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Hernandez Sanchez M.D.R.,Agro ParisTech | Cuvelier M.-E.,French National Institute for Agricultural Research | Turchiuli C.,CNAM
Journal of Food Engineering | Year: 2015

The formulation and structure of initial liquid emulsion have an impact on the efficiency of encapsulation (encapsulated oil quantity) in spray dried particles (dried emulsions) and must be adapted to spray drying. Two different protocols were tested varying the concentration of emulsifier (Tween® 20), conditions of homogenization and concentration of wall material (Maltodextrin and Agave Inulin). The concentration of emulsifier and wall material should allow avoiding micelle formation or coalescence. Results show that it was possible to produce stable emulsions with an oil droplet size around 2. μm containing 40% w/w of total dry matter (g/100. g emulsion) using maltodextrin as wall material and 3.5% Tween® 20 (3.5. g/100. g oil) or using Agave Inulin in emulsions with a total dry mater content of 50% w/w (50. g/100. g emulsion) with a minimal concentration of emulsifier (1.17. g/100. g oil). The spray drying of these emulsions produced fine powders (<22. μm) with a monodispersed size distribution and good oil encapsulation efficiency (>88%). © 2015. Source

Bore T.,Laboratoire Central des Ponts et Chaussees | Taillade F.,Laboratoire Central des Ponts et Chaussees | Placko D.,French National Center for Scientific Research | Himbert M.,CNAM
AIP Conference Proceedings | Year: 2010

This paper presents both theoretical and experimental aspects of a measurement problem in the field of non-destructive evaluation. The purpose of our work is to develop a capacitive probe devoted to post-tensioned cable inspection, mainly for bridge monitoring applications. In this paper will successively be presented the industrial problem, the current probe in use, and an original modeling achieved for sensor design and signal processing. In a first step, we will compare the experimental and theoretical data obtained with different 'devices under test' configurations. Then we will discuss about both capabilities of our direct model, on one hand to provide some help in sensor design improvements and on other hand to be inserted in an inverse problem scheme, to get an estimate of some interesting data of our problem from the measured signals. © 2010 American Institute of Physics. Source

Joseph P.,Institute AeroTechnique IAT | Amandolese X.,CNAM | Aider J.-L.,ESPCI ParisTech
Experiments in Fluids | Year: 2012

This paper highlights steady and unsteady measurements and flow control results obtained on an Ahmed model with slant angle of 25° in wind tunnel. On this high-drag configuration characterized by a large separation bubble along with energetic streamwise vortices, time-averaged and time-dependent results without control are first presented. The influence of rear-end periodic forcing on the drag coefficient is then investigated using electrically operated magnetic valves in an open-loop control scheme. Four distinct configurations of flow control have been tested: rectangular pulsed jets aligned with the spanwise direction or in winglets configuration on the roof end and rectangular jets or a large open slot at the top of the rear slant. For each configuration, the influence of the forcing parameters (non-dimensional frequency, injected momentum) on the drag coefficient has been studied, along with their impact on the static pressure on both the rear slant and vertical base of the model. Depending on the type and location of pulsed jets actuation, the maximum drag reduction is obtained for increasing injected momentum or well-defined optimal pulsation frequencies. © Springer-Verlag 2011. Source

Amandolese X.,CNAM | Vartanian C.,GIE S2A Aerospace acoustics Wind Tunnel Complex
Journal of Wind Engineering and Industrial Aerodynamics | Year: 2010

3/4 open jet wind tunnels are subjected to undesired low frequency pressure and velocity fluctuations at distinct flow velocities. The aim of this paper is to present recent research done in the full scale automotive aero-acoustic facility of the S2A wind tunnel complex in order to characterise the physical mechanism causing the fluctuations, to clarify their impact on the aerodynamic measurements and to validate solutions that allow high quality aerodynamic and acoustic measurements over the entire velocity range of the wind tunnel. Four areas of significant oscillations have been detected in the full scale S2A wind tunnel for wind velocities between 10 and 60. m/s. Those fluctuations are due to successive lock-ins of the wind speed dependent shear layer instability of the jet, with acoustic resonant frequencies of the wind tunnel. Various solutions have been tested in order to assess their impact on the fluctuations and on the quality of the aerodynamic measurements. A less protruding solution than classical vortex generator has been validated. It is made of two rectangular flaps along the upper edge of the nozzle exit, with a small plunging angle. © 2010 Elsevier Ltd. Source

Aider J.-L.,ESPCI ParisTech | Joseph P.,Institute AeroTechnique IAT | Ruiz T.,PSA Peugeot Citroen | Gilotte P.,Plastic Omnium Auto Exterieur Services POAES | And 3 more authors.
International Journal of Flow Control | Year: 2014

This paper presents experimental flow control results obtained on a full-scale production car in a wind tunnel. The aim of this paper is to demonstrate the feasibility of controlling the separated flow over the rear part of the car by using pulsed micro-jets. Pulsed micro-jets are produced by hybrid actuators mixing both standard and MEMS (Micro Electro Mechanical Systems) technology. Both actuation frequency and injected momentum are studied. Experiments show a small influence on the drag force (less than 1% reduction), but a stronger one on the lift force (up to 9% reduction). Wall pressure coefficients measurements highlight the suppression of the recirculation bubble over the rear window, along with a reinforcement of the longitudinal C-pillars vortices. Spectral measurements in the shear layer above the rear window show that most efficient control frequencies match the shear layer instability frequency, and that the actuation suppresses the energetical contribution associated with the recirculation bubble frequency. Additional measurements demonstrate that a minimum threshold value of the momentum coefficient is needed for the flow actuation to be efficient. This is the first experimental evidence of the efficiency of micro perturbations (380μm thick micro-nozzles) to control flow separation on a full- scale production car. This is a very important step in the perspective of future applications of flow control in automotive industry to improve aerodynamics performances and reduce CO2emissions. Source

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