Heat transfer for laminar thermally developing flow in parallel-plates using the asymptotic method
Heat transfer for laminar, thermally developing flow in parallel-plates is investigated using the asymptotic method. There are two asymptotes for local, and mean Nusselt numbers (Nuz and Num) in the parallel-plates thermal entrance problem at both uniform wall temperature (UWT) and uniform heat flux (UHF). The first asymptote corresponds to very small value of dimensionless axial coordinate (z∗). The second asymptote corresponds to very high value of dimensionless axial coordinate (z∗). Using the methods discussed by Churchill and Usagi (1972, “General Expression for the Correlation of Rates of Transfer and Other Phenomena,” AIChE J., 18(6), pp. 1121–1128), the fitting parameter in the proposed model can be determined. Comparisons of the asymptotic model with the analytical and numerical solutions available in the literature are presented.
Axial heat conduction effects in the entrance region of laminar duct flows: Correlations for the local Nusselt number
Abstract Axial heat conduction effects within the fluid can be important for duct flows if the Prandtl number is low (liquid metals) or if the hydraulic diameter of the channel is very small (micro-channels). Exact analytical solutions for the extended Graetz problem for such situations are well known and documented in literature. In the present paper suitable correlations are developed for the local Nusselt number in the thermal entrance region in a parallel plate channel and in a pipe. Correlations are given for different thermal boundary conditions and for axial positions before (x   0) the jump in wall temperature or wall heat flux.
Analytical investigation of fully developed laminar-flow forced convection heat transfer in rectangular ducts with uniform heat flux
Thesis (M.S.) Massachusetts Institute of Technology. Dept. of Naval Architecture and Marine Engineering, 1957.