University of Illinois Urbana-Champaign

Friction and Heat Transfer Characteristics for Single-Phase Flow in Microchannel Condenser Tubes

Graham, T.P.

Content Files
TR078.pdf

Permalink

https://hdl.handle.net/2142/11027

Description

Title
Friction and Heat Transfer Characteristics for Single-Phase Flow in Microchannel Condenser Tubes
Author(s)
Graham, T.P.
Contributor(s)
Dunn, W.E.
Issue Date
1995-06
Keyword(s)
microchannel condenser tubes
Date of Ingest
2009-04-17T19:11:54Z
Abstract
An experimental study of friction and heat transfer characteristics for single-phase flow in microchannel condenser tubes was conducted. Data were collected for the adiabatic flow of nitrogen, and also for the diabatic flow of single-phase R134a w.ith air in cross-flow. The nitrogen data were analyzed to obtain friction factors in the Reynolds number range of 500-20000, and the R134a data were analyzed to obtain Nusselt numbers in the Reynolds number ranges of 1000-7000 and 10000-70000. Several types of microchannel tubes were considered, including those with circular, square, enhanced square, and equilateral triangular ports. For each tube geometry, friction factors in the laminar regime follow the known analytical solution, but the critical Reynolds numbers for the noncircular tubes are all smaller than the value of 2100 found for the circular-port tube. In the turbulent regime, microchannel tube friction. factors follow a correlation for smooth tubes given by Churchill. Accordingly, there is no evidence of surface roughness or small length scale effects. Finally, Nusselt numbers in the range of 10000-70000, obtained from superheated vapor data, are within 10% of the correlation given by Gnielinski. The heat transfer data in the range of 1000-7000, obtained from subcooled liquid, are inconclusive.
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-78
Type of Resource
text
Genre of Resource
Technical Report
Language
en
Permalink
http://hdl.handle.net/2142/11027
Sponsor(s)/Grant Number(s)
Air Conditioning and Refrigeration Center Project 48

Owning Collections

Technical Reports - Air Conditioning and Refrigeration Center PRIMARY