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

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

Permalink

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

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

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

Language

en

Permalink

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

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Project 101

Owning Collections