An experimental investigation of a liquid jet expelled into a vacuum.

Anderson, Ray G.; Mikatarian, Ron

doi:10.2514/3.28432

Cited by 15 publications

(5 citation statements)

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“…Considering only pipe jets, 4 studies were neglected because the QoIs were not measured at all [8,11,14,27]. These studies tended to be old and were often qualitative (e.g.…”

Section: Not Measuring the Most Typical Quantity Of Interestmentioning

confidence: 99%

Improving the validation of turbulent jet breakup models

Trettel¹

2019

Preprint

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Understanding the physics of the breakup of turbulent liquid jets is important for a variety of applications including engine sprays, fire suppression systems, and water jet cutting. Models of turbulent jet breakup allow predictions of quantities of interest like the droplet size distribution and breakup length of the jet. These models are compared against experimental data in a process called validation. If the model predictions are within the experimental uncertainty, then the model is "validated" and believed to be accurate, and possibly can explain the physics. Uncertainty quantification is necessary for model validation. While unfortunately relatively few experimental studies quantify uncertainty, that is not the most pressing validation issue in turbulent jet breakup. I detail 3 additional problems that can make the apparent validation of a model actually an illusion, regardless of how well the model appears to match the data. These problems include: 1. important variables being omitted or guessed in experiments and models, 2. confounding between independent variables, that is, two variables changing simultaneously, making determining cause and effect impossible, and 3. testing only combinations of submodels and not each submodel in isolation. To avoid these problems and others, I developed validation guidelines that are detailed in this work. Following these guidelines, I compiled a large experimental database. Only 28 out of 47 experimental studies considered met my data quality guidelines. Only 18 studies had quantified uncertainty, and only 3 studies had substantial variation in the turbulence intensity.

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“…Considering only pipe jets, 4 studies were neglected because the QoIs were not measured at all [8,11,14,27]. These studies tended to be old and were often qualitative (e.g.…”

Section: Not Measuring the Most Typical Quantity Of Interestmentioning

confidence: 99%

Improving the validation of turbulent jet breakup models

Trettel¹

2019

Preprint

View full text Add to dashboard Cite

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“…Что касается состояния вопроса по тематике статьи, нам не удалось найти публикаций по истечению пристенных пленок жидкостей со спутным газовым потоком в вакуум. Имеющиеся публикации, в частности [2][3][4], посвящены истечению жидкостей (в основном воды) из трубок различного диаметра и связаны с космической тематикой.…”

Section: Introductionunclassified

Experimental Study of Near-Wall Liquid Film Outflow with Co-Current Gas Flow from Nozzle into Vacuum. 2. Flow Structure behind Nozzle

Vyazov¹,

Prikhodko²,

Yarygin³

et al. 2019

PhChGD

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Outflow of a near-wall liquid film with co-current gas flow from a nozzle (cylindrical channel) into vacuum is studied experimentally. Special features of near-wall liquid films ejection into vacuum are established with the help of the developed measurement techniques (droplet phase flow structure visualization with ordinary and laser illumination, deposition of droplets on paper substrates, spectrophotometry): turn of the film in the opposite direction at the nozzle lip and its rise along the outer surface of the nozzle against gravity, cooling due to evaporation, disintegration into droplets with the formation of the spatial flow structure, which includes two typical areas: central and peripheral. The temperature of the liquid film formed on the outer surface of the nozzle is measured. It is shown that the film is cooled down to a temperature at which the pressure of liquid saturated vapors becomes equal to the pressure in the vacuum chamber. The distribution functions of droplets by size, direction of fly, and velocity in the peripheral area of the flow are obtained.

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“…Одна из особенностей рассматриваемой задачи состоит в том, что при попадании в вакуум жидкость становится мгновенно «перегретой», что приводит к её взрывообразному распаду на капли. В настоящее время в литературе имеются публикации по истечению воды в вакуум [1][2][3]. Практически все они связаны с космическими приложениями и посвящены сбросу воды с орбитальных станций через трубки разного диаметра.…”

Section: Introductionunclassified

Experimental study of near-wall liquid film outflow with co-current gas flow from nozzle into vacuum. 1. Interaction inside nozzle

Vyazov¹,

Prikhodko²,

Yarygin³

2018

PhChGD

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Interaction of co-current gas flow with near-wall liquid film inside a nozzle (cylindrical channel) under ejection into vacuum is studied experimentally. Local parameters of near-wall films of ethanol, water and their mixtures under interaction with co-current air flow are measured with the help of capacity-type probes. It is shown that under conditions of experiments carried out co-current flow exert strong dynamic impact on near-wall liquid film, leading to intensive wave formation, detachment of droplet and their dispersal by co-current flow. It is found that the amount of liquid entrained from boundary surface can reach over 50 % from the initial flow rate of liquid. Flow structure of gas-droplet jet arising under ejection into vacuum is visualized with the help of laser illumination. Appearance of droplets backflows (at angles over 90 with respect to nozzle axis) is shown. Temperature of the film formed on the nozzle external surface is measured. It is shown that the film of liquid is cooled down to the temperature at which its saturated vapor pressure becomes equal to pressure in vacuum chamber.

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An experimental investigation of a liquid jet expelled into a vacuum.

Cited by 15 publications

References 0 publications

Improving the validation of turbulent jet breakup models

Improving the validation of turbulent jet breakup models

Experimental Study of Near-Wall Liquid Film Outflow with Co-Current Gas Flow from Nozzle into Vacuum. 2. Flow Structure behind Nozzle

Experimental study of near-wall liquid film outflow with co-current gas flow from nozzle into vacuum. 1. Interaction inside nozzle

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