The Relationship Between the Distributions of Slot-Jet-Impingement Convective Heat Transfer and the Temperature in the Cooled Solid Cylinder

Abstract

A conjugate heat transfer investigation was conducted to better understand the effects of an impinging radial slot jet cooling device on both the heat transfer rates and temperature fields in the fluid, and especially in the cylindrical solid cooled by this device. The study used numerical methods to model a configuration in which a set of four radially positioned slot jets cooled a cylindrical steel target using air with a jet Reynolds number of 20,000. A steady-state v ² f Reynolds averaged Navier-Stokes model was used with a representative two-dimensional section of the axisymmetric target and flow domain. Boundary conditions, heat intensity, target wall thickness, and thermal conductivity were varied to study the effects of the impingement cooling on the temperature distribution in the solid. For Biot (Bi) numbers between 0.0025 and 0.073, temperatures in the solid were clearly affected by lateral conduction, and temperature variation in the solid was an order of magnitude smaller than the variation in the surface heat transfer coefficient. For the case of constant heat flux, the area-weighted standard deviation in the solid temperature was found to correlate well with the dimensionless parameter Z ≡ Bi(d/t _eq)², where d is the cylinder diameter and t _eq is the equivalent wall thickness, and a correlation equation was developed.