Multiphase flows under peri-critical conditions in PhD student's research | Gdańsk University of Technology

Page content


Date added: 2024-07-04

Multiphase flows under peri-critical conditions in PhD student's research

Michał Pysz
Photo: Krzysztof Krzempek/Gdańsk Tech 
Michał Pysz, a graduate of the Doctoral School at Gdańsk University of Technology, undertook a study of multiphase flows under peri-critical conditions for his dissertation. Together with his supervisor, Prof. Dariusz Mikielewicz, he conducted observations of the physical phenomenon associated with flow boiling in very thin channels of 1 to 3 mm in diameter. Such flows are found, for instance, in high-temperature heat pump systems and ORC power stations.

Michał Pysz states the objective of the dissertation was to address an existing literature gap on flow boiling in medium and high reduced pressure regions. To achieve this goal, he designed and built a dedicated test rig to study the transfer and resistance of flows in elevated reduced pressure conditions. As part of his research activities, 1,321 experimental points were collected for boiling flow in the vertical channel of R1233zd(E) and 597 experimental points in the horizontal channel of R1234ze(E).

The PhD student conducted a study to determine the effects of selected thermal-fluid parameters (mass velocity, heat flux, reduced pressure) on heat transfer and flow resistance. Furthermore, he identified the structures of two-phase flows using a dedicated calculating code and described the influence of these structures on heat transfer mechanisms in the case study. The original flow boiling model was modified based on the obtained experimental data. The modifications to the model included the inclusion of the effect of reduced pressure on the part responsible for bubbling boiling. He then compared the updated model with other existing models in literature and tested it on a database consisting of 6,581 experimental points obtained for a number of different factors.

Michał Pysz graduated from the AGH University of Science and Technology in Cracow with a master's degree. He then began his first scientific work at the Polish Academy of Sciences' Institute of Fluid-Flow Machinery in Gdańsk. He then spent four years at the Doctoral School. As a PhD student, he was awarded a scholarship from the French Embassy, which enabled him to conduct research at the University of Lyon for three months.

He is currently planning to go on a 12-month internship at the University of Padova, as part of the Americium program. He is also considering a temporary position in the industry to gain insight into the practical application of research in the business environment.

–I greatly enjoy teaching students and feel that the experience gained on the other side would be highly valuable in my role as a lecturer – the scientist points out. – Currently, I am employed at the Institute of Energy within the Faculty of Mechanical Engineering and Ship Technology, where I am engaged in a number of projects. For instance, our team is currently working on the construction of a mini power station powered by gases obtained from the gasification of sewage waste. We are exploring various ecological alternatives to unconventional power stations, which is an extremely interesting topic. I am excited to face the many scientific challenges ahead of me.