Numerical Investigation of Laminar Natural Convection Heat Transfer From an Isothermal Body: Concave vs. Convex Shapes

Abstract

In this article a numerical simulation is employed to obtain dimensionless heat transfer in laminar natural convection condition for isothermal bodies which are similar to sphere and cylinder. Then, the numerical results for different bodies are compared with each other to figure out the effect of convexity / concavity on laminar natural convection. A computational fluid dynamics (CFD) codes is used for solving the relevant mathematical expressions for natural convection heat transfer from isothermal bodies. Excellent agreement between the results of the present numerical simulation and available experimental results is observed in the whole laminar flow range 0≤RaA≤108. However, that is why the laminar natural convection from sphere and cylinder with L/D = 1 and a few other shapes turned out to be the same, some of the bodies show better natural convection behavior with specific shapes. In addition, Convexity has small effect on the Nu number for low laminar range of RaA number besides, in convex bodies, removing the sharp edges helps to increase natural convection heat transfer. Finally, it is worth to mention that this numerical simulation reveals that it has the capability to be used as a tool to predict the behavior of flow and heat transfer around isothermal convex / concave bodies.