Laminar Forced Convection in the Entrance Region Between Parallel Flat Plates

Interferometer measurements of laminar forced convection to air in the entrance region between parallel flat plates are reported. Experimental local and mean Nusselt numbers are given for Reynolds numbers from 300 to 1500 and length-to-plate spacing ratios from 2 to 8. The experimental data are compared with corresponding values from theoretical analyses of simultaneously developing momentum and thermal boundary layers for the two cases considered: Air heated by both plates with the same uniform temperature, and air heated by one plate with a uniform temperature and other insulated. Equations are also given which summarize the theoretical results.