Numerical analysis of heat transfer on a rotating disk surface under confined liquid jet impingement

The objective of this study is to characterize the conjugate heat transfer for a confined liquid jet impinging on a rotating and uniformly heated solid disk of finite thickness and radius. The model covers the entire fluid region (impinging jet and flow spreading out over the rotating surface) and the solid disk as a conjugate problem. Calculations were done for a number of disk materials and working fluids covering a range of Reynolds number (500-1500), under a broad rotational rate range of 0-750 rpm or Ekman number (4.42 x 10(-5) to infinity), nozzle to target spacing (beta=0.25-5.0), disk thicknesses to nozzle diameter ratio (b/d(n)=0.167-1.67), Biot number (3.73 x 10(-3)- 0.118), Prandtl number (1.29-124.44), and solid to fluid thermal conductivity ratio (36.91-2222). It was found that plate materials with higher thermal conductivity maintained a more uniform temperature distribution at the solid-fluid interface. A higher Reynolds number increased the local heat transfer coefficient reducing the wall to fluid temperature difference over the entire interface. The rotational rate also increased local heat transfer coefficient under most conditions. The simulation results compared reasonably well with previous experimental studies. (c) 2006 Elsevier Inc. All rights reserved.