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Abstract
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Flow measurement is found in a large variety of industries and for different types of fluids. Orifice flow meters are widely used for measuring the flow rate in pipelines due to its small size in the piping system and ability to output the flow rate with satisfying accuracy. The main problems with the orifice flow meter are the unrecoverable pressure loss and due to the shear forces exerted from the orifice walls onto the flow, inaccurate flow rate measurement as well as the vortex shedding behind the orifice. Numerical studies will be performed using the CFD code to investigate the flow through a circular square edged orifice with various thicknesses and diameters inside a pipe. The discharge coefficients for the different orifice characteristics at different Reynolds numbers will be determined. Simulations are performed in two different regimes, a laminar flow regime at 0 ≤𝑅𝑒 ≤ 400 and a turbulent flow regime at 2 500 ≤ 𝑅𝑒 ≤ 40 000. The effects of different 𝑅𝑒, 𝛽 and 𝑡 on the flow characteristics will be discussed by presenting the stream wise velocity contours, streamlines and 𝑄-criterion contours.
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