Single phase pressure drop and two-phase distribution in an offset strip fin compact heat exchanger

Abstract

Experiments have been conducted in a compact heat exchanger with two-phase inlet conditions and vertical upflow in order to study the flow behavior. The test section consists of an offset strip fin heat exchanger with a rectangular cross-section (dimensions: 1 m × 1 m × 7.13 mm). The distributor was designed to optimize two-phase flow distribution. In a preliminary step, pressure drop of single phase flow in offset strip fins is needed to assess the quality of the distribution in the single phase case. For that, pressure drop of single phase flow has been measured in the experimental loop. Pressure drop has also been analysed numerically via CFD simulations. For low Reynolds numbers, numerical results show good agreement with experimental measurements. In a second step, the two-phase flow distribution at the outlet was characterized using air and water as working fluids and for different operating conditions. This characterization consists of the measurement of gas and liquid flow rates in different zones evenly distributed at the outlet. We observed that high air flow rates led to a more homogenous distribution.