The Experts below are selected from a list of 31242 Experts worldwide ranked by ideXlab platform
Jianghong Zhao - One of the best experts on this subject based on the ideXlab platform.
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effect of Supply Flow Rate on performance of pneumatic non contact gripper using vortex Flow
Experimental Thermal and Fluid Science, 2016Co-Authors: Jianghong ZhaoAbstract:Abstract The vortex gripper is a new kind of non-contact gripper, which geneRates negative pressure by blowing compressed air into a vortex cup through two tangential nozzles. It can provide an adequate suction force for handling a workpiece without contact. This gripper can avoid the disadvantages of traditional gripping devices, such as inducing mechanical scratches, local stress concentration, frictional static electricity, and blots on the workpiece. In this study, we experimentally and theoretically investigated the effect of Supply Flow Rate on the performance of the vortex gripper. First, we proposed three performance indexes for evaluating the properties of the vortex gripper: the maximum force, suspension region, and suspension stiffness. Then, we obtained a series of F–h (i.e., the suction force against the spacing between the gripper and the workpiece) curves at different Supply Flow Rates and the pressure distributions at the surface of the workpiece for different values of spacing h . Based on the experimental data, we analyzed the effect of the Supply Flow Rate on the maximum force, and by nondimensionalization of the F–h curves, the changes in the suspension region were assessed. Furthermore, we proposed an additive method of pressure distribution and deduced a simplified theoretical formula for suspension stiffness. In addition, from the perspective of the suspension stability of the workpiece, we evaluated the physical significance of the slope of the F–h curves after nondimensionalization. The findings of this study could help researchers to comprehend the operation of the vortex gripper and provide guidance for implementing the vortex gripper in practical applications.
Kazunori Nomura - One of the best experts on this subject based on the ideXlab platform.
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extraction and stripping of actinide elements with changes in Supply Flow Rate and nitric acid concentration using centrifugal contactors in single cycle solvent extraction system
Chemical Engineering Science, 2011Co-Authors: Masaumi Nakahara, Kazunori NomuraAbstract:Counter current experiments in a single cycle solvent extraction system were carried out with centrifugal contactors to study Flow Rate reductions in extraction solvent and stripping solution with a dissolver solution of irradiated mixed oxide (MOX) fuel. Uranium and Pu leaked to the raffinate with a 15% decrease in the extraction solvent Flow Rate, which brought about an accumulation of U and Pu in the co-decontamination section. The discharge of other actinide elements and fission products (FPs) in the raffinate was constant when the extraction solvent reduced by 15%. On the other hand, a 15% decrease in the stripping solution Flow Rate did not affect the stripping of U and Pu so greatly. The polymerization of Pu was not observed in the counter current experiments, and the time taken to change 2% of Pu(IV) to Pu polymers in the stripping section was evaluated. Simulation results based on these experiments showed that a high HNO3 concentration in the feed solution was advantageous for Np extraction, because Np oxidation progressed in the extraction section.
Shihcheng Hu - One of the best experts on this subject based on the ideXlab platform.
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airFlow characteristics in the outlet region of a vortex room air diffuser
Building and Environment, 2003Co-Authors: Shihcheng HuAbstract:Abstract For turbulent type clean rooms, terminal devices with high diffusion performance are required because the Supply Flow Rate is usually provided only in the margin value. Vortex diffuser is generally assumed with high diffusion performance. However, its detailed technology data are not available. In this study, the airFlow characteristics in the outlet region of a generic vortex diffuser were experimentally and numerically investigated. The zonal hybrid meshes were used in grid generation, where the regions around the disk and the guide vanes were meshed with tetrahedral cells, the inlet duct of the diffuser and the room space were meshed with hexahedra cells. The prismatic (or wedge) cells were used as the transitional cells to enable a change in cell type from hexahedra to tetrahedral. Such arrangement of the cell types has been found to be ideal for analysis of room air movement due to an air diffuser. Corresponding airFlow measurements were conducted by using a three-dimensional ultrasonic anemometer. In the region very adjacent to the ceiling ( 0.05 m from the ceiling), the velocity magnitude was conducted by using a hot-wire anemometer. The results show that the Flow pattern in the vicinity of outlet region for vortex diffuser is three-dimensional and highly turbulent. The experimental results were found to agree well with the results of the numerical analysis. The K value of the vortex diffuser investigated is in the range 2.1–2.3. It is concluded that the zonal hybrid meshes are well suited for analysis of the complicated Flow structure issuing from the vortex diffuser. This study also shows that the vortex diffuser has a greater entrainment ratio than that of a multi-cone circular ceiling diffuser, due to the influence of the stationary twists guide vanes. Therefore, the vortex diffuser is a good option as a terminal device for turbulent type clean room.
