Development of Generator Tube in an Absorption Chiller-Heater

1996 Fiscal Year Final Research Report Summary

• Project/Area Number: 07650910
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 化学工学一般
• Research Institution: Kagoshima National College of Technology
• Principal Investigator: ESAKI Syuji Kagoshima Nat. Col. Tech., Mech. Eng. Professor., 機械工学科, 教授 (40185111)
• Co-Investigator(Kenkyū-buntansha): TAKANASHI Hiroyuki Kobe Steel Ltd. Researcher, 秦野工場・空調材研究室, 研究員 ; NAKASHIMA Masahiro Mech. Eng. Kagoshima National College of Technology Professor., 機械工学科, 教授 (70124170) ; MISUMI Toshiyuki Mech. Eng. Kagoshima National College of Technology Associate Professor., 機械工学科, 助教授 (20157481)
• Project Period (FY): 1995 – 1996
• Keywords: Heat Transfer / Extended Heat Transfer Surface / Forced Convection / Pressure Loss / Fin / Heat Exchanger

Research Abstract

An experimental study has been performed to clarify the inner heat transfer performance and pressure drop of the generator tubes in an absorption chiller-heater. Test tubes employed were the plain the and the various types of tubes with lots of libs on the inner surface to improve the forced convetion heat tranfer, i.e.number of lib N=10,20,30, lead angle rheta=25,34,43 degree and height of lib h=0.21,0.35,0.54mm. As the result, the pressure drop in the tubes with inner libs increases with increasing the number of lib, the lead angle and the height of lib, and is more than 1.4-2.1 times that in the plain tube. However, the heat transfer performance of the tubes with inner libs is more than 1.3-1.9 times that in the plain tube at the general design velocity 2m/s. Also, it is shown that the tube with inner lib of N=20, rheta=34 degree and h=0.35mm is the most suitable tube from the standpoint of heat transfer performance under the condition of the same pressure gradient.