A Numerical Investigation for Heat Transfer Enhancement Using Convergent and Divergent Shape Orifice Geometry of Synthetic Jet

A synthetic jet is a flow technique and mostly useful for cooling applications. In a synthetic jet, actuator fluid is moved in and outside a cavity, from a small orifice, by the continuous oscillation of a diaphragm. A numerical study of an electronic cooling module employing a periodic jet flow at an orifice is represented in this paper. Numerical simulations are carried out using ANSYS Fluent software and for modelling of a diaphragm, a moving wall boundary condition is applied using a user-defined function. Based on standard k-ε turbulent, dynamic mesh model, and PISO algorithm, numerical simulation of the 2D, viscous, unsteady synthetic jet model is proposed. Here, an average heat transfer coefficient is determined for varying axial distance amongst the orifice exit and heated surface and validated with existing experimental results. Also, the average ejection and suction velocities are validated for a given actuation frequency. Additionally, the heat transfer performance of synthetic jet for divergent-shaped orifice and the convergent-shaped orifice is investigated. It is observed that a diversion-shaped orifice has the highest heat transfer enhancement. A heat transfer enhancement of approximately 14% over that of round orifices was observed.