scholarly journals Numerical Study of Electrostatic Desalting Process Based on Droplet Collision Time

Processes ◽  
2021 ◽  
Vol 9 (7) ◽  
pp. 1226
Author(s):  
Marco A. Ramirez-Argaez ◽  
Diego Abreú-López ◽  
Jesús Gracia-Fadrique ◽  
Abhishek Dutta
Keyword(s):  
Field Strength ◽  
Moisture Content ◽  
Droplet Size ◽  
Electrostatic Field ◽  
Numerical Study ◽  
Force Balance ◽  
Main Process ◽  
Cfd Model ◽  
Collision Time ◽  
Oil Viscosity

The desalting process of an electrostatic desalting unit was studied using the collision time of two droplets in a water-in-oil (W/O) emulsion based on force balance. Initially, the model was solved numerically to perform a process analysis and to indicate the effect of the main process parameters, such as electric field strength, water content, temperature (through oil viscosity) and droplet size on the collision time or frequency of collision between a pair of droplets. In decreasing order of importance on the reduction of collision time and consequently on the efficiency of desalting separation, the following variables can be classified such as moisture content, electrostatic field strength, oil viscosity and droplet size. After this analysis, a computational fluid dynamics (CFD) model of a biphasic water–oil flow was developed in steady state using a Eulerian multiphase framework, in which collision frequency and probability of coalescence of droplets were assumed. This study provides some insights into the heterogeneity of a desalination plant which highlights aspects of design performance. This study further emphasizes the importance of two variables as moisture content and intensity of electrostatic field for dehydrated desalination by comparing the simulation with the electrostatic field against the same simulation without its presence. The overall objective of this study is therefore to show the necessity of including complex phenomena such as the frequency of collisions and coalescence in a CFD model for better understanding and optimization of the desalting process from both process safety and improvement.

scholarly journals Numerical Study toward Optimization of Spray Drying in a Novel Radial Multizone Dryer

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Umair Jamil Ur Rahman ◽  
Artur Krzysztof Pozarlik ◽  
Thomas Tourneur ◽  
Axel de Broqueville ◽  
Juray De Wilde ◽  
...  
Keyword(s):  
Spray Drying ◽  
Droplet Size ◽  
Separation Efficiency ◽  
Numerical Study ◽  
Three Dimensional ◽  
Droplet Size Distribution ◽  
Vortex Chamber ◽  
Temperature Pattern ◽  
Multiphase Model ◽  
Drying Technology

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.

Numerical Study of Pitch Angle on H-Type Vertical Axis Wind Turbine

2012 ◽  
Vol 499 ◽  
pp. 259-264
Author(s):  
Qi Yao ◽  
Ying Xue Yao ◽  
Liang Zhou ◽  
S.Y. Zheng
Keyword(s):  
Wind Turbine ◽  
Pitch Angle ◽  
Numerical Study ◽  
Vertical Axis ◽  
Azimuth Angle ◽  
Power Coefficient ◽  
Cfd Model ◽  
Vertical Axis Wind Turbine ◽  
Sliding Mesh ◽  
Mesh Technique

This paper presents a simulation study of an H-type vertical axis wind turbine. Two dimensional CFD model using sliding mesh technique was generated to help understand aerodynamics performance of this wind turbine. The effect of the pith angle on H-type vertical axis wind turbine was studied based on the computational model. As a result, this wind turbine could get the maximum power coefficient when pitch angle adjusted to a suited angle, furthermore, the effects of pitch angle and azimuth angle on single blade were investigated. The results will provide theoretical supports on study of variable pitch of wind turbine.

scholarly journals Simulations and Experiments of the Soil Temperature Distribution after 2.45-GHz Short-Time Term Microwave Treatment

Agriculture ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 933
Author(s):  
Xiaohe Sun ◽  
Changyuan Zhai ◽  
Shuo Yang ◽  
Haolin Ma ◽  
Chunjiang Zhao
Keyword(s):  
Soil Moisture ◽  
Field Strength ◽  
Moisture Content ◽  
Soil Temperature ◽  
Output Power ◽  
Soil Moisture Content ◽  
Microwave Treatment ◽  
Soil Treatment ◽  
Internal Temperature ◽  
Soil Disinfection