Graham Legge - One of the best experts on this subject based on the ideXlab platform.
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an experimental study of the Flow characteristics and velocity fields in an operating room with laminar airFlow ventilation
Journal of building engineering, 2020Co-Authors: Omid Ali Zarga, Osca Juina, Dexter Lyndo Sabusap, Graham LeggeAbstract:Abstract A critical aspect of the role of ventilation in hospital operating rooms (ORs) is the prevention of surgical site infection (SSI) which is largely attributable to airborne infection. Ventilation using clean filtered air is the primary means of airborne infection control. Many modern OR ventilation systems use laminar airFlow (LAF) for air distribution. Conventional LAF ventilation supplies air directly over the surgical area which creates a sterile zone and uses wall-mounted air returns located at low level. A problem avoided with this design is the formation of recirculation in the non-sterile zone which arises due to disruption of LAF. This recirculation can lead to entrainment of the contaminated room air to the Supply airFlow which can increase the risk of SSI. In order to prevent this entrainment, airFlow in the non-sterile zone has to be significantly altered. In this study, the application of ceiling returns and skirts in order to prevent the recirculation is experimentally investigated. AirFlow patterns were analyzed using smoke Flow visualization and particle image velocimetry (PIV). A novel laser sheet generator was used for illumination of the smoke particles. The effects of the Supply Flow Rate, skirt length, and percentage of ceiling-return Flow Rate on the recirculation were assessed using Taguchi method. The results show that the application of ceiling return can eliminate the recirculation. Ceiling-return Flow Rate has the greatest influence, followed by the Supply Flow Rate and the skirt. The findings of this study could contribute to the improvement of the conventional LAF ventilation design.
Nesreen Ghaddar - One of the best experts on this subject based on the ideXlab platform.
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displacement ventilation with cooled liquid desiccant dehumidification membrane at ceiling modeling and design charts
Energy, 2017Co-Authors: Mohamad Hout, Nesreen Ghaddar, Kamel Ghali, Nagham Ismail, Marco Simonetti, Giovanni Vincenzo Fracastoro, Joseph Virgone, Assaad ZoughaibAbstract:A novel transport model is developed for a space conditioned by a cooled liquid desiccant dehumidification membrane ceiling (LDMC-C) and displacement ventilation DV in which the space is divided into three zones: an occupied cool with fresh air zone; an upper recirculation zone; and a ceiling adjacent boundary layer zone where the air is drawn at the exhaust grill. The adjacent air boundary layer at the ceiling membrane predicted the latent and sensible heat transfer to the desiccant solution. The boundary model was validated experimentally in a climatic chamber. The developed model predicted of the LDMC-C/DV system operational parameters such as the Supply Flow Rate and temperature and the liquid desiccant concentration, Flow Rate, and inlet temperature that meet thermal comfort and air quality requirements. Extensive simulations were performed on a typical office load of 75 W/m2 to geneRate design charts of the system for three DV Supply air temperatures of 18, 20, and 22 °C to identify the appropriate DV Flow Rate and inlet desiccant (CaCl2) solution temperature that provide comfort and air quality and ensures that condensation is unlikely to occur. The LDMC sensible and latent load removal from the space load is directly read off the charts.
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performance evaluation of the displacement ventilation combined with evaporative cooled ceiling for a typical office in beirut
Energy Conversion and Management, 2015Co-Authors: Manar Younis, Kamel Ghali, Nesreen GhaddarAbstract:Abstract Displacement ventilation (DV) system combined with a novel evaporative cooled ceiling (ECC), Maisotsenko cycle (M-cycle), is a passive technique proposed to enhance the load removal in spaces beyond the conventional DV limit of 40 W/m 2 . In this study, predictive mathematical models of the conditioned space and the evaporative cooled ceiling were developed to study the performance of the integRated system. The integRated DV/ECC mathematical model was validated experimentally showing good prediction of ceiling temperature and room conditions at different space loads. A parametric study was done in order to study the limitations of the system, where it showed better efficiency at higher Supply Flow Rates and lower Supply air relative humidity. The validated DV/ECC system model was applied for a typical office in the city of Beirut, where a control stRategy of increasing the Supply Flow Rate was implemented to the DV system, while maintaining a stratification height of 1.5 m. The integRated system is opeRated only when the DV system cannot attain comfort in the space anymore. The load removal by the DV/ECC reached 50 W/m 2 , exceeding by 20% the maximum limit of 40 W/m 2 of the unaided DV system. Moreover, the proposed DV/ECC system resulted in 36.2% reduction in electric energy consumption in the summer months when compared with a conventional DV and chilled ceiling system.
