Momentum Effects on the Spray Drop Size, Calculated from the Integral Form of the Conservation Equations

2012 ◽  
Vol 184 (3) ◽  
pp. 434-443 ◽  
Author(s):  
T.-W. Lee ◽  
J. Y. Lee ◽  
Y. H. Do
Keyword(s):  
Drop Size ◽  
Integral Form ◽  
Conservation Equations

Determination of the Drop Size During Air-Blast Atomization

2019 ◽  
Vol 141 (12) ◽  
Author(s):  
T.-W. Lee ◽  
J. E. Park
Keyword(s):  
Kinetic Energy ◽  
Viscous Dissipation ◽  
High Speed ◽  
Drop Size ◽  
Integral Form ◽  
Initial Kinetic Energy ◽  
Air Blast ◽  
Dissipation Term ◽  
Wide Range ◽  
Drop Size Distributions

We have used the integral form of the conservation equations, to find a cubic formula for the drop size during in liquid sprays in coflow of air (air-blast atomization). Similar to our previous work, the energy balance dictates that the initial kinetic energy of the gas and injected liquid will be distributed into the final surface tension energy, kinetic energy of the gas and droplets, and viscous dissipation. Using this approach, the drop size can be determined based on the basic injection and fluid parameters for “air-blast” atomization, where the injected liquid is atomized by high-speed coflow of air. The viscous dissipation term is estimated using appropriate velocity and length scales of liquid–air coflow breakup. The mass and energy balances for the spray flows render to an expression that relates the drop size to all of the relevant parameters, including the gas- and liquid-phase velocities and fluid properties. The results agree well with experimental data and correlations for the drop size. The solution also provides for drop size–velocity cross-correlation, leading to computed drop size distributions based on the gas-phase velocity distribution. This approach can be used in the estimation of the drop size for practical sprays and also as a primary atomization module in computational simulations of air-blast atomization over a wide range of injection and fluid conditions, the only caveat being that a parameter to account for the viscous dissipation needs to be calibrated with a minimal set of observational data.

Computational Simulations of Liquid Sprays in Crossflows with an Algorithmic Module for Primary Atomization

2020 ◽  
Author(s):  
Taewoo Lee ◽  
Benjamin Greenlee ◽  
Jung Eun Park ◽  
Hana Bellerova ◽  
Miroslav Raudensky
Keyword(s):  
Drop Size ◽  
Initial Conditions ◽  
Energy State ◽  
Integral Form ◽  
Computational Procedure ◽  
Fluid Simulation ◽  
Liquid Jets ◽  
Quadratic Formula ◽  
Initial Drop ◽  
Drop Size Distributions

Abstract For simulations of liquid jets in crossflows, the primary atomization can be treated with the quadratic formula, which has been derived from integral form of conservation equations of mass and energy in our previous work. This formula relates the drop size with the local kinetic energy state, so that local velocity data from the volume-of-fluid simulation prior to the atomization can be used to determine the initial drop size. This initial drop size, along with appropriately sampled local gas velocities, are used as the initial conditions in the dispersed-phase simulation. This procedure has been performed on a coarse-grid platform, with good validation and comparison with available experimental data at realistic Reynolds and Weber numbers, representative of gas-turbine combustor flows. The computational procedure produces all the relevant spray characteristics: spatial distributions of drop size, velocities, and volume fluxes, along with global drop size distributions. The primary atomization module is based on the conservation principles, and is generalizable and implementable to any combustor geometries for accurate and efficient computations of spray flows.

Computational Protocol for Spray Flow Simulations Including Primary Atomization

2020 ◽  
Vol 143 (3) ◽  
Author(s):  
T.-W. Lee ◽  
B. Greenlee ◽  
J. E. Park
Keyword(s):  
Drop Size ◽  
Integral Form ◽  
Quadratic Formula ◽  
Flow Simulations ◽  
Initial Drop ◽  
Lagrangian Tracking ◽  
Droplet Liquid ◽  
Computational Protocol ◽  
Spray Flows

