University of Illinois Urbana-Champaign

Critical Heat Flux of CO2 in a Microchannel at Elevated Subcritical Pressures

Aldana, J.P.; Georgiadis, J.G.; Jacobi, A.M.

Content Files
TR195.pdf

Permalink

https://hdl.handle.net/2142/12048

Description

Title
Critical Heat Flux of CO2 in a Microchannel at Elevated Subcritical Pressures
Author(s)
  • Aldana, J.P.
  • Georgiadis, J.G.
  • Jacobi, A.M.
Issue Date
2002-03
Keyword(s)
  • in-tube heat transfer
  • heat transfer
  • transcritical CO2
Date of Ingest
2009-06-04T21:52:10Z
Abstract
The connection between chlorofluorocarbons and ozone depletion has prompted a resurgence in the study of environmentally friendly refrigerants for heat exchanger applications. Recent studies have shown compact heat exchangers using a transcritical CO2 cycle optimized in a microchannel geometry are competitive with baseline units in terms of physical dimension and thermal performance. However, the critical heat flux may occur at lower-than-expected vapor qualities in the heat absorption portion of the cycle, significantly affecting heat exchanger performance. The purpose of this study is to determine the critical heat flux and associated vapor quality under conditions simulating compact heat exchanger conditions. Non-intrusive wall temperature measurements, in conjunction with standard transducer measurements and flow visualization, were used to detect critical heat flux phenomenon. The vapor qualities associated with the critical heat flux were determined to be lower than would be expected in larger-diameter channels, and the critical heat flux was lower than predicted by the Shah correlation.
Publisher
Air Conditioning and Refrigeration Center. College of Engineering. University of Illinois at Urbana-Champaign.
Series/Report Name or Number
Air Conditioning and Refrigeration Center TR-195
Type of Resource
text
Genre of Resource
Technical Report
Language
en
Permalink
http://hdl.handle.net/2142/12048
Sponsor(s)/Grant Number(s)
Air Conditioning and Refrigeration Project 101

Owning Collections

Technical Reports - Air Conditioning and Refrigeration Center PRIMARY