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Heat Pipe Science and Technology, An International Journal

ISSN Print: 2151-7975
ISSN Online: 2151-7991

Heat Pipe Science and Technology, An International Journal

DOI: 10.1615/HeatPipeScieTech.2015013430
pages 65-76

EXPERIMENTAL STUDY ON PULSATING HEAT PIPE USING SELF-REWETTING FLUID AS A WORKING FLUID: VISUALIZATION OF THIN LIQUID FILM AND SURFACE WAVE

Koji Fumoto
Department of Intelligent Machines and Engineering, Hirosaki University, 3 Bunkyo-cho Hirosaki, 0368561, Japan
Takuya Ishida
Department of Intelligent Machines and Engineering, Hirosaki University, 3 Bunkyo-cho Hirosaki, 0368561, Japan
Tsuyoshi Kawanami
Department of Mechanical, Engineering, Kobe University, 1-1 Rokkodai-cho, Nada-ku, Kobe, 6578501, Japan
Takao Inamura
Department of Intelligent Machines and Engineering, Hirosaki University, 3 Bunkyo-cho Hirosaki, 0368561, Japan

ABSTRACT

Pulsating heat pipes (PHPs) are a new type of efficient heat transfer for small devices, which were introduced in the mid-1990s by H. Akachi. PHPs can be used to cool electronics by eliminating high heat flux. In this study, flow visualization was conducted for an open-loop PHP using a high-speed camera. The PHP was composed of a glass tube with an internal diameter of 1.8 mm, heated by an electric heater and cooled by water at a constant temperature. The evaporator had 10 rotations and 20 channels. The working fluid employed was comprised of a self-rewetting fluid, water, and ethanol. The self-rewetting fluid was a dilute aqueous solution of alcohols with a large number of carbon atoms (such as butanol and pentanol). These solutions can be considered as self-rewetting fluids because such fluids display nonlinear dependence of the surface tension with temperature. The results indicated that the working fluid characteristics had a strong influence on the performance. When using self-rewetting fluid as the working fluid, the temperature of the adiabatic section was higher than that of the water. Moreover, a peculiar wavy, thin layer of water was observed on the wall of the channel.