СРАВНИТЕЛЬНЫЙ АНАЛИЗ РАЗЛИЧНЫХ МОДЕЛЕЙ ТЕЧЕНИЯ ПРИ ЧИСЛЕННОМ МОДЕЛИРОВАНИИ ВИХРЕВОГО ТЕЧЕНИЯ В ДОРОЖКЕ КАРМАНА

Abstract

This paper considers the question of the applicability of models of laminar and turbulent flows to describe the process of vortex formation in the vortex flowmeter. A reliable calculation of the flow structure in the area of the laminar and transition to turbulent flow allows to solve fundamental questions about the possibility of detecting the vortices at low speeds, as well as to explore the problems of stability of vortex formation at low speeds. This would, in turn, extend the range and improve the accuracy of measurement of vortex flowmeters. The methods of computational fluid dynamics in the determined velocity distribution of single-phase flow in the flow standard for the bluff body vortex flowmeters. The calculations were performed on models of laminar and turbulent flow for a wide range of speeds of 0.15 m/s to 5.6 m/s, typical of vortex flowmeters. As a model of the turbulent flow, a combined nizkoreynoldsovskaya SST (Shear Stress Transport) model Menter. A comparison of flow patterns produced in two models. To assess the reliability of the simulation results were compared calculated parameters frequency ripple in the stream with the experiments carried out on the meter DRS.M-25A.The frequency characteristics of the flow in the model calculations were determined by means of a discrete Fourier analysis. The findings of the simulation frequency compared with experimental data on the dependence of the frequency of the vortices on the flow rate. The estimation of discrepancies in the results of calculation and experiment for each model flow. It is shown that the model of turbulent flow shows the best degree of coincidence of the calculated and experimental data over the entire range of flow rates. The structure of the stream received by the model SST at high speeds, in good agreement with the experimental data. At low speeds, SST model gives a higher accuracy rate fluctuations flow compared with the model Laminar.