Cooling time estimation on rotating high temperature cylinder using CFD technique and verification through Analytical method

Conjugate Heat Transfer study is carried out on a large rotating high temperature cylinder to estimate cooling time using Computational Fluid Dynamics (CFD) technique. Objective of the study is to estimate lowest time required to cool the cylinder from high temperature (750°C) to desired surface temperature (100°C) maintaining specified temperature differential between mean to surface on the rotating cylinder. To achieve the objective, it is proposed that cooling nitrogen gas flows axially through annulus surrounding on the rotating cylinder to cool down to desired temperature. The conjugate heat transfer study is proposed with five different combination of rotational speed, cooling gas pressure and axial velocity of fluid to determine the interdependence between the heat transfer mechanism and the structure of the secondary flows. Particular interest is the accurate prediction of the heat transfer from the cylinder to the flow field using CFD technique. An empirical formula is proposed on the rotating system to estimate cooling time maintaining specified mean to surface cylinder temperature. Surface and mean temperatures estimated by CFD simulation study are compared with analytical method.