Safe Use of Flammable Refrigerants: Evaluating Refrigerant Leakage Flow Rate in Small Heat Pumps
This research aims to develop a model for calculating the transient leakage flow rate of refrigerants in refrigeration systems, focusing on characterizing the flammability risks associated with hydrocarbon (HC) and other flammable refrigerants. The study will address scenarios involving unintentional leakage through defined holes.
Background
The safe application of flammable refrigerants is a growing concern within the refrigeration, air conditioning, and heat pump industry. These refrigerants, although potentially flammable under specific conditions, are increasingly favored due to their environmentally friendly properties compared to non-flammable alternatives.
Existing methods often estimate leakage flow rates using steady-flow equations for orifice discharge under sub-critical or choked flow conditions. However, refrigeration systems have unique characteristics that require additional considerations:
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The finite refrigerant mass within the system.
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Phase transition from two-phase to single (vapor) phase discharge.
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The influence of internal evaporation on upstream pressure reduction.
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The operational effect of a working compressor.
Task Description
The primary objective of this thesis is to develop a method to calculate the transient leakage rate after an unintentional refrigerant release. The work will include:
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Conducting a comprehensive literature review on heat pump systems and leakage fundamentals to establish a solid understanding of the topic.
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Developing an analytical or numerical method, based on the findings from the literature review, to estimate transient refrigerant leak rates.
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Validating the proposed method against existing experimental data and providing a thorough justification for the results.
Learning Outcomes
The student will:
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Gain expertise in fluid dynamics, mass transfer, and natural refrigerants, which is area of significant interest in modern refrigeration technology.
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Have the opportunity to co-author a conference or even journal article based on the results of this project, in collaboration with the research team.
Prerequisites
A fundamental understanding of thermodynamics, mass transfer, and computational fluid dynamics.
Timeline
The thesis is expected to start in January 2025 and with a duration of up to 6 months.
How to Apply
Interested candidates should send their CV to Jafar Esmaeelian .
Supervisor
Examiner
