ABSTRACT

When the vehicle cooling system works in negative gauge pressure environment of plateau, it will face the problem of reduced heat transfer performance, which will lead to an increase in vehicle energy consumption. So, there’s important meaning in studying the thermal-hydraulic performance of heat exchangers and optimizing the design of which for negative gauge pressure environments. In this article, experimental study of wavy fin heat exchanger is carried out in negative gauge pressure environment, and then the numerical simulation model is established. The effects of fin size parameters (fin pitch, fin height and fin amplitude) on the temperature field and flow field distribution of wavy fins are studied. Empirical correlations of Colburn j factor and Friction factor f are obtained according to 336 groups of numerical simulation results. The heat transfer coefficient of air side at −44kPa negative pressure is decreased by 34% on average compared with atmospheric pressure, and the friction factor f is increased by 61.5%. The average deviations of correlations for j and f are 2.3% and 2.7%, respectively. The results could be used in engineering practice of design and optimization of wavy fin heat exchangers for vehicle cooling systems operate in plateau environment.

摘要

汽车冷却系统在高原负表压环境下工作时，会面临传热性能下降的问题，从而导致整车能耗增加。因此，研究负表压环境下换热器的热工水力性能及其优化设计具有重要意义。本文在负表压环境下对波浪翅片换热器进行了实验研究，并建立了数值模拟模型。研究了翅片尺寸参数（翅片间距、翅片高度和翅片振幅）对波浪翅片温度场和流场分布的影响。Colburn j因子和摩擦因子f的经验相关性根据336组数值模拟结果得到。-44kPa负压空气侧传热系数比大气压平均降低34%，摩擦系数f提高61.5%。j和f的相关性平均偏差分别为 2.3% 和 2.7%。研究结果可用于高原环境车辆冷却系统波浪翅片换热器设计优化工程实践。