,而不是利用通常采用的Pr数假设值或实验测定值来求解。为验证新建立模型预测结果的准确性,本文将数值模拟结果与文献中的实验结果进行了比较,结果吻合较好。

A complex computational heat transfer model is proposed in this study to simulate the liquid flow and heat transfer in a double - pipe heat exchanger. The feature of the proposed model is able to predict the temperature as well as the veloeity distribution at once in a double - pipe heat exchanger with- out assuming the turbulent Prandtl number, or using the experimentally measured turbulent heat transfer diffusivity. The present model consists of the heat transfer equation with its auxiliary closing equations and the accompanied formulations of computational fluid dynamics （CFD）. In the mathematical expres- sion for the heat transfer equation, the newly developed temperature variance ~and its dissipation rate 6, equations are adopted for its closure. To test the validity of the present model, simulations were made for a double -pipe heat exchanger. The simulated results were compared with the published experimental da- ta and satisfactory agreement was found between them in temperature distributions.