Theoretical and experimental study of the heat transfer characteristics of spiral-coil heat exchangers

การศึกษาเชิงทฤษฎีและเชิงทดลองเกี่ยวกับคุณลักษณะการถ่ายเทความร้อนของอุปกรณ์แลกเปลี่ยนความร้อนแบบท่อขดเป็นวง

Name: Paisarn Naphon

Organization : King Mongkut's University of Technology Thonburi. Faculty of Engineering. Mechanical Engineering

keyword: การถ่ายเทความร้อน

; Heat transmission

; Heat exchangers

Abstract: The heat transfer characteristics and thermal performance of the spiral-coil heatexchangers are studied experimentally and theoretically. The experimental setup isdesigned and constructed. The test loop consists of a test section, refrigerant loop,chilled water loop, hot air loop and data acquisition system. The water and air are usedas working fluids. The test sections are the spirally coiled tube heat exchanger and thespirally coiled finned tube heat exchangers consist of the shell and spiral coil unit. Theheat exchangers consist of six layers of concentric spirally coiled tube. Each tube isconstructed by bending straight copper tube into a spiral-coil. The mathematical modelsused to describe the heat transfer characteristics are developed from the conservationequations of energy and mass. The experiment consists of two steps. The first one is todetermine the tube-side and air-side heat transfer coefficients and the second one is toobtain the data for verifying the simulation results.The results obtained from the experiments showed that the tube-side and air-side heattransfer coefficients obtained from experiments are fitted into the forms of thecorrelations. The tube-side heat transfer coefficients under dry-and wet-surfaceconditions are presented in term of the Nusselt numbers, while air-side heat transfercoefficients are presented in term of the Colburn J factors. For spirally coiled tube heatexchanger, the Nusselt numbers obtained fiom the correlations under dry-and wetsurfaceconditions are correlated to fall within f 20 percent and 10f percent,respectively, while the Colburn J factors for dry-and wet-surface obtained from thecorrelations are correlated to fall within f 15 percent and f 15 percent, respectively.For spirally coiled finned tube heat exchanger, the Nusselt numbers obtained from thecorrelations under dry-and wet-surface conditions are reasonable agreement with theexperimental data with average errors f 15 percent and 15 f percent, respectively,while the Colburn J factors with average errors + 12.5 percent and + 12.5 percent,respectively.The heat transfer characteristics and the relevant parameters of the spiral-coil heatexchangers, far example the enthalpy effectiveness and humidity effectiveness, theoutlet- water and-air temperatures, the outlet-air humidity ratio and the heat transfer rateobtained from the models are validated by comparison with the measured resultsobtained from the experiments. The results obtained from the models show reasonableagreement with the experimental data.

King Mongkut's University Technology Thonburi. Library

Address: Bangkok

Email: info.lib@mail.kmutt.ac.th

Name: Somchai Wongwises

Role: Advisor

Created: 2004

Issued: 2007-07-20

Modified: 2014-05-26

วิทยานิพนธ์/Thesis

ISBN: 9741839022

CallNumber: MEE1580

eng

DegreeName: Doctor of Engineering

Level: Doctoral Degree

Descipline: Mechanical Engineering

Grantor: King Mongkut's University of Technology Thonburi

©copyrights King Mongkut's University of Technology Thonburi

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