CFD study on mixing by coupled jet-impeller mixers in a large crude oil storage tank

Investigation of RC-DTH air hammer performance using CFD approach with dynamic mesh method

Reverse circulation down-the-hole (RC-DTH) air hammers have been widely used in construction and mining activities owing to their high drilling efficiency and good dust control performance. This paper presents a computational fluid dynamics (CFD) approach with the dynamic mesh method for evaluating the performance of RC-DTH air hammers. Nine stages of operating conditions of the RC-DTH air hammer are described herein to better understand the operating mechanism of the RC-DTH air hammer. Dynamic layering, sliding interfaces, as well as user-defined functions were employed to update the mesh in dynamic mesh modelling. The influences of rebound coefficient, input air pressure, and piston mass on the performance of RC-DTH air hammers were studied. It was found that increasing the rebound coefficient and input air pressure can improve the impact performance of RC-DTH air hammers, whereas increasing input air pressure can reduce energy efficiency and increase energy consumption. In addition, simulation results indicate that increasing the input air pressure may increase the stroke of the piston; the piston mass should be optimally selected to match the designed geometric parameters to avoid a significant drop in performance. The CFD approach with the dynamic mesh method shows superiority in evaluating the performance of RC-DTH air hammers.

Mathematical modeling of large floating roof reservoir temperature arena

The current study is a simplification of related components of large floating roof tank and modeling for three dimensional temperature field of large floating roof tank. The heat transfer involves its transfer between the hot fluid in the oil tank, between the hot fluid and the tank wall and between the tank wall and the external environment. The mathematical model of heat transfer and flow of oil in the tank simulates the temperature field of oil in tank. Oil temperature field of large floating roof tank is obtained by numerical simulation, map the curve of central temperature dynamics with time and analyze axial and radial temperature of storage tank. It determines the distribution of low temperature storage tank location based on the thickness of the reservoir temperature. Finally, it compared the calculated results and the field test data; eventually validated the calculated results based on the experimental results.