Analysis of flow through an orifice meter: CFD simulation

Orifice meters are the most common instruments used for fluid flow measurement because of its ruggedness, simple mechanical construction and other known advantages. Orifice coefficients are empirical because of difficulty in accurately predicting the effects of geometrical complicacy and flow separation from the wall on the flow. In the present paper, Computational Fluid Dynamics (CFD) simulation has been used to predict the orifice flow with better accuracy. CFD simulations have been performed using OpenFOAM-1.6 solver and validated with the published experimental data of Nail (1991) and Morrison et al. (1993). CFD simulations have been validated with pressure drop and energy balance of our experimental data of water as fluid. The outcomes of the CFD simulations in terms of profiles of velocity, pressure, etc. are discussed in detail. A new scheme has been proposed to track vena-contracta with the help of CFD and with a suitable provision in the hardware of orifice meter. The new scheme maintains the existing advantages of orifice meters and provides better accuracy and sensitivity.

► Flow features of an orifice meter have been simulated using CFD.
► Complete energy balance has been established.
► CFD is proposed as a cost effective tool to estimate discharge coefficient (CD).
► A scheme has been proposed to position pressure tap at vena-contracta to measure flow with better accuracy and sensitivity.