Numerical, Analytical, and Experimental Studies of Reciprocating Mechanism Driven Heat Loops for High Heat Flux Cooling

Authors

Olubunmi Tolulope Popoola, Florida International UniversityFollow

Document Type

Thesis

Degree

Doctor of Philosophy (PhD)

Major/Program

Mechanical Engineering

First Advisor's Name

Yiding Cao

First Advisor's Committee Title

Committee Chair

Second Advisor's Name

George Dulikravich

Second Advisor's Committee Title

committee member

Third Advisor's Name

Cheng-Xian Lin

Third Advisor's Committee Title

committee member

Fourth Advisor's Name

Walter Tang

Fourth Advisor's Committee Title

committee member

Fifth Advisor's Name

Ibrahim Nur Tansel

Fifth Advisor's Committee Title

committee member

Keywords

Reciprocating Flow, cooling, two Phase, Nusselt number correlation, heat loop, reciprocating mechanism driven heat loop

Date of Defense

11-14-2017

Abstract

The Reciprocating Mechanism Driven Heat Loop (RMDHL) is a novel heat transfer device that utilizes reciprocating flow, either single-phase or two-phase flow, to enhance the thermal management in high tech inventions. The device attains a high heat transfer rate through a reciprocating flow of the working fluid inside the heat transfer device. Although the concept of the device has been tested and validated experimentally, analytical or numerical studies have not been undertaken to understand its working mechanism and provide guidance for the device design. The objectives of this study are to understand the underlying physical mechanisms of heat transfer in internal reciprocating flow, formulate corresponding heat transfer correlations, conduct an experimental study for the heat transfer coefficient, and numerically model the single-phase and two-phase operations of the RMDHL to predict its performance under different working conditions. The two-phase flow boiling model was developed from the Rensselaer Polytechnic Institute (RPI) model, and a virtual loop written in C programming language was used to eliminate the need for fluid structure interaction (FSI) modelling. The accuracy of several turbulence formulations, including the Standard, RNG, and Realizable k-ɛ Models, Standard and SST k-ω Models, Transition k - - ω Model, and Transition SST Model, have been tested in conjunction with a CFD solver to select the most suitable turbulence modelling techniques. The numerical results obtained from the single-phase and two-phase models are compared with relevant experimental data with good agreement. Three-dimensional numerical results indicate that the RMDHL can meaningfully reduce the peak temperature of an electronic device and result in significantly more uniform temperature across the device. In addition to the numerical study, experimental studies in conjunction with analytical studies are undertaken. Experimental data and related heat transfer coefficient as well as practically useful semi-empirical correlations have been produced, all of which provide archival information for the design of heat transfer devices involving a reciprocating flow. In particular, this research will lead to the development of more powerful RMDHLs, achieve a heat flux goal of 600 W/cm², and significantly advance the thermal management at various levels. Considering the other advantages of coolant leakage free and the absence of cavitation problems, the RMDHL could also be employed for aerospace and battery cooling applications.

Identifier

FIDC004065

Recommended Citation

Popoola, Olubunmi Tolulope, "Numerical, Analytical, and Experimental Studies of Reciprocating Mechanism Driven Heat Loops for High Heat Flux Cooling" (2017). FIU Electronic Theses and Dissertations. 3505.
https://digitalcommons.fiu.edu/etd/3505