scholarly journals Performance Characterization of the UAV Chemical Application Based on CFD Simulation

Agronomy ◽  
2019 ◽  
Vol 9 (6) ◽  
pp. 308 ◽  
Author(s):  
Hang Zhu ◽  
Hongze Li ◽  
Cui Zhang ◽  
Junxing Li ◽  
Huihui Zhang
Keyword(s):  
Wind Speed ◽  
Correlation Coefficient ◽  
Cfd Simulation ◽  
Least Square Method ◽  
Least Square ◽  
Universal Method ◽  
Discrete Phase Model ◽  
Chemical Application ◽  
Distance Model ◽  
Discrete Phase

Battery-powered multi-rotor UAVs (Unmanned Aerial Vehicles) have been employed as chemical applicators in agriculture for small fields in China. Major challenges in spraying include reducing the influence of environmental factors and appropriate chemical use. Therefore, the objective of this research was to obtain the law of droplet drift and deposition by CFD (Computational Fluid Dynamics), a universal method to solve the fluid problem using a discretization mathematical method. DPM (Discrete Phase Model) was taken to simulate the motion of droplet particles since it is an appropriate way to simulate discrete phase in flow field and can track particle trajectory. The figure of deposition concentration and trace of droplet drift was obtained by controlling the variables of wind speed, pressure, and spray height. The droplet drifting models influenced by different factors were established by least square method after analysis of drift quantity to get the equation of drift quantity and safe distance. The relationship model, Yi(m), between three dependent variables, wind speed Xw(m s−1), pressure Xp(MPa) and spray height Xh(m), are listed as follows: The edge drift distance model was Y1 = 0.887Xw + 0.550Xp + 1.552Xh − 3.906 and the correlation coefficient (R2) was 0.837; the center drift distance model was Y2 = 0.167Xw + 0.085Xp + 0.308Xh − 0.667 and the correlation coefficient (R2) was 0.774; the overlap width model was Y3 = 0.692xw + 0.529xp + 1.469xh − 3.374 and the correlation coefficient (R2) was 0.795. For the three models, the coefficients of the three variables were all positive, indicating that the three factors were all positively correlated with edge drift distance, center drift distance, and overlap width. The results of this study can provide theoretical support for improving the spray quality of UAV and reducing the drift of droplets.

CFD Simulation of Water Flow Mixing With Discrete Phase in a Pump

2013 ◽  
Author(s):  
Mikhail P. Strongin
Keyword(s):  
Particle Distribution ◽  
Cfd Simulation ◽  
Liquid Mixture ◽  
Industrial Applications ◽  
Discrete Phase Model ◽  
Water Transportation ◽  
Flow Mixing ◽  
Discrete Phase ◽  
The Subject ◽  
Pump Inlet

The mixing process is very common in many industrial applications. In some cases, two or more liquids or discrete phase (DP) set on the pump inlet. Liquid mixture is often occurred in sanitation and agriculture applications and mixture of water with DP (such as sand) are met in the case of water transportation from natural sources (rivers, wells, etc.). DP distribution in the centrifugal pump is the subject of this study. Full pump geometry is considered, due to unsymmetrical nature of volute of the pump. Turbulence k-ε closure model and Lagrangian discrete phase model has been used for most simulations. It was found that smaller particles trap inside the pump for longer time than larger ones. The distribution of the bigger diameter particles on the outlet is more asymmetrical in comparison with particles of smaller diameter. Relatively large areas with very small particle concentrations can be observed. Particle distribution on the outlet for lighter particles demonstrates more uniformity.

CFD Study on must of Grapes Separation in a Hydrocyclone

2013 ◽  
Vol 837 ◽  
pp. 645-650
Author(s):  
Petru Cârlescu ◽  
Ioan Tenu ◽  
Marius Baetu ◽  
Radu Rosca
Keyword(s):  
Cfd Simulation ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Solid Particles ◽  
Advanced Degree ◽  
Separation And Purification ◽  
Discrete Phase Model ◽  
Flow Rates ◽  
Discrete Phase ◽  
Simulation And Experiment

Abstract. Hydrocyclones are increasingly used in the food industry for various separation and purification. In this paper, an optimization was made to design a hydrocyclone model using CFD (Computational Fluid Dynamics). CFD simulation is performed with FLUENT software by coupling the Reynolds Stress Model (RSM) for must of grapes flow with Discrete Phase Model (DPM) for solid particles trajectory. Coupling of discrete phase (particles) and continuous phase (must of grapes) in the mathematical model is set so that the continuous phase to influence discrete phase. Tracking particles traiectory in this hydrocyclone allows advanced degree is separation so obtained to the maximum particle size approaching the size of a yeast cell 10 μm, without separating them. Hydrocyclone dimensional designed simulation was performed and analyzed on an experimental pilot plant for three different must flow rates supply. Introduced particle flow rates simulation and experiment does not exceed 10% of the must flow rates. The degree of separation obtained is in agreement with experimental data.

