The Use of Computational Fluid Dynamic Code for Modelling Spray from a Mistblower

Weiner, K.-L.; Parkin, C.S.

doi:10.1006/jaer.1993.1052

Cited by 19 publications

(8 citation statements)

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“…Wilson & Shaw, 1977;Katul, 2004). The two equations k. model is the most popular in engineering applications and was used in several spray models (Weiner & Parkin, 1993;Zhu, Reichard, Fox, Brazee, & Ozkan, 1994;Xu et al, 1998;Brown & Sidhamed, 2001). In this work, the Reynolds averaged equations together with a k. model were used.…”

Section: Air Flow Modelmentioning

confidence: 98%

A Lagrangian model for spray behaviour within vine canopies

Silva

Sinfort²,

Tinet³

et al. 2006

Journal of Aerosol Science

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This work concerns the numerical prediction of pesticide deposits on vine by air assisted sprayers. This numerical model consists in two different parts: the air flow characteristics were obtained through a Navier-Stokes solver in which additional terms have been introduced in order to account for the modification of the flow by the vine foliage. The theoretical form of these terms was derived through an averaging procedure. As a result, the canopy effect was modelled by introducing momentum and turbulence source terms in the Navier-Stokes equations. The constants were identified thanks to experimental data obtained by direct measurements of the air flow speeds through an artificial canopy. The second part of the model consists in simulating the droplet cloud by means of a lagrangian stochastic model. The average motion of the droplets was computed through the use of lagrangian coordinates and the turbulence effect on the droplets was interpreted in term of statistical properties of the droplet cloud. The tractor displacements were accounted for through unsteady boundary conditions. Once the size and the droplets cloud locations have been determined, the deposit was predicted for a vine row of one meter length using an efficiency coefficient obtained from simulations. Thanks to this approach we were able to quantify the effect of air turbulence on droplet deposition / Ce travail concerne la prédiction numérique de dépôts dans la vigne de pesticides pulvérisés avec assistance d'air. Le modèle numérique comprend deux parties : les caractétistiques du flux d'air sont obtenues à partir de la résolution des équations de Navier-Stokes dans lesquelles des termes additionnels ont été introduits pour prendre en compte les modifications du flux dues au feuillage. L'effet de la végétation est modélisé en introduisant des termes source de quantité de mouvement et de turbulence dans les équations de Navier Stokes. Les constantes ont été identifiées grâce à des données expérimentales obtenues par des mesures directes des vitesses d'air dans une végétation artificielle. la deuxième partie du modèle représente le nuage de goutteletters à l'aide d'une représentation Lagrangienne stochastique. Le mouvement moyen des gouttes est calculé à partir de leurs coordonnées Lagrangiennes et l'effet de la turbulence est pris en compte dans les propriétés statistiques du nuage; Les déplacements du tracteur sont pris en compte par des conditions aux limites transitoires. Une fois que la taille et la position du nuage de gouttelettes est déterminé, le dépot est calculé sur un mètre de rang de vigne en utilisant un coefficient d'efficacité calculé à l'aide de simulations. Grâce à cette approche, on peut prédire les effets de la turbulence sur le dépôt des goutte

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Section: Air Flow Modelmentioning

confidence: 98%

A Lagrangian model for spray behaviour within vine canopies

Silva

Sinfort²,

Tinet³

et al. 2006

Journal of Aerosol Science

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“…A similar approach has been implemented to study the spray coating and spray forming processes in Refs. [107,30,32]. However, only the droplet spray characteristics were investigated and the deposition and film formation on the substrate were not considered in their studies.…”

Section: Dielectric Spray Modelmentioning

confidence: 99%

Atomized Dielectric Spray-Based Electric Discharge Machining (Spray-EDM) for Sustainable Manufacturing

