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Title: Distribution of air-water mixtures in parallel vertical channels as an effect of the header geometry

Uneven phase distribution in heat exchangers is a cause of severe reductions in thermal performances of refrigeration equipment. To date, no general design rules are available to avoid phase separation in manifolds with several outlet channels, and even predicting the phase and mass distribution in parallel channels is a demanding task. In the present paper, measurements of two-phase air-water distributions are reported with reference to a horizontal header supplying 16 vertical upward channels. The effects of the operating conditions, the header geometry and the inlet port nozzle were investigated in the ranges of liquid and gas superficial velocities of 0.2-1.2 and 1.5-16.5 m/s, respectively. Among the fitting devices used, the insertion of a co-axial, multi-hole distributor inside the header confirmed the possibility of greatly improving the liquid and gas flow distribution by the proper selection of position, diameter and number of the flow openings between the supplying distributor and the system of parallel channels connected to the header. (author)
Authors:
; ;  [1]
  1. Diptem, University of Genova, Via all'Opera Pia 15a, 16145 Genova (Italy)
Publication Date:
OSTI Identifier:
21195816
Resource Type:
Journal Article
Resource Relation:
Journal Name: Experimental Thermal and Fluid Science; Journal Volume: 33; Journal Issue: 5; Other Information: Elsevier Ltd. All rights reserved
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; 32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATION; MASS DISTRIBUTION; AIR; CONFIGURATION; MIXTURES; WATER; HEAT EXCHANGERS; GAS FLOW; REFRIGERATING MACHINERY; DESIGN; LIQUID FLOW; OPENINGS; PERFORMANCE; PLATES; VELOCITY; THERMAL EFFICIENCY; TWO-PHASE FLOW Flow distribution; Air-water mixture; Parallel channels; Plate heat exchangers; Flute fitting