CFD Simulation of COVID Aerosol Dispersion in Indoor Environments

2021 ◽  
Author(s):  
Mohammed Abushamleh ◽  
Ning Zhang
Keyword(s):  
Relative Humidity ◽  
Cfd Simulation ◽  
Medium Size ◽  
Indoor Environments ◽  
Discrete Phase Model ◽  
Discrete Phase ◽  
Computational Fluid Dynamics Simulations ◽  
Aerosol Dispersion ◽  
Dynamics Simulations ◽  
Simulation Time

Abstract Computational Fluid Dynamics simulations for the droplet’s dispersion generated by a cough in an indoor background, droplets trajectory, and evaporation time are predicted to be related to the droplet’s diameter and relative humidity. In general, medium-size droplets have higher axial penetration potential, and large droplets tend to settle on the ground due to gravity. Also, larger droplets take a longer time to evaporate. Smaller droplets tend to be suspended in the flow field with small penetration potential and tend to fade faster; smaller droplets < 20 μm evaporate completely before the simulation time reaches 0.75 sec. To study the effect of Relative Humidity (RH) on the evaporation rate, in particular, the present study offers three simulations, all with the same standard room conditions, only differ in relative humidity s 40%, 60%, and 90%. Another source of variability is the cough-expired volume. This study adopts existent experimental work to establish two cough flow rate profiles. The Lagrangian discrete phase model is adopted along with the species model to track and investigate the cough droplet dispersion and evaporation.

scholarly journals Modeling directional distributions of wind data in the United Arab Emirates at different elevations

2021 ◽  
Vol 14 (9) ◽  
Author(s):  
Aishah Al Yammahi ◽  
Prashanth R. Marpu ◽  
Taha B. M. J. Ouarda
Keyword(s):  
Wind Speed ◽  
United Arab Emirates ◽  
Wind Direction ◽  
Least Square Method ◽  
Least Square ◽  
Distribution Model ◽  
Long Term Effects ◽  
Energy Potential ◽  
Engineering Structures ◽  
Von Mises

AbstractModeling wind speed and direction are crucial in several applications such as the estimation of wind energy potential and the study of the long-term effects on engineering structures. While there have been several studies on modeling wind speed, studies on modeling wind direction are limited. In this work, we use a mixture of von Mises distributions to model wind direction. Finite mixtures of von Mises (FMVM) distributions are used to model wind directions at two sites in the United Arab Emirates. The parameters of the FMVM distribution are estimated using the least square method. The results of the research show that the FMVM is the best suited distribution model to fit wind direction at these two sites, compared to other distributions commonly used to model wind direction.

Simulation of Airflow and Fuel Spray Through an Axial Swirler for Gas Turbine Applications

2008 ◽  
Author(s):  
Joshua E. Kempenaar ◽  
Kim A. Shollenberger ◽  
Gareth W. Oskam
Keyword(s):  
Gas Turbine ◽  
Cfd Simulation ◽  
Cross Flow ◽  
Fuel Spray ◽  
Fuel Injector ◽  
Discrete Phase Model ◽  
Flow Area ◽  
Jet In Cross Flow ◽  
Discrete Phase ◽  
Break Up

A computational fluid dynamics (CFD) simulation of the effects of an upstream blockage on the fuel spray and airflow through an axial swirler in an experimental gas turbine fuel injector has been conducted. Blockage was varied by means of varying the inside diameter of a restriction upstream of the entrance to the axial swirler. Fuel is injected as a jet in cross-flow through fuel nozzles located in axial swirler vanes. Fuel spray was modeled in the commercial CFD code Fluent 6.3.26 using the Lagrangian approach with the built-in Discrete Phase Model (DPM). Results are given for the TAB, Wave, and KH-RT break-up models. Preliminary simulations with the TAB break-up model were performed for a simple axisymmetric jet and compared to experimental results before simulating the axial swirler geometry. The axial swirler simulations predict that spray dispersion decreases and droplet size increases as the flow area of the blocker ring increases.

scholarly journals THE LAST TIME ANALYSIS OF THE FOLLOWING FAMILY IN AL-QUR'AN PERSPECTIVE

2020 ◽  
Vol 2 (2) ◽  
pp. 18-20
Author(s):  
Rona Dwi Rahmah
Keyword(s):  
Natural Disasters ◽  
Correlation Coefficient ◽  
Real Data ◽  
Least Square Method ◽  
Least Square ◽  
Single Word ◽  
Time Analysis ◽  
The Earth ◽  
Relationship Of ◽  
The Relationship

