Conservation equations for mass and momentum with a two equation k–ε model are solved for the continuous phase along with a discrete phase particle modeling (representing gas bubbles) in the RH degasser to predict the circulation flow rate of water in a scaled down model and then the numerical solution has been extended to the real plant case for the prediction of steel circulation flow rate in the actual RH vessel. The prediction of the circulation flow rate of water from the present numerical solution matches reasonably well with that of the experimental observation, taking into account various uncertainties those have been imbedded in the numerical model. RH operation for multi up legs and single down leg for a water model shows that the circulation flow rate falls with the number of up legs and there is an optimum number of down legs for which the circulation flow rate is the maximum for the case of a single up leg. For the actual RH operation in plant it was seen that the circulation flow rate increases with the increase in snorkel diameter and snorkel immersion depth (SID). However, it is apparent that there is existence of optimum SID for maximum circulation flow rate. For different down leg immersion depth the circulation flow rate in the RH depends heavily on the up leg immersion depth. The actual RH operation of the plant for the multi up leg and down leg cases was found to be exactly similar in nature to that of the water model cases.