Transient Heat Conduction In Semi Infinite Solids With Temperature Dependent Properties

Transient Heat Conduction in Semi-Infinite Solids with Temperature Dependent Properties

Similarity solutions are obtained for the transient heat conduction in a semi-infinite solid with temperature-dependent thermal properties. The surface of the solid is considered subjected to a time-varying boundary condition, either heat flux Q sub w = a t to the bth power or temperature T sub w = t sub 0(1 + t to the b*th power). Solutions for the temperature distribution and the local heat flux are presented. In particular, type 420 stainless steel, whose thermal properties are strong functions of temperature, was chosen for analysis to demonstrate the significance of the effect of the temperature dependence of thermal properties on heat transfer calculations. Keywords: Transient heat conduction; Semi-infinite solid; Temperature dependent properties; Time varying boundary condition; Similarity transformation; Similarity solution.

An Integral Approach to Transient Heat-conduction Problems with Phase Transition

An approximate method for studying transient heat-conduction problems is presented. Its application to various linear problems and nonlinear problems involving phase transitions is described by means of several idealized problems. The method is basically a refined version of the well-known Karman-Pohlhausen integral technique in boundary-layer theory, and represents a further development of the basic ideas previously exploited to calculate skin friction and heat transfer in boundary-layer flows. The approximate solutions obtained are extensively compared with existing exact solutions and those of the classical Karman-Pohlhausen method. From the simplicity and accuracy of the present method as demonstrated in the results, the potential utility of the method in providing simple, engineering solutions to complex aerodynamic heating problems can be inferred.

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