Optimum louver angle design for a louvered fin heat exchanger

Abstract

This paper suggests a method for finding the optimal louver angle of a fin heat exchanger by use of a simplified conjugate-gradient method (SCGM) and a three-dimensional computational fluid dynamics model. The search for optimum louver angles ranging from θ = 15 o to 45 o for suitable louver pitches and fluid input velocity are carried out for Reynolds number Re H (based on the fin spacing 1.5 mm and the frontal velocity 1 to 5 m/s) ranging from 100 to 500. The area reduction of using louver surface relative to the plain surface is the objective function to be maximized. The model calculates optimum performance of the heat-exchanger by means of finding the fin angle which would give the biggest reduction in area of the louvered surfaces relative to plain fin surfaces required to give equivalent performance. The numerical optimizer adjusts the angle of the louvered fin toward the maximization of the performance of the heat exchanger. Additionally, the correlations of the optimal louver angle as function of Reynolds number Re H are obtained.

Pressure Drop and Heat Transfer Characteristics of Louvered Fin Heat Exchangers

“…Experimental studies aimed at obtaining the suitable louvered fin geometries tend to be costly and time consuming because of the large number of geometrical parameters involved for instance, louver angle, louver pitch, louver length and fin spacing. Hence, numerical studies are probably a more viable option for conducting a parametric study and investigating the effect of various parameters [2,7]. In this study, numerical method using commercial CFD code ANSYS 14.0 is employed for various geometrical parameters in order to determine the pressure drop and heat transfer rate of louvered fin heat exchanger.…”

“…Heat exchangers are used in a wide variety of applications. Typical among them are the district heat stations, heating, ventilating, air-conditioning, and refrigeration (HVACR) systems, food and chemical process systems, and heat recovery systems [1,7]. The advantages of placing louvers on the fin is to provide additional heat transfer surface area and to interrupt the growth of the boundary layer forming along the fin surface.…”

“…At low Reynolds number values, realignment would be slight, but at high Reynolds number it was almost complete. However, in standard louvered fins, the change in flow behavior is due to the flow following the path of least resistance or in other words, the path corresponding to the lowest overall pressure drop [1,4,7,8].…”

Fluid Dynamic Simulation and Optimization of Compact Heat Exchangers with Louver Fins

“…By turbulence be a phenomenon of dissipative nature in terms of energy, the heat exchange is further enhanced within the exchanger. For the analysis was used the heat exchanger tested and simulated in [2] who performed experimental tests and the heat exchanger studied by [5] which performed a fin efficiency analysis through numerical simulation. On the front and back of the fluid domain (computational geometry) are added volumes to stabilize the flow in the inlet and outlet sections.…”