The Fluid Flow And Heat Transfer Characteristics In The Channel Formed By The Fins Having Staggered Ball Bumps And Ball Pits Of A Plate Fin Heat Exchanger

According to statistics, the 80% of primary energy consumption in the world needs to go through heat exchange equipment. This shows that the energy consumption of heat exchange equipment plays a key role in the overall utilization of energy. Because of its compact structure, high heat exchange area and high heat transfer coefficient are widely used in petrochemical, aerospace, locomotive and other industries. With the development of science and technology, the original flat fin plate fin heat exchanger can not meet the current needs of the industrial field. In recent years, many scholars have studied the zigzag plate fin heat exchanger, porous plate fin heat exchanger, the plate fin heat exchanger with other fins,such as the fin punched delta wing and other shape fins, and some remarkable results have obtained. Due to the slotted fin surface is easy to absorb dust, to overcome this defect, this paper addressed the plate fin for heat exchanger with the fins punch ball convexs/concaves.The sicentific base is that when the fluid flows through the fin and the ball, the ball on the surface of the fin and the spherical concave can generate longitudinal vortices that make the convection heat transfer enhancement.In order to obtain the flow and heat transfer characteristics of a plate fin heat exchanger, a numerical method is used. In which a periodic channel is selected as the calculation area. First the computational domain was meshed using three-dimensional infinite interpolation grid generation technique, and the grid system is smoothed and redistributed into a reasonable grid system, the denepdnece of the numerical results on grid size was strictly examined. The governing equations and the computational domain are transformed into coordinate transformation, and the governing equations are discretized into algebraic equations, and the numerical results are obtained by iterative solving the algebraic equations.The numerical method was used to study the effects of the ball convex and concave spherical radius, the intercepting ball convex and concave spherical height, the ball convex and concave spherical transversal spacing, the ball convex and concave spherical longitudinal spacing, the height of the channel on heat transfer and flow. The results were compared with the results plain fin channel.The results show that the longitudinal vortices can be generated by the spherical convex/ concave spherical surface, which makes the convective heat transfer capability of the fin surface significantly improved. Under the same Reynolds number Re, stamping the ball convex/concave spherical fin channel average Nusselt number than the straight fin channel high 47%~85%, but at the same time stamping the ball convex/concave spherical fin channel drag coefficient to than the straight fin channel high 102%~140% and the concave spherical will appear backflow phenomenon, the concave spherical convection heat transfer ability islow. In addition, ball convex/concave spherical radius, intercepting ball convex/concave spherical height S0, adjacent convex/concave spherical longitudinal spacing S2, and the transversal spacing of the adjacent ball convex/concave S1 have important influence on the rectangular channel convection.