MONTE CARLO BASED UNCERTAINTY ANALYSIS FOR VARIABLE PROPERTY MIXED CONVECTION FLOW IN A UNIFORMLY HEATED CIRCULAR TUBE

摘要

A Monte Carlo based stochastic numerical analysis of simultaneously developing mixed convection laminar flow and heat transfer with variable properties in a uniformly heated circular tube was carried out. The Monte Carlo simulations were performed for heating of a large Prandtl number liquid for a wide range of Prandtl numbers (50 <= Pr <= 1000), Rayleigh numbers (10(5) <= Ra <= 10(7)), and nondimensional heat flux values (100 <= q(w)d/k <= 1000). The results show that the effect of uncertainties in the properties is greater on the friction factors uncertainty than it is on the Nusselt numbers uncertainty, and the uncertainty of the predicted friction factors and Nusselt numbers increases with increasing free convection and entrance effects. The maximum uncertainties in the predicted friction factors and Nusselt numbers were around 7.5% and 3.3%, respectively, for a 10% uncertainty value in the fluid properties. The uncertainties in the friction factors and Nusselt numbers were found to increase approximately linearly with increasing fluid property uncertainties.