False Transient Evaporator Thermal Model of the 'Closed Loop TwoPhase Wicked Thermosyphon (CLTPWT)' Studying Slug-Plug Liquid Vapor Flow

Karthik S. Remella, Frank M. Gerner
2017 Proceedings of the 3rd World Congress on Mechanical, Chemical, and Material Engineering   unpublished
A novel Closed Loop Two-Phase Wicked Thermosyphon (CLTPWT) was developed, fabricated, and tested by BritePointe Inc., a California based start-up, for providing thermal solutions to high power overhead light emitting diodes (LEDs). This device has structural similarities with loop heat pipes (LHPs), but the driving potential is due to a positive gravitational head (similar to a closed loop thermosyphon). The primary objective of this paper is to present a false-transient thermal model of the
more » ... porator package of this device. The evaporator package houses of two wick structuresa sintered porous wick and a single metallic wire mesh screen (folded to form mini-channels). The sintered porous wick is centrally above the mesh screen channels. The phase change takes place inside these mini-channels and the model assumes a slug-plug two-phase flow leaving the evaporator such that the quality of the two-phase mixture is ~ 0.2. This flow regime is modeled using a time averaged uniform heat transfer coefficient obtained from nucleate flow boiling literature. The substrate temperature predictions are found to be in agreement with experimental tests conducted on the CLTPWT. It is observed that the presence of a central sintered porous wick controls the location of phase change in the mesh screen channels ensuring reliable operation of the device.
doi:10.11159/htff17.148 fatcat:64t2twpyxrc25ns7oplu2ibopa