NUMERICAL ANALYSIS OF THE PERFORMANCE CHARACTERISTICS OF CONICAL ENTRANCE ORIFICE METER

Orifice meters are one of the most widely used flow meters in industrial applications due to their simplicity, accuracy and economy. However, the sharp edge orifice plates cannot be used for low Reynolds number flows, due to a large variation in discharge coefficient with Reynolds number. Conical entrance orifice plates are developed for this purpose. In the present study, a CFD methodology using ANSYS, FLUENT software has been ad opted for analyzing flow through conical orifice plate assemblies. The methodology has been validated by analyzing flow through standard orifice plate assembly (as per ISO 5167). K - ω SST model is found to be best suited for this class of problems.. The flo w is assumed to be steady and axisymmetric and the fluid is incompressible and Newtonian. The computed values of discharge coefficient and other parameters are in excellent agreement with the values given BS 1042 as long as operating conditions are within the specified range. The parametric study has demonstrated that the acceptable range of Reynolds number can be extended to 50 to 10 6 as compared to 80 to 80000 as specified by BS 1042.Pipe roughness does not have significant effect on the value of discharg e coefficient. The minimum acceptable pipe diameter is 10mm for these types of orifice plates. Quantitative data on pressure loss coefficient are also presented in the thesis. The study has demonstrated that a validated CFD methodology can be used to accur ately predict the performance characteristics of conical entrance orifice plate even under non standard conditions