1Centre for Energy Studies, JNTU College of Engineering, Hyderabad-500034, India.
2Department of Mechanical Engineering, SNIST, Hyderabad, India.
NomenclatureA
surface area of the resistor, m2
Cpspecific heat at constant pressure, J/(kg K)
ddiameter of nozzle, m
Hdistance between nozzle tip to resistor, m
Nulocal Nusselt number, Eq. (10)
Rejet Reynolds number, Vd/ν
qheat flux, W/m2
tcooling time, seconds
Tssurface temperature of the resistor before cooling,°C
T∞ambient temperature,°C
Vvelocity of air, m/sec
H/dnozzle-to-resistor spacing to nozzle diameter
NuONusselt number at stagnation point
Kthermal conductivity of air, W/(m K)
PrPrandtl number
rradial distance measured from the stagnation point, m
The objective of this work is to carry out an experimental study to examine the effect of geometric parameters on the confined impinging jet heat transfer characteristics of an array of electronic resistors with a single circular jet of different diameters. The effect of Reynolds number and aspect ratio H/d, on Nusselt number has been studied. Measurement of surface temperatures of the resistors is made in the range of 5850 < Red < 12200 and 2 < H/d <10 and heat transfer coefficients evaluated. Local heat transfer rate at a fixed radial location and stagnation Nusselt number for different H/d ratios were correlated and compared with the data of earlier investigators. This study can provide useful information to the application of impinging jet heat transfer in industry.
Jet impingement, air jet, Local heat transfer coefficient, Electronic cooling
