The Consequence of Target Surface Curvature in the Jet Impingement Cooling

Abstract:

An experiment sturdy has been carried out for jet impingement cooling on the spherically convex surface is the development of mechanism. The effect of curvature, Space between jet exit and target surface, and Reynolds number on heat transfer is investigated for around air jet on hemispherical surface. The flow at the jet exit has fully developed velocity profile. A uniform heat flux boundary is created on the heated surface. The experiments are performed for 5000<Re<25000, 2<L/d<10, and jet diameters ranging from 1.3, 2.1, 3.4, 4.0 and 5.2 cm. In the mean time effect of curvature on local heat transfer is negligible at the wall jet region corresponding to r/d>0.5. From the experimental results the variation of the D/d ratio with local Nusselt number (Nu_st) for various Reynolds numbers and various L/d ratios are plotted. The results show that Nu_st increase with increase in curvature and the effect of the curvature will high at high Reynolds number. i.e. Nu_st at Re=25000 is 25% higher than at Re= 5000 This may be attributed to an increase in curvature increases acceleration, & size of three dimensional counter rotating vortices at stagnation point and the increment of Reynolds number increases the jet momentum, and also enhances the vortices creation. Nu_st is peaking in the L/d ratio of 6 because of high turbulence intensity as this distance.

• Periodical: Applied Mechanics and Materials (Volumes 766-767)
• Pages: 1148-1152
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.766-767.1148
• Online since: June 2015
• Authors: M. Karthigairajan, S. Mohanamurugan, K. Umanath*
• Keywords: Air Jet, Curvature, Forced Convection, Impingement Cooling, Mechanics, Vortices

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