Study of Flow Characteristics of Gas-Liquid Two-Phase Flow in Plate-Fin Heat Exchanger with Offset Fin

Abstract

This study deals with water single-phase flow and air-water two-phase flow characteristics in plate fin heat exchangers with offset fin. Single channel test sections simulating plate-fin heat exchanger were made by transparent acrylic resin. The length and width of the channel were 435 mm and 90 mm, respectively. Two kinds of offset fins with the fin pitch of 3.2 mm and 2.0 mm were used. Pressure loss characteristics and flow behaviors in the vertical channel test sections were experimentally examined. It was confirmed from the experimental results that the friction factor of water single-phase flows could be correlated by a modified Hagen-Poiseuill equation. In the air-water two-phase flow experiment, two-phase multipliers were larger than the calculation results by a conventional equation in the area of χ > 1 due to flow pulsation and maldistribution. The tendency was larger for the channel with larger fin pitch. Two-phase multipliers for each flow direction in each test section could be correlated by a modified Tribbe-Müller-Steinhagen equation.