A Numerical Study of a Single Unsteady Laminar Slot Jet in a Confined Structure

With the inherit advantages of air cooling, jet impingement can produce a factor of two or higher heat transfer than conventional fan flow over bodies. Therefore, impinging jets can solve a number of electronics thermal issues. Those jets produce complex flow and thermal structures leading to non-uniform and non-monotonic profiles on target surfaces. A numerical study is performed to investigate the flow and heat transfer characteristics of an unsteady laminar impinging jet emanated from a single high-aspect ratio rectangular (slot) nozzle in a confined arrangement. The spacing between the target plate and the nozzle is such that the jet would still be in its potential core length as it was in a free axial jet. Following the initial transients, flow and heat transfer parameters still vary considerably in time that the instantaneous and time-averaged values of surface profiles are not identical. Instantaneous surface pressure distributions exhibit that the stagnation point translates periodically around the initial jet-symmetry line and the surface profiles demonstrate off-center (non-stagnation point) peaks.