Experimental study on heat transfer enhancement in the vertical nature convection by using delta‐winglet longitudinal vortex generators

This paper focuses on the study of heat transfer enhancement in natural vertical convection by using delta‐winglet longitudinal vortex generators. In the experimental range of Rayleigh numbers, the effect of attack angle, height, and width of the winglet of longitudinal vortex generator (LVG) on heat transfer performance was experimentally investigated. The results showed that there was an optimal attack angle and that the height and width can affect the heat transfer. In terms of array performance, it was shown that initial arrays could enhance the performance of later arrays. Moreover, the effects of LVG and low rectangular fins were compared. The results showed that the effect of LVGs was greater than that of low rectangular fins. © 2006 Wiley Periodicals, Inc. Heat Trans Asian Res, 35(6): 402–409, 2006; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.20126     

板料成形接触摩擦过程有限元模拟

在对板料成形过程中的接触摩擦进行有限元模拟时，为了取得可靠的计算结果，需要准确地描述模具与板料之间的动态接触状态。本文在全面分析成形中板料与模具接触边界动态变化的基础上，结合ABAQUS有限元分析软件给出了模型的几何描述、接触算法选择及应用VFRIC用户子程序来进行接触摩擦模型的建立等具体方法。并通过具体实例，证明了这些方法应用于板料成形过程的接触摩擦分析的可行性。