Understanding two-phase flows and the boiling phenomenon is a major challenge for the CEA, for both the design and safety of nuclear power plants. In a Pressurized Water Reactor (PWR), the heat generated by the nuclear fuel is transferred to the water in the primary circuit. Under accident conditions, the water in the primary circuit can enter a nucleate boiling regime, or even evolve to a boiling crisis. While the phenomenon of boiling is the subject of numerous studies, the dynamics of the generated bubbles also receive special attention at the CEA. This thesis will focus on the coupling between the turbulence generated by a shear flow and the agitation induced by the bubbles. Its originality lies in the study of the effect of gravity, achieved by tilting the channel, a parameter that can generate complex flow regimes.
This experimental work will be based on the new CARIBE facility at CEA Saclay. The PhD student's mission will be to characterize the different flow regimes and then to conduct a detailed study of the flow by implementing specific metrology (including Particle Image Velocimetry (PIV), hot-film anemometry, and optical probes). Conducted within the LE2H laboratory, the project will benefit from a close collaboration with the LDEL (CEA Saclay) and the IMFT (Toulouse). The PhD student will work in a dynamic environment with other PhD students and will present their work at national and international conferences.
We are looking for a candidate with a background in fluid mechanics and a strong interest in experimental work (a Master's thesis internship is possible). This PhD offers the opportunity to develop expertise in instrumentation, data analysis, and turbulent two-phase flows—skills that are highly valued in the energy, industrial, and academic research sectors.