Pattabhiraman

Marla

Kapoor

2015

Volume 1: Processing

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Electrical Discharge Machining is a non-traditional machining process that is widely used in the tool and die-making industry, automotive, and aerospace industries due to its ability to produce complex three-dimensional geometries with good accuracy and surface finish. Despite the aforementioned advantages, the consumption of a large quantity of dielectric (especially hydrocarbon oils) poses a significant health and environmental hazard including respiratory and skin irritation issues. Further, the disposal of waste dielectric that contains a significant amount of metal particulates poses safety concerns. In order to comply with environmental safety standards, extensive filtration and treatment systems capable of handling huge amounts of dielectric waste need to be set up for their safe disposal.This leads to an increased energy consumption and hence higher operating cost for the machining process. Thus, there is a need to reduce the consumption of oil-based dielectrics without compromising their superior machining performance.Several techniques including dry and near-dry EDM have been developed to reduce the consumption of dielectrics. However, they have poor debris flushing capability. This research seeks to develop a technique that minimizes the consumption of dielectrics and also improves the flushing of debris from the inter-electrode gap.A novel method of using atomized dielectric spray in EDM (Spray-EDM) to reduce the consumption of dielectric is developed in this study. The atomized dielectric droplets form a moving dielectric film up on impinging the work surface that penetrates the inter-electrode gap and acts as a single-phase dielectric medium between the electrodes. It also effectively removes the debris particles from the discharge zone. Single-discharge EDM experiments are performed using ii three different dielectric supply methods, viz., conventional Wet-EDM (electrodes submerged in dielectric medium), Dry-EDM and Spray-EDM in order to compare the processes based on material removal, tool electrode wear and flushing of debris from the inter-electrode gap across a range of discharge energies. It is observed that Spray-EDM produces higher material removal compared to the other two methods for all combinations of discharge parameters used in the study.The tool electrode wear using atomized dielectric is significantly better than Dry-EDM and comparable to that observed in Wet-EDM. The percentage of debris particles deposited within a distance of 100 µm from the center of EDM crater is also significantly reduced using the Spray-EDM technique. iv

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“…In some applications, spray droplets injected from arrays of nozzles are carried within orientated air-jet streams. The strong air-jets carry droplets and reduce the flight time of droplets, which can reduce the interferences of wind and weather conditions and increase spray deposition within the crop canopy [11]. However, the use of air-jets can cause excessive environmental contamination by spray drift and ground deposition if the air streams are poorly matched to the intended crops [10].…”

Section: Introductionmentioning

confidence: 99%

“…One of the most recent fluid-mechanical approaches is a computational fluid dynamics (CFD) simulation, which solves complex airflow and turbulence patterns by solving the Navier-Stokes equations. Although the above analytical methods are available to describe some feature of turbulent air jets, they are mostly suitable for studying isolated free jets [11].…”

Section: Introductionmentioning

confidence: 99%

Fluid Dynamic Approaches for Prediction of Spray Drift from Ground Pesticide Applications: A Review

et al. 2021

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Spray drifts have been studied by mathematical models and computer simulations as an essential complement to lab and field tests, among which are fluid dynamic approaches that help to understand the transport of spray droplets in a turbulent atmosphere and their potential impacts to the environment. From earlier fluid mechanical models to highly computational models, scientific advancement has led to a more realistic prediction of spray drift, but the current literature lacks reviews showing the trends and limitations of the existing approaches. This paper is to review the literature on fluid-mechanical-based modelling of spray drift resulting from ground spray applications. Consequently, it provides comprehensive understanding of the transition and development of fluid dynamic approaches and the future directions in this research field.

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The Use of Computational Fluid Dynamic Code for Modelling Spray from a Mistblower

Cited by 19 publications

References 0 publications

A Lagrangian model for spray behaviour within vine canopies

A Lagrangian model for spray behaviour within vine canopies

Atomized Dielectric Spray-Based Electric Discharge Machining (Spray-EDM) for Sustainable Manufacturing

Fluid Dynamic Approaches for Prediction of Spray Drift from Ground Pesticide Applications: A Review

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