Abstract. Earthquakes are natural disasters caused by shocks on the earth due to faults and the sudden movement of tectonic rocks that make up the earth's crust. This study of earthquakes will be interesting if explored further from the perspective of the Qur'an because in the Qur'an there are many verses that speak of earthquakes. As explained in the Qur'an Al-Zalzalah verses 1-8. On February 14 2016 to February 23 2016 aftershocks occurred in the Klagon Village Area, Saradan District, Madiun. To analyze when the end of aftershocks ends by using the Least Square Method and the relationship of frequency of aftershocks to times that include the Omori, Omogi 1, Omogi 2 and Utsu methods. The conclusion of this study is the Omogi 2 method which has obtained the correlation coefficient r = 0.195 from the correlation value -1 ≤ r ≤ 1, with the aftershocks ending on day 464 and from the comparison of aftershock frequency corresponding to the graph between the results data calculations with real data (actual data) namely the Omogi 2 method. And basically the term earthquake in the Qur'an can still be said not to make the verses interpreted as a single word containing the meaning of the earthquake as a brief explanation of aftershocks in the perspective of the Qur'an.

scholarly journals Simulation of un industrial waste treatment tank

2020 ◽  
Vol 9 (4) ◽  
pp. e180942542
Author(s):  
Elcio Fernando Pereira ◽  
Luiz Mário Nelson Gois
Keyword(s):  
Petrochemical Industry ◽  
Cfd Simulation ◽  
Waste Treatment ◽  
Discrete Phase Model ◽  
Depth Data ◽  
Treatment Tank ◽  
Computational Mesh ◽  
Discrete Phase ◽  
Particles Trajectories ◽  
Lagrange Approach

The objective of the present work was to evaluate the operation of an industrial sedimentation tank used in the separation of solid waste from the petrochemical industry. The depth data were obtained through a “interface float”, while the diameters and the positions of the particles through the CFD simulation. The computational fluid dynamics simulator (FLUENT 6.3.26) was used to perform a multiphase simulation using the Euler-Lagrange approach and was used to determine the particles trajectories and cotours of solids accumulated in the bottom of the tank. This allowed a better understanding of solids accumulation and improvement of the cleaning process. In the simulation of the tank a large computational mesh comprising 464,094 computational nodes was designed. The use of the Euler-Lagrange approach meant that a discrete phase model had to be established and the parameters of Rosin-Rammler solids distribtion model for the boundary conditions of the simulation had to be determined. 

Mathematical Modelling, Analysis of Novel Corona Disease, and Its Effect on the Human Being

2021 ◽  
Vol 11 (2) ◽  
pp. 17-29
Author(s):  
Kashfull Orra
Keyword(s):  
Mathematical Modelling ◽  
Correlation Coefficient ◽  
Graphical Representation ◽  
Function Analysis ◽  
Medical Practitioner ◽  
Least Square Method ◽  
Least Square ◽  
Quadratic Model ◽  
Quadratic Growth ◽  
Modelling Analysis

The present study is about the outbreak of novel Corona disease (COVID-19). The study proposes the mathematical modelling of COVID-19 disease as quadratic growth. Correlation coefficient associated with the characteristic of the modelling trend has been obtained by least square method using matlab function. Analysis of variance show the model proposed is significant. The study gave the information about the transmission of the disease and the prevention observed by the medical practitioner. The graphical representation has shown the outcome of the spread of the disease in India. This disease can be of respiratory type, pneumonia type, or asymptotic carrier type. The simulation result obtained is in accordance to the quadratic model fitted and can be used for the prediction of the growth. Results obtained on the basis of R2 were of approximately 97% in agreement. The only possibilities to avoid the spread of the disease is to monitor self-isolation, maintain cleanliness, improve immunity, and be protected.

CFD Simulation and Performance Analysis of CJD Burner for Intensified Flash Smelting Process

2012 ◽  
Author(s):  
Zhuo Chen ◽  
Peng Long ◽  
Zhiqiang Sun ◽  
Jun Zhou ◽  
Jiemin Zhou
Keyword(s):  
Cfd Simulation ◽  
Flash Smelting ◽  
Smelting Process ◽  
Flash Furnace ◽  
Discrete Phase Model ◽  
Reaction Shaft ◽  
Technical Problems ◽  
Dust Generation ◽  
Discrete Phase ◽  
And Performance

The flash smelting process has been widely acknowledged as a successful modern pyro-metallurgical technology because of its good production flexibility. In past decades, great efforts have been put on the equipment improvement in order to achieve a highly intensive and efficient flash smelting process. However, along with the increasing of the productivity and the intensification of the process, technical problems such as the un-smelted materials accumulated in the settler and the dust generation ratio going higher are found occurring more frequently than before. All these problems however indicate degeneration in the performance of the central jet distributor (CJD) burner. A study was then made on the combustion and reaction processes in the flash furnace equipped with a CJD burner. A steady-state turbulent model was developed and a discrete phase model was included to investigate the velocity and temperature changes of both the gaseous and particle phases in the reaction shaft. The deviation of the numerical model is estimated to be less than 6%. The simulation results reveal a serious delay in the ignition of concentrate particles after they are fed into the furnace. Minor modification was also made by CFD computation, attempting to improve the particle ignition speed, but it was found not so effective. The main reason for the decreased smelting efficiency is found to be the poor mixing between the gaseous and particle phases under the intensified condition. These appeal for a great improvement in the performance of the CJD burner.

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