球突翅片的传热流动特性及等效热阻数值分析

为了提高翅片管换热器的传热系数和减小压降,提出了一种球突型翅片,通过数值模拟研究其传热与流动性能,同时应用(火积)耗散理论对其传热的不可逆性进行分析。计算结果表明:与平片相比,其传热能提高26.21%～39.53%,而阻力系数仅提高16.62%～27.04%,同时综合性能增加16.54%～32.56%;这说明该翅片具有高传热系数低压降的特点,是一种性能优良的翅片。通过(火积)耗散分析可以看出:球突翅片的等效热阻减小,其传热的不可逆性减弱。

Numerical Analysis of Equivalent Thermal Resistance and Heat Transfer Flow Characteristics of Dimpled Fin

Low pressure drop and high heat transfer coefficient are the mainly goals for any new fin shape design.The dimpled fin was presented,Numerical study investigation was applied to investigate the characteristic of air flow and heat transfer.In the meantime,the irreversibility of the convective heat transfer was analyzed based on the entransy dissipation concept.The computational results show the Nusselt numbers of dimpled fin is 26.21%39.53% higher than that of plain fin,while friction factors of dimpled fin is 16.62%27.04% higher than that of plain fin,in the meantime overall performance of dimpled fin is 16.54%32.56% higher than that of plain fin;these indicate the dimpled fin has excellent performance and the characteristic of high heat transfer and low pressure drop.By analysis of entransy dissipation can be seen that the equivalent thermal resistance in the dimple fins is less.Therefore,the irreversibility of heat transfer in the dimple fins decreased.