Studies of Mechanically-Pumped Two-Phase Loops Under Pulsed Evaporator Heat Loads
Date of Award
12-12-2024
Degree Name
Ph.D. in Mechanical Engineering
Department
Department of Mechanical and Aerospace Engineering
Advisor/Chair
Jamie Ervin
Abstract
As avionics become more power dense, electronic device cooling has become a significant barrier for aircraft integration. Mechanically pumped two-phase loops (MPTL) are a thermal subsystem with many desirable characteristics to address future aircraft heat loads. This dissertation has three main sections and uses numerical and experimental techniques to develop component technology and provide additional system characterization for MPTL transient operation. In the first section, a compressible volume accumulator is added to a MPTL to assess performance improvements for a single pulsed evaporator heat load. This study demonstrates that incorporation of compressible volume into a MPTL can provide near isothermal evaporator operation whereas a fixed-volume MPTL architecture cannot maintain isothermal requirements. The second study uses a validated numerical model to evaluate performance benefits provided by an advanced controls approach, model predictive control, compared to a traditional, proportional-integral control scheme for a single MPTL architecture. Multiple evaporator heat load profiles were applied using simulation, and the model predictive control scheme demonstrated improved isothermal operation compared to traditional control techniques. The third study evaluates system packaging considerations for MPTL compactness through assessment of large curvature ratio, 180° U-bend test articles. An electrical capacitance measurement device was used to examine hydraulic impacts on two-phase refrigerant flow for multiple two-phase flow patterns and U-bend geometries. Experimental results indicate the U-bend impacts the refrigerant upstream less than downstream and the analysis of x-location center of mass and the L2-norm do not provide sufficient data to support or refute current refrigerant re-development recommendations. In summary, each of these studies offer techniques to improve MPTL transient operation and compactness, which will provide benefit for future aircraft thermal management system integration.
Keywords
Aerospace Engineering, Mechanical Engineering
Rights Statement
Copyright © 2024, author.
Recommended Citation
Truster, Nicholas, "Studies of Mechanically-Pumped Two-Phase Loops Under Pulsed Evaporator Heat Loads" (2024). Graduate Theses and Dissertations. 7489.
https://ecommons.udayton.edu/graduate_theses/7489
