Pressure drop characterization on cryogenic multiphase flow in spiral wounded heat exchanger under high mass flow conditions

Abstract

In order to clarify the influence of dryness, working medium and mass flow rate on pressure drop characteristics in shell side of spiral wound heat exchanger, a simplified test section has been analyzed in this study. The model is with a coiled section under compact design: 1 mm layer spacing of and 2 mm tube spacing in the main structure. The mixed alkane composed of methane, ethane, propane and others are used as working fluid. The current study is focused on the pressure drop behaviors and the effects of multiphase flow in different stages of cooling process in the cryogenic heat exchanger. Systematic numerical model has been established in this study to investigate the pressure behaviors, which are also verified against newly constructed experimental system. Operating conditions range from vapor quality of 0.1–0.9, mass flux of 60–120 kg·(m2·s)−1, under the operation pressure of 0.25 MPa and temperature from −27 °C to −170.6 °C. The absolute error of pressure measurement is less than 1.5 kPa and the absolute error of pressure drop measurement is less than 25 Pa, and the relative error is 0.25 % for the current test. The experimental results show that the friction pressure drop increases with the increase of vapor quality from 0.1 to 0.9 and mass flux from 60 to 120 kg·(m2·s)−1, and the growth gradient of friction pressure drop decreases with the increase of vapor quality. A set of pressure drop correlation has been established to reflect the influence of factors such as vapor quality and mass flow rate, and the deviation between predicted pressure drop and experimental data was within ±20 %.