Laminar Free Convection Heat Transfer From Isothermal Spheroids: A New Dynamic Model

Accurate calculation of free convection heat transfer from isothermal bodies is of fundamental importance in science and engineering. In the present article, a new analytical model is developed to calculate laminar free convection heat transfer from isothermal oblate and prolate spheroids of arbitrary eccentricity. It is based on the new concept of Dynamic Body Gravity Function. This function is introduced, explained and modeled by use of simple expressions. A new dimensionless parameter Body Fluid Function is introduced and applied in this model. Numerical solutions are also obtained to compare with the available experimental data and to examine the accuracy of the proposed model. Results of this dynamic model for five different spheroids (oblate, sphere and prolate) are compared with the present numerical solution and also the available experimental works. Excellent agreement between analytical, numerical and experimental results shows that this simple method, accurately predicts Nusselt number in a wide range of Ra for all spheroids under consideration.

Keywords:

Free convection , Spheroid , Dynamic model