Hybrid numerical method for transient analysis of two-dimensional pin fins with variable heat transfer coefficients

A hybrid numerical technique is used to investigate a two-dimensional cylindrical pin fin with arbitrary variable Biot numbers on the pin fin lateral and tip surfaces. By taking the Laplace transform with respect to time, the governing equation and boundary conditions are discretized by central finite difference then general solutions for dimensionless transient responses are obtained in the transform domain. A Laplace inverse technique is taken to achieve the inversion to the real domain. The transient distributions of temperature in the real domain are presented numerically. It is found that the variable Biot number can lead to an obvious temperature lagging effect base on the function of Biot numbers when pin fin immerses in variety physical environments. Moreover, the present method also can be applied to cases with different types of boundary conditions, such as time-dependent changes in boundary temperatures. (C) 2002 Elsevier Science Ltd.