WALL HEATING EFFECT ON LOCAL HEAT-TRANSFER IN A ROTATING 2-PASS SQUARE CHANNEL WITH 90-DEGREES RIB TURBULATORS

The influence of wall heating condition on the local heat transfer coefficient in a rotating, two-pass, square channel with 90-degrees transverse ribs on the leading and trailing walls was investigated for Reynolds numbers from 2500 to 25000 and rotation numbers from 0 to 0.352. Three thermal boundary condition cases were studied: (A) all four walls at the same temperature, (B) all four walls at the same heat flux, and (C) trailing wall hotter than leading with side walls unheated and insulated. The results for case A show that the ribbed wall heat transfer coefficients with rotation increase by a factor of two to three over the smooth wall data with rotation. As rotation number (or buoyancy parameter) increases, the heat transfer coefficients on the first pass (outflow) trailing wall increase and on the first pass leading wall decrease. The reverse is true for the second pass (inflow). The heat transfer coefficients on the first pass leading and second pass trailing walls for cases B and C are 50% higher than those for case A.