Experimental and numerical study of natural convection heat transfer from arrays of zigzag fins

Abstract

In this study natural convection heat transfer from arrays of zigzag fin is studied numerically and experimentally. The length and width of the fins are L = 75 mm and H = 25 mm. Fin thickness and fin spacing are t = 2 mm and s = 6 mm, and zigzag arrangement is made with different pitches along the rectangular fins length. Finite volume scheme is used to solve three-dimensional equations of laminar flow and heat transfer numerically. For ten different zigzag fin geometries, both constant temperature and constant heat flux boundary conditions at the base plate are examined numerically and results have been compared with solid rectangular fin array. Rectangular and zigzag fin arrays with 4 and 14 triangles are made and tested experimentally at different heat inputs, and air flow field and natural convection heat transfer rate for each case are determined. Experiments are done in a thermally insulated room with specific equipment to control test conditions and measure necessary data. Results of experiments and numerical solutions are compared for various power input. By comparison with solid rectangular fin, 22 triangles zigzag fin array has the same heat transfer but with 50% reduction in mass for constant base temperature. For experiments for different input power, natural convection heat transfer coefficient of 4 triangles zigzag fin array is increased 36%–50% in comparison with solid rectangular fin array with 50% reduction in mass.