Papers by Author: Majid Ali

Abstract: In nuclear power plant (NPP), particulate matter and gaseous pollutant release into the environment in severe accidents. To prevent from this disaster, filtered vented containment system (FVCS) containing venturi scrubber is being installed. The present work herein is the CFD simulation of throat pressure in venturi scrubber. A commercial software ANSYS CFX tool has been selected for this research. Euler-Euler regime is used to get the picture of behavior of fluid dynamics inside the venturi scrubber. Gas and liquid interact with each other in throat section of venturi scrubber. The pressure at the throat is one of the important factors to analyze the performance of venturi scrubber. In order to verify the results, mesh independency is checked. CFX and experimental results show good agreement with each other. The results obtained from CFX simulation are useful to improve the venturi design.

Abstract: Venturi Scrubbers are used in filtered vented containment system (FVCS) for collection of aerosols produced in NPP in severe accidents. Therefore, venturi scrubber (VS) needs an attention to design it properly and improved in all aspects. In this research, CFD simulations of prediction of pressure drop in venturi scrubber has been carried out. ANSYS CFX tool is used to obtain the simulation results. k-ε turbulence model is employed to study the fluid dynamics of the venturi scrubber. Mesh size plays an important role for convergence and accuracy of results. Therefore, the mesh independency is checked for optimized mesh size.

Abstract: Thermal stratification effects have been a great concern in a pressurizer surge line of pressurized water reactor (PWR) since 1988. These effects may damage the structural integrity and contribute in reducing the operational life time of pressurizer surge line. Several nuclear power plants operators have so far reported such mechanical damages. To realistically assess the structural integrity of pressurizer surge line subjected to thermal stratification, it is necessary to analyze the transient temperature distribution. Several researchers and scholars have carried out considerable efforts to determine the temperature distributions in the pressurizer surge line. In this study, an effort has been made to simulate the behavior of thermally stratified flow and predict the transient temperature distributions in the pressurizer surge line realistically. To obtain realistic results for such complex geometry of pressurizer surge line 3D analysis is performed using CFX commercially available CFD software. The transient temperature distributions obtained are presented and discussed.