Numerical Study on the Characteristics of Natural Supercavitation by Planar Symmetric Cavitators With Streamlined Headforms

A novel supercavitation-based device named Rotational Supercavitating Evaporator (RSCE) was recently designed for desalination. In order to improve the blade shape of rotational cavitator in RSCE for performance optimization and then design three-dimensional blades, two-dimensional numerical simulations are conducted on the supercavitating flows (with cavitation number ranging from 0.055 to 0.315) around six planar symmetric cavitators with different streamlined headforms utilizing k – ε – v′2 – f turbulence model and Schnerr-Sauer cavitation model. We obtain the characteristics of natural supercavitation for each cavitator, including the shape and resistance characteristics and the mass transfer rate from liquid phase to vapor phase. The effects of the shape of the headform on these characteristics are analyzed. The results show that the supercavity sizes for most cavitators with streamlined headforms are smaller than that for wedge-shaped cavitator, except for the one with the profile of the forebody concaving to the inside of the cavitator. Cavitation initially occurs on the surface of the forebody for the cavitators with small curvature of the front end. Even though the pressure drag of the cavitator with streamlined headform is dramatically reduced compared with that of wedge-shaped cavitator, the pressure drag still accounts for most of the total drag. Both the drag and the mass transfer rate from liquid phase to vapor phase are in positive correlation with the supercavity size, indicating that the cavitators with the elliptic and hyperbolic cosine-type forebodies could be utilized for the optimal design of three-dimensional blade shape of RSCE.

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Evaluation of the mass transfer rate using computer simulation in a three-dimensional interwoven hollow fiber-type bioartificial liver

Biotechnology Letters ◽

10.1007/s10529-018-2609-1 ◽

2018 ◽

Vol 40 (11-12) ◽

pp. 1567-1578 ◽

Cited By ~ 2

Author(s):

Ryoichi Sakiyama ◽

Hiroyuki Hamada ◽

Brandon Blau ◽

Nora Freyer ◽

Katrin Zeilinger ◽

...

Keyword(s):

Mass Transfer ◽

Computer Simulation ◽

Hollow Fiber ◽

Transfer Rate ◽

Fiber Type ◽

Mass Transfer Rate ◽

Three Dimensional ◽

Bioartificial Liver

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Granulated Carbon Nanotubes as the Catalyst Support for Pt for the Hydrogenation of Nitrobenzene

Australian Journal of Chemistry ◽

10.1071/ch09162 ◽

2010 ◽

Vol 63 (1) ◽

pp. 131 ◽

Cited By ~ 10

Author(s):

Shao Jin ◽

Weizhong Qian ◽

Yi Liu ◽

Fei Wei ◽

Dezeng Wang ◽

...

Keyword(s):

Carbon Nanotubes ◽

Mass Transfer ◽

Catalytic Activity ◽

Activated Carbon ◽

Liquid Phase ◽

Transfer Rate ◽

High Selectivity ◽

Mass Transfer Rate ◽

Catalyst Support ◽

Liquid Phase Hydrogenation

Granulated Pt/carbon nanotubes (CNTs) were found to have a much better catalytic activity in the liquid phase hydrogenation of nitrobenzene than Pt/activated carbon (AC). The granulated CNTs had much larger pores than the AC particles, which gave a faster mass transfer rate of H2 that helped produce aniline with high selectivity.

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Numerical Study of Natural Convective Heat and Mass Transfer in an Inclined Porous Media

Engineering, Technology & Applied Science Research ◽

10.48084/etasr.2179 ◽

2018 ◽

Vol 8 (4) ◽

pp. 3223-3227

Author(s):

A. Latreche ◽

M. Djezzar

Keyword(s):

Mass Transfer ◽

Heat And Mass Transfer ◽

Transfer Rate ◽

Numerical Study ◽

Mass Transfer Rate ◽

Momentum Conservation ◽

Conservation Equation ◽

Coupled Equations ◽

Dimensional Parameters ◽

Finite Volume Approach

In this study, two dimensional natural convection heat and mass transfer generated in an inclined rectangular porous cavity filled with Newtonian fluid has been investigated numerically. The cavity is heated and cooled along horizontal walls while the solutal gradient is imposed horizontally. The physical model for the momentum conservation equation makes use of the Darcy model, and the set of coupled equations is solved using a finite volume approach. The successive-under-relaxation (SUR) method is used in the solution of the stream function equation. The results are presented graphically in terms of streamlines, isotherms and iso-concentrations. The heat and mass transfer rate in the cavity is measured in terms of the average Nusselt and Sherwood numbers for various non-dimensional parameters.

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Mass Transfer Rate Enhancement in Sparged Vessel for Ammonia-Water Nano-Fluid in VARS by Adding Nanoparticles

Volume 11: Heat Transfer and Thermal Engineering ◽

10.1115/imece2020-24382 ◽

2020 ◽

Author(s):

Rahul Bhujbal ◽

Sanjay Nakate ◽

Sunil V. Dingare

Keyword(s):

