Numerical Simulation of Natural Convection in a Transient Short-Hot-Wire Thermal Conductivity Cell

Abstract

Numerical simulations are performed for thermal and flow fields in a transient hot-wire thermal conductivity cell designed for the study of hydrogen gas at pressures up to 100 MPa. Two-dimensional unsteady incompressible Navier-Stokes equations are solved simultaneously with the continuity and energy equations. For hydrogen at atmospheric pressure, natural convection is found to have an almost negligible effect on the predicted wire temperature. At high pressures the onset of natural convection effects is predicted to occur in less than one second in agreement with an existing empirical correlation for the critical time for natural convection in a transient hot-wire cell.