Numerical Simulation of the Effect of Surface Roughness on the Throttling Characteristics for Multi-stage Pressure Reducing Valves

Abstract

AbstractThe multi-stage pressure reducing valves are increasingly used in technical engineering fields such as residual oil hydrogenation. The overall performance of the valve can be affected by a numbers of factors, and the effect of roughness is still not fully understood. Using computational fluid dynamics technology, the influence of roughness on the throttle characteristics of the spool of a series multi-stage pressure-reducing regulating valve is studied. Under the same inlet velocity condition, numerical simulation of different roughness is carried out, and its influence on the internal flow of the series multi-stage pressure reducing valve is analyzed. The findings depict that the maximum pressure difference in the valve and the friction pressure difference increase with the increase of the roughness and after 2 mm, the increase decreases with the increase of the relative roughness, and finally gradually stabilizes; the average velocity at the valve outlet and the average internal velocity decrease progressively with the increase of roughness, and the relationship is approximately linear; at the roughness of 1 mm, the maximum wall shear stress is 5.6 times that when the roughness is 0 mm. In addition, the flow resistance coefficient increases linearly with the increase of roughness. The research results can provide theoretical support for the structural design of the series multi-stage pressure reducing valve.KeywordsMulti-stage pressure reducing valvesRoughnessThrottling characteristicsFlow resistance coefficientComputational fluid dynamics