Microwave treatment is a green and pollution-free soil disinfection method. The application of microwaves to disinfect soil before cultivation is highly important to increase crop yields and protect the ecological environment. The electromagnetic field is an important parameter influencing the soil temperature field in the process of microwave soil treatment, and the change in soil temperature directly affects soil disinfection. Therefore, this article carried out research on the heating pattern in North China loess due to microwave treatment. First, COMSOL software was employed to simulate the microwave soil treatment process to analyze microwave penetration into soil. Second, with the application of microwaves at the designed frequency produced with a 2.45-GHz tunable microwave generating microdevice, soil with water contents of 0%, 10%, 20%, and 30% was treated for 10~60 s (at 10-s time intervals), and experiments on the influence of the microwave output power, treatment time, and soil moisture content on the soil temperature were performed via the controlled variable method. The simulation results indicate that with increasing soil moisture content, the microwave frequency inside the soil model increases, and the electric field intensity value decreases in the model at the same depth. After microwaves traverse through the 20-cm soil model, the incident field strength is three orders of magnitude lower than the outgoing field strength. The results of the microwave soil treatment experiment reveal that: (1) Compared to microwave output power levels of 1.8 and 1.6 kW, a level of 2 kW is more suitable for microwave soil disinfection. (2) After treatment, the highest temperature occurs on the soil surface, not within the soil. (3) The location of the highest soil internal temperature after microwave treatment increasingly approaches the soil surface with increasing soil moisture content, and the microwave output power does not affect the location of the highest soil internal temperature. Combining the electromagnetic field simulation and microwave soil treatment experiment results, it was found that the higher the field strength is, the higher the temperature value, and the highest soil internal temperature after microwave treatment often occurs at the first electromagnetic wave peak.

Improving electrospinning process by numerical analysis of 3-D computer models

2019 ◽  
Vol 38 (4) ◽  
pp. 1098-1110
Author(s):  
Anna Firych-Nowacka ◽  
Krzysztof Smolka ◽  
Sławomir Wiak
Keyword(s):  
Field Strength ◽  
Electric Field ◽  
Field Intensity ◽  
Electrostatic Field ◽  
Electric Field Intensity ◽  
Computer Models ◽  
Electrospinning Process ◽  
Strength Analysis ◽  
Original Solution ◽  
Content Type

Purpose Electrospinning is a method of the polymer super thin fibres formation by the electrostatic field. The distribution of electrostatic field affects the effectiveness of the electrospinning. Design/methodology/approach This paper presents various computer models that can improve the electrospinning process. The possibilities of modelling the electrostatic field in the design of electrospinning equipment are presented. Findings In the research part, the one focussed on finding a cylinder-shaped collector structure to limit the adverse effect of an uneven distribution of the electric field intensity on the collector. Originality/value The paper concerns the improvement of the electrospinning process with the use of electrostatic field modelling. In the first part, several possible applications of electrostatic models have been indicated, thanks to which the efficiency of the process has been improved. The original solution of the collector geometry was presented, which according to the authors, in comparison with previous models, gives the most promising results. In this solution, it was possible to obtain an even distribution of the electric field intensity while removing the unfavourable effect of the field strength increase on the outer edges of the collector. The most important aspect in this paper is electric field strength analysis.

scholarly journals Effect of Soil Moisture Content and End-Effector Speed on Pick-up Force and Lump Damage for Seedling Transplanting

2019 ◽  
Vol 1 (3) ◽  
pp. 343-356 ◽  
Author(s):  
Mohamed ◽  
Liu
Keyword(s):  
Soil Moisture ◽  
Moisture Content ◽  
Soil Moisture Content ◽  
Soil Condition ◽  
Penetration Resistance ◽  
Force Balance ◽  
High Moisture Content ◽  
High Moisture ◽  
End Effector ◽  
End Effectors

Efficient transplanting has been identified as one of the essential steps towards achieving an increased yield in the farm. However, many factors are affecting these processes such as soil moisture content and the speed of pickup. This study was carried out to investigate the effect of different soil moisture content and pickup speeds on pickup force, balance, resistance, and lump damage during transplanting of seedlings. The results showed that penetration resistance was inversely proportional to the speed and soil moisture content. The highest penetration resistance (38 N) values were recorded under the lowest speed (0.5 mm/s) at the low moisture content; whereas, the lowest penetration resistance was obtained at highest speed (10 mm/s) under high moisture content. The highest pick-up force resistance values were recorded under the lowest speed (0.5 mm/s) at low moisture content than the lowest pick-up force resistance of 1.4 N at (10 mm/s) under the high moisture content. On the other hand, an increase of pick-up force led to a decrease in the pick-up force resistance. The pick-up damage and the pick-up speed are directly proportional—nevertheless, the former increased with a decreasing soil moisture content. The highest pick-up damage values (82%) were observed under the top-most speed (10 mm/s) at high moisture content. It can be concluded that for successful auto-transplanting of seedling the soil condition, the force applied and speed should be taken into consideration. This work will implement an effective seedling-picking performance and basis for the optimal design of end-effectors.

Investigation of ammonia and hydrogen as CO2-free fuels for heavy duty engines using a high pressure dual fuel combustion process

2020 ◽  
pp. 146808742096787
Author(s):  
Stephanie Frankl ◽  
Stephan Gleis ◽  
Stephan Karmann ◽  
Maximilian Prager ◽  
Georg Wachtmeister
Keyword(s):  
High Pressure ◽  
High Pressures ◽  
Numerical Study ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Dual Fuel ◽  
Parameter Study ◽  
Fuel Injector ◽  
Cfd Model ◽  
Pilot Fuel

