Julie Frank

Background: I graduated from the University of Leeds with a BEng in Mechanical Engineering in which I had three modules directly related to Fluid Dynamics spread over the whole degree. During this degree I was first introduced to research through a year-long individual research project on a hydrogen-based heating system using a CHP-unit.  

Research Interests: I am widely interested in transportation methods and how to improve their efficiency using Fluid Dynamics. 

Why I chose the CDT in Fluid Dynamics: As the Fluid Dynamics related modules during my first degree were the ones I preferred and found the most interesting, I wanted to continue to study something linked to this. The CDT was particularly tempting as the program linked interdisciplinary research and learning, and the possibility to work directly with industry.

Research Summary:
My PhD project focuses on understanding the melting and solidification of Phase Change Materials (PCM) in novel heat exchanger designs for the use in aircraft thermal management systems (TMS). The heat load in aircraft has significantly increased in the previous decades leading to challenges in the design of the TMS. PCM have been identified as a possible solution to this problem as the PCM is capable of absorbing and releasing a large amount of heat at an almost constant temperature during the phase change.

PCM have mostly been used in civil engineering for the insulation of building or in the use of heating, air conditioning and ventilation (HVAC) units. The design of these units has been focused on limiting the pumping power required to operate the heat exchanger, such that the operating costs can be reduced. This has resulted in large and heavy units which are not adapted for the use in aerospace applications. In aircraft, a much shorter phase change cycle is also required as the HVAC units are traditionally designed such that the phase change occurs over the course of multiple hours. This could be achieved by increasing the heat transfer rate by having a much larger surface area between the fluid and the PCM.

As part of this project a numerical framework for modelling the performance of different PCM Heat Exchanger designs is developed. This will be used to evaluate more compact heat exchanger incorporating the PCM which would be adapted for the use in aircraft TMS, as well as identifying improvements in the design and the operating conditions of the heat exchanger.