A study of the effects of internal rib and channel geometry in rectangular channels. Part II. Heat transfer

Abstract

P Pc S wc U Y = transverse base dimension of a rib, in. = Blasius friction factor, 2.Ap.g;De/p.u2.D1, di-= rib frequency or distance between corresponding = gravitational constant, 32.2 ft.lb.,/lb.f sq. sec. = height of a rib or internal geometry, in. = coefficient in empirical correlation, ~p = K.ue = exponent in experimental correlation, Ap = U . U " = number of ribs in a transverse row succeeding n2 = number of ribs in a transverse row succeeding n1 = exponent in experimental correlation, N E~ = = Euler number, Ap.g,/p.u2, dimensionless = Reynolds number, De.u.p/p, dimensionless = pressure drop, Ib./sq.in. = lineal perimeter of a noncorrugated rib, in. = lineal perimeter of a corrugated rib, in. = average plate spacing for fluid flow, in. = lineal fluid velocity in channel, ft./sec. = transverse width of plate channel between gas-= plate separation or compressed gasket thickness, mensionless points of successive ribs, in. A . N R e -N kets, in. in. Greek Letters a p' p B r 6 = transverse rib angle for cross diagonal ribs, o ( = = exponent correlation for rib base angle effects = base angle of ribs, radians = coefficient correlation for rib base angle effects = exponent correlation for rib corrugation effects = coefficient correlation for rib corrugation effects = exponent correlation for plate separation effects 0, radians A E e x A p u 2 r T 4 $ = coefficient correlation for plate separation effects = exponent in empirical correlation, A p = K.u'= transverse rib angle for diagonal ribs, radians = exponent correlation for rib frequency effects = coefficient correlation for rib frequency effects = density of fluid, lb./cu.ft. = exponent correlation for rib shape effects = coefficient correlation for rib shape effects = exponent correlation for transverse rib angle ef-= coefficient correlation for transverse rib angle ef-= exponent correlation for protrusions = coefficient for protrustions = rib shape geometrical parameter, A d A T -1.0, ects fects dimensionless LITERATURE CITED 1. Troupe, RHeat transfer and pressure drop data were taken on commercial plate heat exchange equipment. Nusselt and Euler correlations were determined for each of the six commercial heat exchangers investigated. These correlations were combined to establish a single heat transferpressure drop relationship for any plate type of heat exchanger channel. The results of this investigation were tested by using the correlations developed in Part I of this series to predict pressure drop data for the commercial unit based on their channel geometries. These predicted pressure drops were then used with the results of this part of the series to predict and compare heat transfer data. The correlations developed in this work allow one to determine the heat transfer characteristics in a ribbed rectangular channel from the pressure drop characteristics of the channel in question.The effects of internal geometries on the pressure drop in ribbed rectangular channels have been correlated as functions of the rib and channel geometry in Part I of this seri...