Velocity and Heat Transfer Studies of an Impinging Jet Using Magnetic Resonance Velocimetry and Infrared Thermometry

Abstract Heat transfer performance of a single cylindrical orthogonal jet impinging on a flat plate was obtained through steady-state infrared (IR) thermometry. One Reynolds (Re) number of 23,000 based on pipe exit diameter was considered. The distance of the jet exit plane from the shim varied from two to ten times the impingement jet diameter in increments of two diameters. The observed temperature and constant heat flux boundary condition allowed for the calculation of a Nusselt (Nu) number distribution to estimate the heat transfer performance of the impingement jet. At the smallest separation distance of two diameters, the relative maximum heat transfer performance is found at the stagnation point followed by a second peak occurring at a radial distance of approximately two diameters from the stagnation point. Compared to all jet exit separation distances studied, the distance of six diameters exhibited the greatest magnitude Nusselt number at the stagnation point. A paired fluids experiment using Magnetic Resonance Velocimetry (MRV) techniques collected hydrodynamic data of a single impinging jet at a matching Re number of 23,000 and jet exit plane distances. This work provides relevant data for correlation of impingement cooling design through unique analysis of the fluid mechanics and heat transfer characteristics of a single impinging jet. Measurement uncertainty was assessed to range from +/−1% to +/−10% for Nusselt number and +/−7% for velocity.