We have developed an experimental set up devoted to perform temperature measurements using fluorescent nano-particles dispersed in a liquid phase. Application to the determination of thermal effects in turbulent cavitating flows have been performed recently (F. Ayela et al., Phys. Rev. E 88, 043016 (2013)). We are looking for a post doctoral researcher, familiar with experiments.His/her role will be to bring useful innovations in an experimental set up devoted to perform local thermal measurement in cavitating micro-flows (design of new micro-systems, use of a confocal microscope). That will be in order to perform combined thermal and velocity measurement with the help of fluorescent nano-particles seeded in the flow. He/she will have to propose physical explanations related to the experimental data. He/she will also involve in X ray instrumentation and void ratio measurements. Some background in LIF, PIV, micromachining and clean room environment will be appreciated.
Description
The project aims to investigate the thermophysical properties of cavitating two-phase flows, with an emphasis to thermal effects associated to viscous heating, liquid – vapor latent heat, and temperature inside a collapsing bubble. Moreover, the knowledge of the average and turbulent velocity distributions, and their correlation with the thermal and density distributions, should be a major advance in fluid mechanics. Because of the poor experimental database for this kind of flow, there is a need of experimental academic studies to validate modeling strategies used in numerical simulation and to investigate the physical phenomena due to the thermodynamic effects during vaporization and condensation in turbulent flows. The project presented here aims to succeed in getting experimental data in an academic configuration such as a turbulent sheared two-phase flows. We will measure simultaneously velocity, density and temperature to describe the coupling phenomena between turbulence and thermodynamics effects of phase change (cavitation) in this kind of turbulent cavitating flows. Furthermore, turbulence and multiphase flows are two of the most challenging topics in fluid mechanics and when combined with thermal effects they pose a great challenge. It is necessary to examine in detail the implications of density and phase variations in turbulence and also to investigate the competing impacts of thermodynamics effects on cavitation. Our approach is based on the use of thermosensitive fluorescent nanoparticles to perform local non-intrusive measurements of the temperature and the velocity fields of the liquid phase. This will be done using a confocal microscope to study flows in microchannels configurations (microdiaphragms and microventuris) displaying turbulent cavitating two phase flows. These micromachined devices will be adapted to X rays-absorption techniques for void ratio measurements and to micro-PIV-LIF in order to obtain instantaneous velocity and temperature fields. Reference : F. Ayela et al., Phys. Rev. E 88, 043016 (2013)
Benefits
salary : 2500 euros / month
Additional Job Details
The postdoctoral fellow will join the LEGI laboratory. His/her role will be to bring useful innovations in an experimental set up devoted to perform local thermal measurement in cavitating micro-flows (design of new micro-systems, use of a confocal microscope). That will be in order to perform combined thermal and velocity measurement with the help of fluorescent nano-particles seeded in the flow. He/she will have to propose physical explanations related to the experimental data. He/she will also involve in X ray instrumentation and void ratio measurements. Some background in LIF, PIV, micromachining and clean room environment will be appreciated. Applications will close as soon as a suitable candidate is found. Duration : one year
17/03/2014
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