An Experimental Investigation of the Air-Side Convective Heat Transfer Coefficient on Wire and Tube Refrigerator Condenser Coils

Hoke, J.L.; Swofford, T.D.; Clausing, A.M.

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https://hdl.handle.net/2142/11122 Copy

Description

Title

An Experimental Investigation of the Air-Side Convective Heat Transfer Coefficient on Wire and Tube Refrigerator Condenser Coils

Author(s)

• Hoke, J.L.
• Swofford, T.D.
• Clausing, A.M.

Issue Date

1995-10

Keyword(s)

convective heat transfer

Abstract

"This thesis presents the results of an experimental investigation of the convective airside heat transfer from wire and tube condensers. The ftrst law of thermodynamics is applied to the ""refrigerant"", water in this investigation, flowing through the tubes in order to determine the total heat loss from the condenser. The test section is 910 mm (36 in) wide by 300 mm (12 in) tall; thus the coil is tested in an essentially inftnite stream. During the course of the experiments, the influence of the free stream air velocity ranging from 0.15 rn/s to 2.0 rn/s (0.49 ftls to 6.56 ftls) is established. The angle of attack, n, was varied from - 40 degrees to 40 degrees with the air flow always normal to the tubes ('11= 1t/2) and varied from -20 degrees to 20 degrees with the air flow normal to the wires ('II = 0). A method for , calculating view factors and the radiation heat transfer for wire and tube condensers is derived. The effect of the length of the coil is measered at 0 and -5°angle of attack. In addition, the influence of the ftn efftciency on the heat transfer is investigated and accounted for in the deftnition of the heat transfer coefftcient. The heat transfer data in the inertia dominated regime (Richardson number less than 0.0013) are correlated assuming NUcoil = t(Re, n, 'II)' g( S: ) with the Reynolds number based on the wire diameter. The range of Reynolds numbers covered is 15.7 < Rew < 207.5. The ranges of coil geometric parameters (nondimensionlized by dividing by the wire diameter) covered in this study are: 3.022 < nondimensional tube diameter < 5.134, 18.84 < nondimensional tube spacing < 40.94,2.819 < nondimensional wire spacing < 4.427,53.80 < nondimensional tube length< 143.6, and 207.2 < nondimensional wire length < 500.2. The function is represented by tl(a)·Reh (a) for 'II = 0 and h(a).Rei4 (a) for'll=1t/2. Approximately 1700 tests were performed in this investigation using seven different coils. The ftnal correlation is capable of predicting the data with 2cr equal to 16.7% for Ri < 0.0013. A limited natural convection study is also presented."

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-86

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/11122

Sponsor(s)/Grant Number(s)

Air Conditioning and Refrigeration Center Project 42

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