Analytical and numerical study of instability of supercritical water flowing upward in two heated parallel channels with wall thermal energy storage effects

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Ghadge, Dhanashree
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The wall thermal energy storage effects on supercritical thermal hydraulic instability were investigated using a 1D-Linear frequency domain solution and 3D- Non-linear ANSYS CFX solution. Experimental cases of supercritical upward flow in two heated parallel channels were analysed. The one-dimensional (1D) analyses were done with two different wall thicknesses using uniform and non-uniform power distributions. It was found that the inclusion of wall thermal energy storage effects gives better prediction of thermal hydraulic instability in these two heated parallel-channel cases, which contradicts the conclusions of previous studies with wall thermal energy storage effects. Accurate prediction of the period of oscillation was also obtained. The 3D- numerical solution with wall also gives an excellent agreement with the experiments, for the instability boundary. A common CFD assumption; namely, circumferentially symmetric flow, was found to be inadequate. Temporal and grid independence was ensured for the reported cases. The predictions of period of oscillation obtained with the non-linear 3D ANSYS CFX code are discussed. Additionally, non-dimensional parameters were derived for the conversion of experimental data from one fluid to another in a given test facility and validated using 1D- linear solution.
Supercritical, Non dimensional parameters, SCWR, Thermofluid, CFD, Wall heat effects
Ghadge D., and Chatoorgoon V.. 2018. “Analytical Study of Supercritical Water Flow in Two Heated Parallel Channels with Wall Heat Effect.” In London, UK.