Chapter 6 Fundamentals of Convection Momentum and Heat Transfer Analogies 6-47C Reynolds analogy is expressed as x L x f C Nu 2 Re , = . It allows us to calculate the heat transfer coefficient from a knowledge of friction coefficient. It is limited to flow of fluids with a Prandtl number of near unity (such as gases), and negligible pressure gradient in the flow direction (such as flow over a flat plate). 6-48C Modified Reynolds analogy is expressed as 3 / 1 , Pr Nu 2 Re − = x L x f C or H p x x f j C h C ≡ = 2/3 , Pr 2 V ρ . It allows us to calculate the heat transfer coefficient from a knowledge of friction coefficient. It is valid for a Prandtl number range of 0.6 < Pr < 60. This relation is developed using relations for laminar flow over a flat plate, but it is also applicable approximately for turbulent flow over a surface, even in the presence of pressure gradients. 6-49 A flat plate is subjected to air flow, and the drag force acting on it is measured. The average convection heat transfer coefficient and the rate of heat transfer are to be determined. Assumptions
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This note was uploaded on 01/22/2012 for the course PHY 4803 taught by Professor Dr.danielarenas during the Fall '10 term at UNF.