Augmentation of Heat Transfer from Upward Circular Impinging Water Jet

抄録

An exprimental study on heat transfer of upward impinging circular water jet system shows the influence of the height of supplementary water with a view to improving heat transfer at the stagnation point. Optimum heights of supplementary water which brings about the augmentation of heat transfer are S⁄D=2 for H⁄D=10, and S⁄D=1 for H⁄D=20—50. For the single phase forced convection heat transfer, generalized correlations that include the effects of nozzle—to—heated surface distance and the height of supplementary water were found by using modified Nusselt number, Reynolds number at each nozzle diameter. Nu⁄Pr^0.4=C•Re^m•ε, ε=1.0+α(S⁄D)^β And for H=24cm, dimensionless correlation was found to be N_{UH/⁄Pr^0.4=C•ReH^1.27 (D⁄H)ⁿ for 0≤S⁄D≤3, Vo=3.5−8.29m⁄s and D=4−8mm^φ.}