Choice of a turbulence grid and model to calculate the discharge coefficient of the standard orifice plate

The results of analyzing a flow in the measuring pipeline with a standard orifice plate within the range of 5×104 ≤ Re ≤ 108 using the computational fluid dynamics (CFD) methods are presented. A deviation of the design value of the discharge coefficient from the value indicated in the standard served as a criterion for choosing a turbulence model and grid. The calculation data for the discharge coefficient obtained with the use of RANS turbulence models are given and it is shown that the CFD methods make it possible to calculate the discharge coefficient of a variable-pressure drop flowmeter with a precision that meets the standard requirements.