Response of a two phase system subject to oscillations induced by the motion of its support structure

Abstract

In many parts of the world, seawater desalination offers one of the most promising alternatives for supplying the required potable water, The desalination is an energy intensive process and use of nuclear reactors as the energy source for desalination is an attractive option. To ensure reactor safety for a barge-mounted plant, multiple systems for removing heat from the core even after the nuclear reactor is shutdown, need to be provided. One of the Residual Heat Removal Systems (RHRS) has to be energy independent and hence has to be based on the principles of natural circulation, A three-loop energy independent RHRS, in which the second loop is working in two-phase, is described, The barge will be invariably subjected to oscillations due to seawater movements. The RHRS should be able to perform its intended functions even when the barge is oscillating. If the natural frequency of oscillations of the RHRS is close to the frequency of oscillations of the barge, resonance may occur and lead to deterioration of heat removal capability. Hence, it is necessary to determine the natural frequency of oscillation of such a system, Temperature and quality distribution of the working fluid required for the estimation of natural frequency of the system is calculated by solving momentum balance and energy balance equations for the loops of the RHRS. Various terms of the governing equation describing oscillatory behaviour of non-isothermal, two-phase closed loop system are derived. The overall equation is solved using fourth order Runge-Kutta method. The response of the system for various initial conditions is computed.