A 3D Numerical study of Fluid flow through Circular Orifice flow Meter Via various Turbulence Models

Orifices are one of the common flowmeter for fluid flow measurement in industrial piping. Selection the suitable turbulence model has very important to achieve good accuracy of flow measuring in numerical simulation. This paper describes numerical simulation of the flow through a circular orifice in pipe by using computational fluid dynamics (CFD) with various turbulence modeling. Therefore the orifice in pipe is simulated in Ansys CFX 15 on 3D mode and different turbulence models such as standard 𝑘 − 𝜀, 𝐵𝑆𝐿, 𝑆𝑆𝑇 and 𝐵𝑆𝐿 𝑅𝑆𝑀 are employed. Via comparison of these results with experimental data and some valid numerical results, it can be found that the standard 𝑘 − 𝜀 model is the best agreement with experimental data. Also discharge coefficient of orifice is compared with standards ISO 5167 and ASME with about five percent error. In this model, maximum velocity is occurred downstream of orifice at distance of nearly one-time diameter of orifice hole. In this section the velocity of fluid is more than four times of the velocity at inlet the pipe.