This work is a numerical study of the use of ammonia and hydrogen in a high-pressure-dual-fuel (HPDF) combustion. The main fuels (hydrogen and ammonia) are direct injected and ignited by a small amount of direct injected pilot fuel. The fuels are injected using a dual fuel injector from Woodward L’Orange, which can induce two fuels independently at high pressures up to 1800 bar for the pilot fuel and maximum 500 bar for the main. The numerical CFD-model gets validated for of hydrogen-HPDF with experimental data. Due to safety issues at the test rig it was not possible to use ammonia in the experiments, so it is modelled using the numerical model. It is assumed that the CFD-model also gives qualitative correct results for the use of ammonia as main fuel, so a parameter study of ammonia-HPDF is made. The results for the hydrogen-HPDF show, that hydrogen can be used in the engine without any further modifications. The combustion is very stable, and the hydrogen ignites almost immediately when it enters the combustion chamber. The results of the ammonia combustion indicate, that the HPDF combustion mode can handle ammonia effectively. It seems beneficial to inject the ammonia at higher pressures than hydrogen. Also pre-heating the ammonia can increase the combustion efficiency.

Numerical and Experimental Study of the Evaporation and Solid Layer Formation of a Bi-Component Droplet Under Various Drying Conditions

2014 ◽  
Author(s):  
Holger Grosshans ◽  
Matthias Griesing ◽  
Srikanth R. Gopireddy ◽  
Werner Pauer ◽  
Hans-Ulrich Moritz ◽  
...  
Keyword(s):  
Droplet Size ◽  
Mass Fraction ◽  
Numerical Study ◽  
Droplet Evaporation ◽  
Droplet Surface ◽  
Parameter Study ◽  
Layer Formation ◽  
Gas Temperature ◽  
Solid Layer ◽  
Initial Droplet

This paper presents a combined experimental and numerical study of the evaporation and solid layer formation of a single bi-component mannitol-water droplet in air. For spherically symmetric droplets, the problem is described mathematically by the unsteady, one-dimensional conservation equations of mass and energy. The effect of the formation of a solid layer at the droplet surface on the droplet evaporation and thermal diffusion rate is included in the present approach. The simulations are validated by comparison with experiments using acoustically levitated droplets. The study includes initial droplet diameters varying from 350 to 450 μm, gas temperatures ranging from 80 to 120 °C, and the initial mannitol mass fraction inside the droplet varies from 0.05 to 0.15. The numerical results are analyzed to identify the occurrence of solid layer formation, and the temporal evolutions of both the droplet size and mass are presented. A parameter study of the initial gas temperature, the initial droplet size, and the initial mannitol mass fraction inside the droplet on droplet evaporation and solid layer formation is presented. The present model accurately captures the initial stages of droplet drying under all conditions investigated.

Experimental Study of Finding Best Way of Radiation Seeds with HVEF

2011 ◽  
Vol 365 ◽  
pp. 440-444
Author(s):  
Jue Hang ◽  
Xin Chen ◽  
Jian Ping Xiong
Keyword(s):  
Experimental Study ◽  
Field Strength ◽  
High Voltage ◽  
Electrostatic Field ◽  
Radiation Transport ◽  
Clc Number ◽  
Document Code ◽  
Mathematical Derivation ◽  
Radiation Time ◽  
Germination Stage

Norder to find the best high-voltage electrostatic radiation seed program, to select two different kinds of cucumbers, vegetables, paddy rice seeds, each seed be divided into 5 experimental groups, and be treated by high voltage electrostatic field (HVEF) at different field strength and time, and testing and statistics of the seeds vigour at germination stage. The results indicated that the greater the radiation field to same seed, the shorter radiation time is required, and vice versa. For each species, E•t tends to a constant (the constant is different in different species). Be proved by mathematical derivation that the HVEF radiation transport essentially energy to the seed, and then will be able to find the best way for HVEF radiation seeds. CLC number: S129 Document code: A.

Numerical Simulation of Black Liquor Spray Characteristics

2002 ◽  
Author(s):  
Thomas D. Foust ◽  
Kurt D. Hamman ◽  
Brent A. Detering
Keyword(s):  
Droplet Size ◽  
Volume Fraction ◽  
Numerical Study ◽  
Black Liquor ◽  
Flow Distribution ◽  
Physical Models ◽  
Spray Characteristics ◽  
Two Phase ◽  
Vof Model ◽  
Sheet Breakup

The performance and capacity of Kraft recovery boilers is sensitive to black liquor velocity, droplet size and flow distribution in the furnace. Studies have shown that controlling droplet size and flow distribution improves boiler efficiency while allowing increased flight drying and devolatilization, and decreased carryover. The purpose of this study is to develop a robust two-phase numerical model to predict black liquor splashplate nozzle spray characteristics. A three-dimensional time dependent numerical study of black liquor sheet formation and sheet breakup is described. The volume of fluid (VOF) model is used to simulate flow through the splashplate nozzle up to initial sheet breakup and droplet formation. The VOF model solves the conservation equations of volume fraction and momentum utilizing the finite volume technique. Black liquor velocity, droplet size and flow distribution over a range of operating parameters are simulated using scaled physical models of splashplate nozzles. The VOF model is compared to results from a flow visualization experiment and experimental data found in the literature. The details of the simulation and experimental results are presented.

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