Thermal design method of bayonet-tube evaporators and condensers

Kayansayan N.

INTERNATIONAL JOURNAL OF REFRIGERATION-REVUE INTERNATIONALE DU FROID, vol.19, no.3, pp.197-207, 1996 (SCI-Expanded) identifier identifier


The paper describes an effectiveness-NTU design method of bayonet-tube evaporators and condensers. Including the effect of the wall superheat on the shell-side film coefficient, and using an energy balance on the tube, differential equations for the steady-state fluid temperatures are formulated. Because of the nonlinear nature of the governing equations, the fourth-order Runge-Kutta method is employed to the solution of the finite difference equations. The results are iterated with the combination of integration techniques. An upper bound to the numerical error being +/-5%, the fluid temperature distribution as well as the exchanger effectiveness are determined, anti presented as a function of the Hurd number, the number of heat transfer units and the flow arrangement. For flow entering through the inner tube, the temperature distribution displays the occurrence of a minimum at a point other than the tube-tip of the exchanger. In an extension of the analysis, an effort is made to illustrate the deviation of the results obtained by uniform film coefficient from the present study, and the differences are outlined. Copyright (C) 1996 Published by Elsevier Science Ltd and IIR