Mass Transfer in Two-Phase Gas-Liquid Flow in a Tube and in Channels of Complex Configuration

Abstract

Successive and versatile investigation of heat and mass transfer in two-phase flows is caused by their wide application in power engineering, cryogenics, chemical engineering, and aerospace industry, etc. Development of new technologies, upgrading of the methods for combined transport of oil and gas, and improvement of operation efficiency and reliability of conventional and new apparatuses for heat and electricity production require new quantitative information about the processes of heat and mass transfer in these systems. At the same time necessity for the theory or universal prediction methods for heat and mass transfer in the two-phase systems is obvious. In some cases the methods based on analogy between heat and mass transfer and momentum transfer are used to describe the mechanism of heat and mass transfer. These studies were initiated by Kutateladze, Kruzhilin, Labuntsov, Styrikovich, Hewitt, Butterworth, Dukler, et al. However, there are no direct experimental evidences in literature that analogy between heat and mass transfer and momentum transfer in two-phase flows exists. The main problem in the development of this approach is the complexity of direct measurement of the wall shear stress for most flows in two-phase system. The success of the analogy for heat and momentum transfer was achieved in the prediction of heat transfer in annular gas-liquid flow, when the wall shear stress is close to the shear stress at the interface between gas core and liquid film. Following investigation of possible application of analogy between heat and mass transfer and hydraulic resistance for calculations in two-phase flows is interesting from the points of science and practice. The current study deals with experimental investigation of mass transfer and wall shear stress, and their interaction at the cocurrent gas-liquid flow in a vertical tube, in channel with flow turn, and in channel with abrupt expansion. Simultaneous measurements of mass transfer and friction factor on a wall of the channels under the same flow conditions allowed us to determine that connection between mass transfer and friction factor on a wall in the two-phase flow is similar to interconnection of these characteristics in a single-phase turbulent flow, and it can be expressed via the same correlations as for the single-phase flow. At that, to predict the mass transfer coefficients in the two-phase flow, it is necessary to know the real value of the wall shear stress. www.intechopen.com Mass Transfer in Multiphase Systems and its Applications 156 2. Analogy for mass transfer and wall shear stress in two-phase flow 2.1 Introduction The combined flow of gas and liquid intensifies significantly the heat and mass transfer processes on the walls of tubes and different channels and increases pressure drop in comparison with the separate flow of liquid and gas phases. According to data presented in (Kutateladze, 1979; Hewitt & Hall-Taylor, 1970; Collier, 1972; Butterworth & Hewitt, 1977; et al), the methods based on semi-empirical turbulence models a...

Mass Transfer in Single Bends Under Annular Two Phase Flow Conditions

“…The enhancement in the mass transfer rate at the inlet is likely due to the acceleration of the flow on the inner wall. The acceleration as the flow enters the bend is due to the reduced pressure near the wall to keep the flow from separating, similar to what is seen at lower distribution for (a) Jv=30.2mls, JL = 0.^7, 0.28, and 0.41 m/s and (b) JL = 0.28 m/s, J^ = 22, 24.5, and 29.5 m/s void fractions [12]. Here, though, it only occurs in the film rather than across the full flow.…”

“…Investigations of two phase flow in pipe bends have focused on evaluating the pressure drop along the bend curvature [4][5][6], visualization of the flow [7][8][9], and characterizing the heat and mass transfer in the bend [10][11][12]. The phase redistribution in long radius bends for high void fraction annular flows revealed distributions of the two phases that could be related to the interaction between gravity, centripetal, and inertial forces [7][8][9].…”