!!! URGENT : Postdoctoral Fellowship in Advanced Droplet Impact and Phase Change Studies

The “Transfers in Fluids” research team is concerned with heat and mass transfers between flowing liquid droplets (and even more generally, a flowing liquid), a gas and/or a solid wall, addressing couplings between hydrodynamics, transfer phenomena and phase changes (evaporation, solidification). The team's activities are spearheaded by a multi-scale experimental approach in support of modeling. In particular, the development of innovative non-intrusive optical diagnostics applied to droplets and sprays continues to be a flagship activity of the group, recognized internationally: droplet temperature measurement ((planar) laser-induced fluorescence, LIF/(P)LIF with two colors or two dyes), granulometry/temperature coupling (LIF-PDA) or granulometry/fluxmetry/wall thermometry (PDA-Infrared thermography), high-speed quantitative shadowgraphy (size/speed correlations).

We are looking for a candidate for a post-doctoral position in a fluid mechanics and energy laboratory in Nancy ( Grand-Est, France). The project concerns the characterization of heat and mass transfer during the impact of droplets on a heated wall in the context of spray cooling. The candidate will carry out mainly experimental work using coupled techniques, i.e. infra-red thermography to estimate the heat flux extracted from the wall, and shadowgraphy imaging to observe the spreading dynamics of the droplets on the wall. The aim is to highlight the role of wall properties in boiling regimes, where wall wettability and/or texturing will play a major role. 

The candidate will work in close collaboration with PhD students and trainees to propose the most suitable surfaces for intensifying transfers according to the specifications. 

This position is for 12 months, with a start no later than 20th May 2025. The salary is based on experience and follows national academic rates for postdoctoral researchers. We will support candidates in applying for national and international postdoctoral fellowships. Our lab offers an international and highly collaborative research environment, access to cutting-edge facilities including advanced imaging systems and instruments. The lab is engaged in national and international collaborations and institutional programs, providing access to textured surfaces that show great promise for the targeted applications

We are seeking a candidate with a Ph.D. in fluid mechanics, thermal sciences, or a related field. The ideal candidate should be passionate about experimental approaches and collaborate closely with our team to study the impact of droplets on surfaces under non-isothermal conditions. A proven track record in any of these areas is highly valued.

Droplets play a crucial role in numerous natural processes and technological applications, from atmospheric phenomena like rain clouds to industrial processes such as spray cooling of electronics. Due to their ubiquitous presence, droplets have long been a subject of scientific inquiry. When a droplet impacts a solid surface, it can exhibit a variety of behaviors, including deposition, bouncing, or splashing, driven by the complex interaction of liquid inertia, viscosity, surface tension, and the properties of the solid substrate.

Despite extensive research on these phenomena, significant knowledge gaps remain, particularly when impact conditions are non-isothermal, especially at high temperatures. Under such conditions, boiling can manifest in several forms (such as bubbling, thermal spraying, or the formation of a vapor f ilm beneath the droplet), which can significantly alter the spreading and residence time of the droplet, as well as the rate of heat transfer.

The postdoctoral researcher will contribute to several national projects, including an ANR project focused on the spray cooling of textured surfaces. The objective is to leverage and develop innovative experimental methods, such as infrared (IR) thermography, to obtain quantitative data on heat and mass transfer processes. Various types of surfaces will be compared, particularly those that modify wettability and nucleation site density, in experiments conducted at both the individual droplet scale and the spray scale.