抄録
A compact analytical expression is obtained for the asymptotic overall mass or heat transfer coefficient in double flow mass or heat exchanger systems. The analysis is based on the integral equation for the trans-wall flux. The solution obtained in this paper is shown to be equivalent to one of the generalized eigenvalue problems proposed by Nunge, Gill and Blanco. Moreover the characteristic equation derived in the asymptotic analysis determines the eigenvalue spectrum of the mutual boundary value problem. This method can be similarly applied to co-current and counter-current systems. Various velocity profiles including non-Newtonian flows can be treated by the series expansion method.