Experimental validation of heat/mass transfer analogy for two-dimensional laminar and turbulent boundary layers
- Citation data:
International Journal of Heat and Mass Transfer, ISSN: 0017-9310, Vol: 113, Page: 84-95
- Publication Year:
- Physics and Astronomy; Engineering; Chemical Engineering
Heat and mass transfer from a solid surface into a fluid stream are both diffusion driven processes. Their constant property mathematical model equations are identical for identical flow and equivalent boundary conditions, when Lewis number is equal to unity. Problems with engineering applications can be transformed from one domain to the other for practical and economic advantages. Mass transfer measurement using naphthalene sublimation can be faster, of higher resolution, economical, and more accurate than a direct heat transfer measurement. The diffusion rates by heat in air and naphthalene in air are quantitatively different. Hence, the advantages of naphthalene sublimation measurement are justified when the heat/mass transfer analogy is experimentally and/or analytically verified and an analogy factor (F = Nu / Sh ) is determined. Heat/mass transfer analogy is experimentally verified in this study for two dimensional laminar and turbulent boundary layer flows over a flat plate. A thermal boundary layer technique is used to measure local heat transfer coefficient ( Nu ) and a naphthalene sublimation measurement is used to evaluate local mass transfer coefficient ( Sh ) for two similar plates subjected to the same boundary layer flow. The heat/mass transfer analogy factor is calculated using the measured Nu and Sh. It is found to agree with the analytical prediction of 0.677 within 2% for the laminar case and is found to be constant at 0.667 for the turbulent flow.