HEAT TRANSFER FOR LAMINAR SLIP FLOW OF A RAREFIED GAS BETWEEN PARALLEL PLATES WITH UNSYMMETRICAL WALL HEAT FLUX

摘要

An analysis has been made to determine the effects of low-density phenomena on the forced convection heat-transfer characteristics for fully developed laminar flow in a parallel plate channel for unsymmetrical heating involving a constant heat flux along each of the walls. Consideration is given to the slip-flow regime wherein the major rarefaction effects are manifested as velocity and temperature jumps at the channel walls. The results obtained apply along the entire length of the channel. The solution contains series expansions, and analytical expressions for the complete sets of eigenvalues and eigenfunctions are presented. The results give the wall temperatures and the thermal entrance lengths for the channel for various mean free paths and wall heat flux ratios. The results indicate that, in general, the thermal entrance length is decreased with increasing gas rarefaction and also that for a given mean free path the thermal entrance length is greater for unsymmetrical heating than for a symmetrical wall heat flux. Extension of the results is made or indicated to account for less frequently considered slip effects such as wall shear work, modified temperature jump, and thermal creep velocity.