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Indexed by:期刊论文

Date of Publication:2018-05-01

Journal:INTERNATIONAL COMMUNICATIONS IN HEAT AND MASS TRANSFER

Included Journals:SCIE

Volume:94

Page Number:1-13

ISSN No.:0735-1933

Key Words:Ionic liquids; Oscillating heat pipe (OHP); Startup; Pulsation characteristics; Thermal performance

Abstract:This paper attempted to investigate the effects of ionic liquids (ILs) addition on the startup, operation and thermal performance of a closed loop copper oscillating heat pipe (OHP, four turns). The liquid slug oscillation characteristics and flow pattern of the OHP with various heat input were also experimentally examined utilizing high-speed camera. The experimental results showed that for higher ILs mass fractions, the OHP behaved a lower startup power (decrease of 29 W) and startup temperature (decrease of 11 C), which are favorable of not only facilitating a faster startup of the OHP but also effectively avoiding the "dry-out" problem. When the mass fraction of ILs was 0.67%, the ILs-water based OHP substantially had the same amplitude and the velocity as water-based OHP. When the ILs addition was respectively 19.1% and 44.4% (mass fraction), the oscillation liquid slug displayed a high frequency and small amplitude characteristics. In case of a low mass fraction of ILs, ILs-water based OHP nearly perform the same heat transfer performance as the water based OHP presented. However, the heat transfer performance of the ILs-water based OHP showed a slight decrease of 10% at higher heat input (>220 W), which in general did not affect the overall thermal performance and operational stability of the OHP. A modified correlation of Kutateladze number (Ku) was established and could basically predict the thermal performance within approximately 10% deviation in the vertical closed loop OHP at a filling ratio around 65% considering the effects of ILs addition.