Abstract Primary atomization is the key element in spray flow simulations. We have, in our previous work, used and validated the integral form of the conservation equations, leading to the “quadratic formula” for determination of the drop size during spray atomization in various geometry. A computational protocol has been developed where this formulation is adapted to existing computational frameworks for continuous and dispersed (droplet) liquid phase, for simulations of pressure-atomized sprays with and without swirl. In principle, this protocol can be applied to any spray geometry, with appropriate modifications in the atomization criterion. The preatomization continuous liquid motion (e.g., liquid column or sheet) is computed using volume-of-fluid (VOF) or similar methods, then the velocity data from this computation is input to the quadratic formula for determination of the local drop size. This initial drop size, along with the local liquid velocities from VOF, is then used in a Lagrangian tracking algorithm for the postatomization dispersed droplet calculations. This protocol can be implemented on coarse-grid, time-averaged simulations of spray flows, and produces convincing results when compared with experimental data for pressure-atomized sprays with and without swirl. This approach is general, and can be adapted in any spray geometries for complete and efficient computations of spray flows.

ДОСВІД У ДИСКУСІЙНОМУ ПОЛІ ПОЗИЦІЮВАННЯ КАТЕГОРІЇ "ТВОРЧИЙ ПОТЕНЦІАЛ"

1970 ◽  
Vol 6 (1) ◽  
pp. 62-71
Author(s):  
Лариса Міщиха
Keyword(s):  
Coming Out ◽  
Motion Vector ◽  
Integral Form ◽  
Phenomenological Approach ◽  
Humanistic Psychology ◽  
Creative Potential ◽  
Form Of Life ◽  
Conceptual Background ◽  
Creative Experience ◽  
The One

У статті зроблено спробу проаналізувати феномен "досвід" у форматі дослідження творчого потенціалу особистості. Теоретико-методологічними засадами заявленої вище проблеми стали концептуальні засади гуманістичної психології, феноменологічного підходу. Досвід, як вагома складова творчого потенціалу особистості, розглядається у співвідношенні таких провідних тенденцій, як стереотипність та оригінальність. Наголошується, що досвід, з одного боку, може сприяти все більшій алгоритмізації та стереотипізації, консерватизму у розв’язанні нових задач, що безумовно перешкоджає творчості. З іншого боку, в осіб з високим творчим потенціалом він стає інтегрованою формою життєтворчості, де в структурі старих знань завжди знайдеться місце новим знанням як привнесених "ззовні", так і знанням, що їх отримує автор через власні ініціації, пошук, накреслюючи власноруч вектор руху. Звідси він отримує "побічний продукт" творчої діяльності – саморозвиток. Відтак творчий досвід трактується як такий, що містить у собі акумуляцію та інтеграцію усіх прижиттєвих творчих напрацювань особистості, готовність її до творчої діяльності та безперервної освіти. Суб’єкт творчої діяльності залишається відкритим новому досвіду, сповнений готовності до нового пізнання, творчих пошуків. In the article there was an attempt to analyze the phenomenon "experience" in the form of investigating a person’s creative potential. The theoretic methodological background of the performed above problem is conceptual background of humanistic psychology and phenomenological approach. Experience as an essential part of a person’s creative potential is regarded in relation to such leading trends as stereotype and originality. On the one hand, the experience is emphasized to be able to promote the model of algorithm and stereotype, conservatism in solving new tasks that is certain to inhibit creativity. On the other hand, personalities with high creative potential have an experience that is becoming an integral form of life work where in the structure of old knowledge you can always find a place for both new ones coming out "from inside" and the ones the author takes due to his own initiation and search. In this way he sketches motion vector and gets the "by-product" of his creativity, it means self-development. Hence, creative experience is interpreted as the one to absorb accumulation and integration of all creative experience in a person’s life; also his/her readiness to creativity and continuing education. The subject of creativity remains opened to a new experience that is fully ready for a new cognition and creativity.

COMPARISON OF DROP SIZE DATA FROM GROUND AND AERIAL APPLICATION NOZZLES AT THREE TESTING LABORATORIES

2014 ◽  
Vol 24 (2) ◽  
pp. 181-192 ◽  
Author(s):  
Bradley K. Fritz ◽  
W. Clint Hoffmann ◽  
Greg R. Kruger ◽  
Ryan S. Henry ◽  
Andrew Hewitt ◽  
...  
Keyword(s):  
Drop Size ◽  
Aerial Application ◽  
Testing Laboratories ◽  
Size Data
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