Application of Turbine Flow Meter System for Two-phase, Air-Water, Downward Flow in Tube

J. Ocean Eng. Technol. 1998;12(4):70-75.

W. Jaewoo Shim;

하강류의 이상, 공기-물, 유동에서 터빈 유량계 시스템의 응용

심재우;

단국대학교 화학공학과;

Keywords: Two-phase flow, Air-water flow, Turvine flow meter, Volumetric rate,

핵심용어: 이상 유동, 물-공기 유동, 터빈 유량계, 체적 유량

Abstract

An air-water mixture in downflow was passed through two turbine flow meters in series with an intervening valve to provide an adjustable pressure difference between them. The output signals were found to depend only on the actual volumetric flow rate of the gas, Qg, and liquid. Ql, at the flow meter location. Void fractions were measured by two gamma densitometers, one upstream of the flow meters and the other downstream. Below a critical water flow rate, the void fractions exhibited nearly discontinuous increases with increasing gas flow, as well as hysteresis loops, yet the turbine flow meter showed no unusual behavior. Consequently, the models of Popper (961) and Aya (1975), which depend on void fraction, yielded very poor predictions for downflow. A modification of Popper equation, based on the nominal volume fraction, Qg/(Qg+Ql), showed that volume fraction has closer functional relation than with void fraction.