Assessment of Three Diaphragm Modeling Methods for a Synthetic Jet: Heat Transfer Investigation

An investigation of unsteady flow and heat transfer from an axisymmetric impinging synthetic jet positioned on a constant heat flux disc is presented. Synthetic jet is a jet usually produced by oscillating a diaphragm placed on a cavity bridging an orifice. The continuity and the unsteady incompressible Navier- Stokes equations are solved using air as the working fluid. Also, the v 2  f turbulence model is applied as a suitable model for problems with stagnation points. Solution of the governing equations under the assumptions of incompressible, axisymmetric andtemperature-dependent properties is carried out. The PISO algorithm is employed for the coupling of continuity and momentum equations. In order to simulate the diaphragm oscillation, three different methods are examined. To ensure that the results are independent of grid and time-step size, the problem is solved with two grid sizes and three different time-step sizes. The present results show that setting a definite amount for inlet thermal boundary condition in blowing cycle can cause an error in prediction of cooling. This inaccuracy can be adjusted by modeling the whole cavity and orifice.