Venturi Wet Gas Flow Modeling Based on Homogeneous and Separated Flow Theory

Abstract

Wet gas metering is becoming increasingly important to petroleum and chemical engineering. The Venturi meter is a favored device for the metering of the unprocessed wet natural gas production flows. When Venturi meters are used in wet gas, the measured differential pressure is higher than it would be in gas phases flowing alone. This phenomenon is called over reading. Eight famous over‐reading correlations have been studied by many researchers under low‐ and high‐pressure conditions, the conclusion is separate flow model and homogeneous flow model performing well both under high and low pressure. In this study, a new metering method is presented based on homogeneous and separate flow theory; the acceleration pressure drop and the friction pressure drop of Venturi under two‐phase flow conditions are considered in new correlation, and its validity is verified through experiment. For low pressure, a new test program has been implemented in Tianjin University′s low‐pressure wet gas loop. Three 50 mm Venturi meters with β values of 0.4048, 0.55, and 0.70 have been tested at the working operation pressure of 0.15, 0.20, and 0.25 MPa, the gas densimetric Froude number from 0.6 to 2.5, the modified Lockhart‐Martinelli parameter from 0.0022 to 0.3, and the ratio of the gas liquid mass flow rate from 0.5 to 0.99. For high pressure, the National Engineering Laboratory offered their reports on the web and their test range with β values of 0.4, 0.60, and 0.75, pressure of 1.5, 3.0, and 6.0 Mpa, gas Froude number from 0.5 to 5.5, and the modified Lockhart‐Martinelli parameter from 0.0035 to 0.3. The coefficients of the new proposed correlation are fitted with all independent data both under high and low pressure. Finally, the applicability and errors of new correlation are analyzed.