Mass Transfer ◽

Transfer Rate ◽

Numerical Study ◽

Mass Transfer Rate ◽

Solution Flow Rate ◽

Low Grade ◽

Efficient Design ◽

Operation Condition ◽

Solution Flow ◽

Ammonia Water

Abstract The refrigeration systems are used in domestic and commercial freezing applications. These systems are needed to be used energy efficiently to get the economic operation condition. The vapor compression refrigeration cycle (VCR) is getting replaced by vapor absorption refrigeration system (VARS) as they can use low grade energy. This VARS can be used by making use of waste energy in the form of heat which is readily available for many applications. Performance of the VARS is dependent on the generator and absorber performance. In absorber it is based on the amount of refrigerant absorbed and the solution flow rate. Experimental and Numerical study of bubble absorber and effect of nanoparticle on ammonia water mass transfer is carried out. In this study, different designs for the absorber chamber are viewed and compared together, based on the research did earlier. Looking at the aspects of bubble type absorber designs, these designs give better mass transfer performance as compared to other designs. These designs may be improved to get the energy efficient design of the absorber. Present study includes the enhancement of mass transfer rate by the addition of nanoparticles using aluminum oxide (Al2O3). Here, sparged vessels with NH3-H2O binary fluid are arranged with varying percentage of nanoparticle (Al2O3). This study includes the study of mass transfer enhancements by using nanoparticles. Based on the experimental results carried out for the varying mass flow rates it is found that the mass transfer rate is enhanced significantly, it is because the interfacial area is enhanced by the addition of nanoparticles to the base fluids.

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Numerical Study on Boiling Mechanism and Rapid Phase Transfer Phenomenon of LNG Discharging on Water

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.516-517.97 ◽

2012 ◽

Vol 516-517 ◽

pp. 97-106 ◽

Cited By ~ 1

Author(s):

Bin Zhang ◽

Wan Qing Wu ◽

Jian Wei Zhang

Keyword(s):

Mass Transfer ◽

Transfer Rate ◽

Water Surface ◽

Phase Transfer ◽

Numerical Study ◽

Mass Transfer Rate ◽

Initial Time ◽

Rapid Phase ◽

Boiling Mechanism ◽

Superheat Limit

Abstract. Aiming at analyzing boiling mechanism and confirming rapid phase Abstract. Aiming at analyzing boiling mechanism and confirming rapid phase transfer (RPT) taking place conditions of LNG discharging on water. The models of pool spreading, heat and mass transfer rate and LNG’s property are coupled in this paper. The conditions of RPT has been confirmed, which included LNG directly contacting with water and the water temperature should higher than LNG’s superheat limit temperature, but the RPT would not take place if the LNG boils on ice. The model of LNG discharging on water has been established in this paper, which is used to simulate Boe and Burro-9 experiments. The results showed that the models can simulate evaporation and boiling rate well, and can be used in predicting the initial time of RPT happening when the discharging process is calm and the location of discharging is near the water surface.

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Discrete-differential modelling of biofilm structure

Water Science & Technology ◽

10.2166/wst.1999.0341 ◽

1999 ◽

Vol 39 (7) ◽

pp. 115-122 ◽

Cited By ~ 49

Author(s):

C. Picioreanu ◽

M. C. M. van Loosdrecht ◽

J. J. Heijnen

Keyword(s):

Mass Transfer ◽

Bacterial Growth ◽

Transfer Rate ◽

Mass Transfer Rate ◽

Three Dimensional ◽

Bacterial Growth Rate ◽

Biofilm Growth ◽

Low Mass ◽

Deformation Stress ◽

Biofilm Structure

A fully quantitative two- and three-dimensional approach for biofilm growth and structure formation has been developed. The present model incorporates the flow over the irregular biofilm surface, convective and diffusive mass transfer of substrate, bacterial growth and biomass spreading. A future model will also include a mechanism for biofilm detachment due to biofilm deformation stress. Any arbitrary shape of the carrier surface can be accommodated in the model, as well as multispecies and multisubstrate biofilms. Results of model simulations show that the ratio between nutrient transfer rate to the biofilm and the bacterial growth rate influences to a great extent the biofilm roughness and porosity. A low mass transfer rate, i.e., low Reynolds numbers or high values of Thiele modulus, results in the development of a rough and open biofilm. When the biofilm growth is not limited by the substrate availability but by the rate of bacterial metabolism, the biofilm forms as a compact and homogeneous structure. The multidimensional biofilm modelling approach we used is very suitable for theoretical investigation of factors that affect biofilm structure and ecology.

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Hot Spots Drift in Synchronous and Asynchronous Polars: Results of Three-Dimensional Numerical Simulation

Galaxies ◽

10.3390/galaxies9040110 ◽

2021 ◽

Vol 9 (4) ◽

pp. 110

Author(s):

Dmitry Bisikalo ◽

Andrey Sobolev ◽

Andrey Zhilkin

Keyword(s):

Numerical Simulation ◽

Mass Transfer ◽

Temperature Distribution ◽

Hot Spots ◽

Transfer Rate ◽

Hot Spot ◽

Mass Transfer Rate ◽

Three Dimensional ◽

Jet Trajectory ◽

Dominant Influence

In this paper, the characteristics of hot spots on an accretor surface are investigated for two types of polars: the eclipsing synchronous polar V808 Aur and the non-eclipsing asynchronous polar CD Ind in configuration of an offset and non-offset magnetic dipole. The drift of hot spots is analyzed based on the results of numerical calculations and maps of the temperature distribution over the accretor surface. It is shown that a noticeable displacement of the spots is determined by the ratio of ballistic and magnetic parts of the jet trajectory. In the synchronous polar, the dominant influence on the drift of hot spots is exerted by variations in the mass transfer rate, which entail a change in the ballistic part of the trajectory. It was found that when the mass transfer rate changes within the range of 10−10M⊙/year to 10−7M⊙/year, the displacement of the hot spot in latitude and longitude can reach 30∘. In the asynchronous polar, a change in the position of hot spots is mainly defined by the properties of the white dwarf magnetosphere, and the displacement of hot spots in latitude and longitude can reach 20∘.

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