An Experimental Investigation of Pressure Drop and Heat Transfer in Internally Enhanced Aluminum Microchannels

Monroe, C.A.; Newell, T.A.; Chato, J.C.

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https://hdl.handle.net/2142/12167 Copy

Description

Title

An Experimental Investigation of Pressure Drop and Heat Transfer in Internally Enhanced Aluminum Microchannels

Author(s)

• Monroe, C.A.
• Newell, T.A.
• Chato, J.C.

Issue Date

2003-04

Keyword(s)

• microchannel heat exchangers
• heat exchangers
• flat plate heat exchangers

Abstract

Pressure drop and heat transfer measurements were taken for smooth and internally enhanced aluminum microchannels using pure R134a. Adiabatic, evaporation, and condensation tests were conducted in the horizontally-oriented test sections. Hydraulic diameters for the real dimensions of the two test sections measured 1.66 and 0.76 mm (0.065” and 0.030”), respectively. The test conditions included mass fluxes from 50 to 430 kg/m2s (37—317 klbm/ft2hr), inlet qualities of 0 to 100%, and test section heat fluxes from 2.3 to 8.0 kW/m2 (730 to 2540 Btu/ft2hr). All two-phase experiments were run at an inlet temperature of 5°C (41°F). Experimental data showed an average increase of a factor of two in pressure drop for the enhanced test section, but with diminishing effects at higher mass fluxes and qualities. Heat transfer data showed an increased heat transfer coefficient in the enhanced test section, with average increases of a factor of two over the basic test section. When coupled with the area enhancement, the enhanced test section gave almost four times the heat transfer capacity of the basic test section. Condensation experiments were also conducted to try to isolate nucleate boiling effects in evaporation. Numerical simulations were constructed to help illustrate the differences between the two test sections and their potential applications. Results from these experiments are presented in this thesis. In addition, the data is compared to pressure drop and heat transfer correlations to help explain the characteristics of the two test sections.

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-213

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/12167

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Project 135

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