Abstract: The chaotic behavior of natural convection flows makes possible the use of instability to modify heat transfer. The key idea is to perturb the boundary layers by thermal perturbations in order to obtain resonant phenomena and thus amplify the effects of these disturbances.
Keywords: Experimental convection, buoyant flows, turbulence, instabilities.
----
Full description:
Improving the energy performance of a cabin (transport, residential, tertiary, etc.) is a major concern for its impact on consumption and greenhouse gas (GHG) emissions. The manipulation of natural convection flows (imortant energy transfer mechanism in these devices) in order to optimize and control of heat transfers appears therefore of great interest. Previous works in the laboratory (Skurtys PhD thesis or Thomas PhD thesis, for example) have demonstrated the feasibility and pertinence of such an approach. The chaotic nature of natural convection phenomenon makes these flows very sensitive to disturbances. This aspect must be exploited through laboratory demonstrators.
The candidate will work to examine the response to a given excitation and optimize it in terms of energy efficiency. This is essentially experimental study to be conducted on two reference test benches (differentially heated cavities or DHC) available in the laboratory: the first one is of small size (50-cm-DHC) allowing the study of the first flow bifurcations. The second one is a large and unique DHC (4m-high-DHC) dedicated to the study of natural convection flows in turbulent regime on the scale of an actual cabin.
In this study, the fluid (air) is locally disturbed by controlled thermal excitation amplitude and frequency. The problem of optimal positioning of the disturbance and the analysis of the response aiming at actively controlling heat transfers will be investigated based on the expertise of the team especially on thermal metrology (micro-thermocouples, micro-flow meters, LDV and PIV). It could be combined by numerical simulations (Navier-Stokes), parametric sensitivity studies, carried out in collaboration with longstanding academic partners.
RTP Slot Gacor memang menjadi pilihan menarik bagi banyak pemain karena peluang menangnya yang lebih besar. Dengan persentase RTP Slot Tertinggi, pemain bisa merasa lebih percaya diri saat bermain dan berharap pada peluang yang lebih baik. Saat bermain di RTP Slot Online, sensasi adrenalin saat melihat peluang kemenangan yang tinggi menjadi pengalaman tersendiri. Slot RTP Tertinggi menawarkan stabilitas dan frekuensi kemenangan yang sangat dinantikan banyak pemain.