Effects of baffle configurations on the performance of a potable water service reservoir

Abstract

Because a baffle is a device used for altering the flow pattern in a tank, the use of a baffle wall was considered to modify an existing potable water service reservoir operating as a storage tank to achieve better water quality. Therefore, it is of great interest to study the effects of baffle configurations on the performance of the service reservoir. With the advancement of computational science and resources, a Computational Fluid Dynamics (CFD) method has become a reliable alternative to flow and tracer tests. Adopting dynamic meshes, this study investigates the effects of baffles, located at various locations, on the flow pattern and chlorine concentration distribution of a potable water service reservoir in Singapore during the refilling phase. The results of this study show a dual effect of the baffles located at the flow recirculation region. On one hand, it can break up the vortex to shorten the flow path. On the other hand, the velocity magnitude of the fluid is reduced after flowing past the baffle, because of the impact and viscous forces induced by the baffle. These two effects are contradictory to one another in enhancing the performance of the service reservoir acting as a storage tank, because short flow path and high velocity magnitude is preferred to achieve better water quality. The overall effect of baffling is found to be counter-productive in this feasibility study. The results also demonstrate the importance of studying the effects of baffle configurations under dynamic flow condition. © 2012 American Society of Civil Engineers.