A reliable analytical method applied to heat transfer problems associated with insulated cylindrical tanks

In this study, the heat transfer characteristics of insulated cylindrical tanks are analyzed by using a numerical method and three one dimensional analytical methods, namely the RPSWT (Regular Polygon top Wedge Thermal resistance), PWTR (Plane Wedge Thermal Resistance) and the conventional models. It is found that in the situation of shorter cylindrical tanks where the ratio between height and radius H/R2 < 10, the errors generated by the RPSWT model are positive in most cases, with only a few exceptions, and the errors generated by the conventional model are negative in all cases. Thus, a new CRPSWTC model is proposed, which combines the RPSWT and conventional models with appropriate proportion factors to neutralize the positive and negative errors. The combination allows the new model to obtain very accurate results in comparison with the numerical solutions within this H/R2 range. Nevertheless, the CRPSWTC model is proven to be applied to cases with larger H/R2 and still obtain satisfactory results. Alternatively, the RPSWT model obtains the best results when 10 ≦ H/R2 < 16, while the PWTR model returns better solutions when H/R2 ≧ 16.