Analysis and active control of flow instabilities in microchannel cooling systems
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Authors
Jin, Qi
Issue Date
2019-12
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Mechanical engineering
Alternative Title
Abstract
The thesis characterizes the multiphase flow and heat transfer via experiments and computational modeling and conducts a system-level investigation of various factors affecting the overall stability. In both cycles, the pressure drop oscillations occur only under certain combinations of system parameters, which could be predicted using computational modeling. The ability to predict system behavior led to the development of active control strategies that successfully avoid flow instabilities, even in the presence of significant variations in the heat loads. This approach allows maintaining conditions that maximize the efficiency of the two-phase systems. The control methodology was also extended to handle multiple evaporators experiencing asynchronous and unanticipated heat loads. This thesis also analyzes the challenge posed by flow maldistribution accompanying pressure drop oscillation in parallel channels and multi-evaporator systems. The computational model and experiments indicate that the extent of thermal and flow coupling between the parallel channels or evaporators can affect flow maldistribution. The study demonstrates better synchronization in performance when the coupling between the channels or evaporators is improved. Several strategies advanced in this thesis can be readily implemented in several industrial applications, making them more robust and efficient in handling a wide range of operating conditions.
Description
December 2019
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY