Effects of axial rectangular groove on turbulent Taylor-Couette flow from analysis of experimental data
Article dans une revue avec comité de lecture
The relationship between a rough or structured surface topology and its hydraulic resistance was analysed in the case of fully turbulent Taylor-Couette flow at fixed radii ratio η = 0.9375 and for Reynolds numbers Re i from 2×10 4 to 13×10 4. Three configurations of inner cylinder having 6, 12 and 24 grooves of a same rectangular shape and regularly distributed were compared to a reference smooth cylinder with only inner cylinder rotating. Such configurations are common in electric motors of high power density where a better understanding of flow pattern and heat transfer is essential to enhance their design and to develop appropriate cooling system. Torque and pointwise velocity measurements were performed. The effects of the flow modulations induced by the grooves on the friction coefficient and the flow features were examined. The results showed significant difference in the flow pattern and an increase of the friction coefficient with increasing the groove number. However, the drag-increasing capacity of each groove was further reduced by increasing the groove number. It was also found that, the local scaling exponent between friction coefficient and Reynolds number was insensitive to the present surface roughness, suggesting that the bulk flow contribution is similar for all the four configurations.
Showing items related by title, author, creator and subject.
Experimental investigation of an actively controlled automotive cooling fan using steady air injection in the leakage gap Article dans une revue avec comité de lectureAZZAM, Tarik; PARIDAENS, Richard; RAVELET, Florent; KHELLADI, Sofiane; OUALLI, Hamid; BAKIR, Farid (SAGE Publications, 2017)In an axial fan, a leakage flow driven by a pressure gradient between the pressure side and the suction side occurs in the gap between the shroud and the casing. This leakage flow is in the opposite direction to the main ...
Influence of design parameters on the global performances of low-speed counter-rotating axial-flow fans Communication avec acteWANG, Juan; RAVELET, Florent; BAKIR, Farid (2014)The present work aims at experimentally investigating the effects of some parameters on the performances of a counter-rotating stage, and on the instationary flow between the rotors. Three counter-rotating fans, which have ...
Experimental study of blade rigidity effects on the global and the local performances of a thick blades axial-flow fan Communication avec acteNOURI, Hussain; RAVELET, Florent; SARRAF, Christophe; BAKIR, Farid (ASME, 2010)An experimental investigation on the aerodynamic performances of thick blades axial-flow fans was carried out in this study. Two fans are considered, the first one is rotomoulded (in plastic) and the second one is milled ...
Improved Aerodynamics of a Hollow-Blade Axial Flow Fan by Controlling the Leakage Flow Rate by Air Injection at the Rotating Shroud Article dans une revue avec comité de lecturePEREIRA, Michaël; RAVELET, Florent; AZZOUZ, Kamel; AZZAM, Tarik; OUALLI, Hamid; KOUIDRI, Smaïne; BAKIR, Farid (MDPI AG, 2021)Axial flow fans are used in many fields in order to ensure the mass and heat transfer from air, chiefly in the heating, ventilation and air conditioning industry (HVAC). A more proper understanding of the airflow behavior ...
Article dans une revue avec comité de lectureRAVELET, Florent; DANLOS, Amélie; BAKIR, Farid; CROCI, Kilian; KHELLADI, Sofiane; SARRAF, Christophe (MDPI AG, 2020)The present study focuses on the inception, the growth, and the potential unsteady dynamics of attached vapor cavities into laminar separation bubbles. A viscous silicon oil has been used in a Venturi geometry to explore ...