A Combined Eulerian and Lagrangian Method for Prediction of Evaporating Sprays

Burger, M.; Klose, Göran; Rottenkolber, Gregor; Schmehl, Roland; Giebert, Dietmar; Schäfer, O.; Koch, R.; Wittig, Sigmar

doi:10.1115/2001-gt-0047

Cited by 12 publications

(8 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The combination of an ultrasonic atomizer and a nozzle system to focus the fluid droplets prior to deposition is unique to ACF systems and necessitates the development of a new computational model Figure 2.64: Comparison of droplet velocity using different approaches [34] Ring pattern Dot pattern Figure 2.65: Spray patterns and film thickness profiles [35] to understand and improve the design of spray system.…”

Section: 60) the Droplet Trajectoriesmentioning

confidence: 99%

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

Pattabhiraman

Marla

Kapoor

2015

Volume 1: Processing

View full text Add to dashboard Cite

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

show abstract

Section: 60) the Droplet Trajectoriesmentioning

confidence: 99%

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

Pattabhiraman

Marla

Kapoor

2015

Volume 1: Processing

View full text Add to dashboard Cite

show abstract

“…8 recorded 2 ms after injection start. A detailed description of droplet initial conditions which have been used in the present study is available [2]. …”

Section: Droplet Starting Conditionsmentioning

confidence: 99%

“…As the surface temperature of the inlet valve is exceeding 100 AE C (373 K) for these operating conditions [14], hot surfaces with wall films are approximated as dry walls in the present study assuming rapid evaporation of the deposited liquid fuel. The accuracy of the numerical codes in terms of gas/droplet velocity, droplet number density and fuel vapor concentration has been investigated previously [2] [19].…”

Section: Introductionmentioning

confidence: 99%

Predictions of Transient Fuel Spray Phenomena in the Intake Port of a Si-Engine

Burger¹,

Schmehl²,

Gorse³

et al. 2002

SAE Technical Paper Series

Self Cite

View full text Add to dashboard Cite

The present study addresses the numerical prediction of the two-phase flow in the intake port of a SI-engine. Particular emphasis is put on transient phenomena, as well as secondary effects, such as droplet breakup and droplet wall interaction. These phenomena have a significant influence on the fuel air mixture characteristics and cannot be neglected in the numerical prediction. The numerical methodology, presented in this paper, is based on a 3D body-fitted Finite Volume discretization of the gas flow field and a Lagrangian particle tracking algorithm of the disperse fuel phase. The Unsteady Reynolds Averaged Navier-Stokes equations (URANS) are solved by a time-implicit three level scheme. In the Lagrangian particle tracking algorithm, the spray is modeled by superposition of a large number of droplet trajectories. Two advanced numerically effective models are presented for the prediction of droplet breakup and droplet wall interaction. Special emphasis is put on the correct reproduction of the droplet statistics. In the present study the fuel injection and spray preparation process within the intake port of a SI-engine is investigated. Spray preparation is dominated by atomization processes like droplet breakup and wall interaction which predominantly take place at the valve seat. In order to find the principal characteristics of fuel preparation in a SI-engine, a parametric study has been carried out focusing on the influence of the gap sizes of the intake valve which strongly affects the complete fuel preparation process. The study is concluded by an analysis of qualitative and quantitative results of the predicted flow field.

show abstract

“…Air relative humidity, a parameter which is indeed relevant to the whole phenomenological picture, was instead not considered here due to technical limits, because the solver implemented within STAR CCM+ could not tackle that issue due to a water-air interface modelling limit: this, anyway, does not affect the generality of the present study as the "classical" parametric approach adopted (one variable varying at a time for every simulation; all the others kept as constants) assures the independence of any parametric result from another. Droplet evaporation was described by means of an Eulerian-Lagrangian approach, typical of this kind of processes [44,45], even if fully Lagrangian approaches [46] and other approaches [47] are also reported in literature. A range of twenty cases study was faced, five for each analysis parameter.…”

Section: Introductionmentioning

confidence: 99%

Computational Fluid Dynamics (CFD) Picture of Water Droplet Evaporation in Air

Lorenzini¹,

Conti²,

Wrachien

2012

Irrigat Drain Sys Engg

View full text Add to dashboard Cite

The study of droplet evaporation is applied to many and varied fields: the present approach is oriented to sprinkler irrigation. This paper examines a parametric study on the evaporation in air of a single droplet, with the aim of highlighting the influence of each parameter alone on the evaporative process. Four parameters are investigated: air temperature, droplet initial velocity, droplet initial diameter, diffusion coefficient of vapour in air. Droplet evaporation is studied through numerical-CFD simulation employing STAR-CCM+ version 5.04.012 software, which treats the evaporative phenomenon hypothesizing quasi-steady conditions, given the interface low liquid-gas vapour concentration gradients. The results are provided as time-and space-dependent in-percentage evaporation rates, the latter ones after defining a specific distance, from the injection point, to be covered. Apart from a qualitatively predictable effect of air temperature and diffusion coefficient of vapour in air, droplet initial velocity and above all droplet initial diameter prove not at all to be negligible when managing an irrigation process, the latter being inversely proportional to droplet mass evaporation. These results prove that droplet evaporation is a complicate fluid dynamic effect and cannot be simply regarded as a diffusive process. The final discussion provides some practical remarks useful to irrigation operators. Ir ri g ation & D r a in ag e Sys te m s E ng ineer in g

show abstract

A Combined Eulerian and Lagrangian Method for Prediction of Evaporating Sprays

Cited by 12 publications

References 0 publications

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

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

Predictions of Transient Fuel Spray Phenomena in the Intake Port of a Si-Engine

Computational Fluid Dynamics (CFD) Picture of Water Droplet Evaporation in Air

Contact Info

Product

Resources

About