Design optimization of synthetic jet parameters for effective heat transfer

Abstract

The thesis deals with the average heat transfer characteristics of various orifice configurations and multi-orifice synthetic jet impingement on a heated flat plate. This study aimed to experimentally investigate the shape of the multi orifice configurations (circular, elliptical, and mixed) to maximize the heat transfer rate at a given surface spacing. It is found that a single elliptical orifice exhibits better performance at lower surface spacing, whereas the single circular orifice outperforms the elliptical orifice at high surface spacing. These initial results motivate a combination of the elliptical and circular orifices in a multi-orifice configuration to optimize the heat transfer rate at a given surface spacing. In this direction, four configurations of multi-elliptical and three configurations of mixed (combination of circular and elliptical) orifice are considered for the experiment. The maximum heat transfer is obtained with multiple elliptical configuration E-VC-(4H-4V)S (all elliptical (E) orifices having major axis vertical ellipse at the center(VC), 4 satellite (S) orifices having major Axis horizontal (4H) and other 4 having major Axis vertical (4V)) is 6% greater than that of SC (single circular orifice). Additionally, mixed configuration M-CC-(4C-4HE)S (mixed orifices (M) having a circular orifice at the center (CC), 4 circular satellite orifices (4C) and other 4 elliptical having major Axis horizontal (4HE)) consists of 15% higher heat transfer compared to SC configuration. The result indicates a strong correlation between orientation and the combination of satellite orifices in multi-orifice synthetic jet impingement heat transfer. The finding can be used for the thermal management of synthetic jet-based electronic equipment. Keywords: Multi-orifice, Synthetic jet, elliptical- orifice, Thermal management, Vibrating heated surface.