平直-波纹翅片椭圆管外空气流动与传热特性的数值研究  

Numerical Study of Air Flow and Heat Transfer Characteristics on the Outside of Combined Plane-wavy Fin-and-oval Tube

作　　者：阴继翔[1] 马建宗 武广剑 高源 

机构地区：[1]太原理工大学电气与动力工程学院,太原030024 [2]深圳和泰源材料科技有限公司,深圳518057

出　　处：《太原理工大学学报》2015年第4期455-460,共6页Journal of Taiyuan University of Technology

基　　金：国家自然科学基金面上项目:日光温室动态热湿环境作用下土壤-空气换热器热湿传递规律及数理模型研究(51476108);山西省自然科学基金资助项目:翅片管换热器结构参数对流与换热性能影响的机理研究(2012001024-4)

摘　　要：利用三维稳态湍流数值模拟方法,研究了物性参数为常数的空气在波纹翅片椭圆管和4种不同结构参数的平直-波纹复合翅片椭圆管换热器翅片间的换热与流阻特性,揭示了空气进口流速(或雷诺数Re)、平直-波纹复合翅片中波纹段占有比例以及所处位置对翅片表面平均努塞尔数Nu、压差损失Δp和翅片管综合换热性能因子j/f影响的规律。结果表明,复合翅片中波纹段所处的位置对换热强度的影响显著,但对流动压降(Δp)的影响甚微;复合翅片中波纹翅片所占比例的多少是影响Δp的关键因素;翅片宽度方向平均Nu(x)的变化主要发生在翅片起始段,不同结构翅片末段的Nu(x)值相差很小,但此处的波纹翅片却会使总压降增加,即翅片末段宜采用平直翅片;几种翅片椭圆管换热器的综合性能j/f均有最佳值产生,起始段为6个波长波纹翅片与末尾段为8个波长的平直翅片形成的复合翅片椭圆管换热器的综合性能最佳。研究结果将对翅片管换热器的选型设计提供理论指导。A 3-D steady and turbulent numerical simulation was employed to investigate the flow and heat transfer characteristics of air, having constant properties, in fin-and-oval tube heat exchangers with wavy fin or wavy-plain combined fin. The investigation reveals the effect of air inlet velocity or Reynolds number （Re）, wavy fin proportion and location in the combined fin on the average Nusselt number （Nu） of the whole fin surface, the pressure loss（△p） and the coeffi- cient of performance （j/f）. It is found that, within the studied Re range, the wavy location in conbined fin has a significant influence on the Nu, but has little effect on the △p; however, the wavy fin proportion is a key factor for the Ap. The change of average Nusselt number in the width direction（Nu（x）） along flow direction occurs mainly at the fin leading edge,and the Nu（x） has a smaller difference at the fin rear section for different fin configurations. So it is more suit- able to locate plain fin to the rear section rather than wavy fin, which can further reduce the pres- sure loss penalty while maintains the enhanced heat transfer. For all studied objects, the optimum j/f can be achieved. The finned oval tube heat exchanger with a combination of 6 wavelength wavy fin and 8 wavelength plain fin arranged along flow direction has maximum j/f value.

关 键 词：平直-波纹翅片 椭圆翅片管 局部换热特性 综合性能系数 

分 类 号：TU832.3[建筑科学—供热、供燃气、通风及空调工程]