orifice flow

About this project

The project simulates the flow of water through an orifice. The water is assumed to be incompressible and the k-omega SST turbulence model is used as the large pipe diameter and inlet velocity of 2 m/s is likely to result in a turbulent flow and so using a laminar flow model would lead to incorrect results. It is possible to calculate the degree of turbulence via the Reynolds number. The results show that a jet forms after the orifice, and the water attains a maximum velocity of 5.9 m/s. The orifice causes a low pressure region to form directly after the orifice. The pressure in the low pressure region falls to below the pressure and the outlet of the pipe. The jet leaving the orifice drives a toroid shaped vortex around the edges of the pipe. In the vortex region, the flow recirculates with minimal exchange of liquid. The orifice causes a large pressure drop, much larger than would occur if the entire length of pipe were of the diameters of the orifice.