Flow and Heat Transfer Prediction in Rotating Rectangular Pin-Fin Channels (AR = 10:1)

Abstract

Computations were performed to study the three-dimensional turbulent flow and heat transfer in a rotating narrow rectangular channel with staggered arrays of pin fins. The channel aspect ratio is 10:1, the pin length to diameter ratio is 1.0, and the pin spacing to hydraulic diameter ratio is 3.0 in both the streamwise (S L =D h ) and spanwise S T =D h ) directions. Various combinations of rotation numbers and coolant-to-wall density ratios were examined. A total of seven calculations have been performed with various rotation numbers and inlet coolant-to-wall density ratios. The rotation number and density ratio varied from 0.0 to 0.14 and from 0.1 to 0.40, respectively. The Reynolds number is fixed to 10,000. A finite volume code, FLUENT is used to predict the flow and heat transfer. The Reynolds stress model in conjunction with a two-layer model is used to compute the turbulent flow and heat transfer in the rotating channel. The computational results are in good agreement with experimental data. NomenclatureAR = channel aspect ratio Cp = specific heat, J=kg K D, d = pin diameter, m D h = hydraulic diameter, m H = pin length, m h = heat transfer coefficient, W=m 2 K k = thermal conductivity, W=m K L = length of the duct, m Nu = Nusselt number in fully developed turbulent nonrotating tube flow, hD h =k Nu 0 = Nusselt number, hD h =k R r = radius from axis of rotation, m Re = Reynolds number, W b D h = Ro = rotation number, D h =W b S= arc length, m S L = pin longitudinal pitch, m S T = pin transverse pitch, m T = local coolant temperature, K T i = inlet coolant temperature, K T w = wall temperature, K u, v, and w = the mean velocities in x, y, and z directions, respectively, m=s u m = maximum velocity between pin fins, m=s W b = bulk velocity, m=s = angle of channel orientation measured from direction of rotation, deg = = inlet coolant-to-wall density ratio, T w T i =T w = dimensionless temperature, T T i =T W T i = density of fluid, kg=m 3 = dynamic viscosity of the coolant, m 2 =s = rotational speed, rad=s