TY - JOUR

T1 - Features of the Flow of a Model Liquid Into a Medium With a Variable Degree of Rarefaction

AU - Yaskin, A. S.

AU - Zarvin, A. E.

AU - Dubrovin, K. A.

AU - Kalyada, V. V.

N1 - Funding Information: The work was performed using the shared equipment center "Applied physics" of the NSU Physics Department with the financial support from the Ministry of Science and Higher Education of the Russian Federation (project number FSUS-2020-0039) and RFBR (grant number 20-01-00332\20). Publisher Copyright: © 2022 American Society of Mechanical Engineers (ASME). All rights reserved.

PY - 2022/7/1

Y1 - 2022/7/1

N2 - Experimental results of observing ethanol microjets expiring into a highly rarefied medium (vacuum) through a nozzle are presented. The study of the process was carried out both at the horizontal and vertical liquid stream from the source compared to the direction of gravity The residual background gas pressure in the vacuum chamber was maintained at a level much lower than the saturated vapor pressure of the working fluid at a given outlet temperature. The possibility of modeling complex processes of microfluids expiring into a medium with a given rarefied atmosphere on a compact vacuum gas-dynamic stand is shown. It is established that the long-term flow from a thin capillary or a small-diameter hole into a vacuum or a highly rarefied gas medium differs significantly from the well-studied flow modes into a dense gas medium, as well as from the pulsed flow modes into a vacuum. The paper describes the main features of the flow and the conditions for the occurrence of instability. It is shown that the long-term flow of a liquid microjet in a vacuum has a high degree of surface instability, with a large number of sudden changes in the direction, structure, and observed density. An explanation of the reasons for the destruction of the microjet (due to the combination of capillary instability and intense evaporation of superheated liquid from the surface of the jet) is proposed. The formation of surface gas caverns causing explosive destruction of the microjet with the release of vapor-liquid droplets is established.

AB - Experimental results of observing ethanol microjets expiring into a highly rarefied medium (vacuum) through a nozzle are presented. The study of the process was carried out both at the horizontal and vertical liquid stream from the source compared to the direction of gravity The residual background gas pressure in the vacuum chamber was maintained at a level much lower than the saturated vapor pressure of the working fluid at a given outlet temperature. The possibility of modeling complex processes of microfluids expiring into a medium with a given rarefied atmosphere on a compact vacuum gas-dynamic stand is shown. It is established that the long-term flow from a thin capillary or a small-diameter hole into a vacuum or a highly rarefied gas medium differs significantly from the well-studied flow modes into a dense gas medium, as well as from the pulsed flow modes into a vacuum. The paper describes the main features of the flow and the conditions for the occurrence of instability. It is shown that the long-term flow of a liquid microjet in a vacuum has a high degree of surface instability, with a large number of sudden changes in the direction, structure, and observed density. An explanation of the reasons for the destruction of the microjet (due to the combination of capillary instability and intense evaporation of superheated liquid from the surface of the jet) is proposed. The formation of surface gas caverns causing explosive destruction of the microjet with the release of vapor-liquid droplets is established.

KW - ethanol

KW - liquid micro-jet

KW - modeling of vacuum conditions

KW - saturated flow

KW - surface instability

UR - http://www.scopus.com/inward/record.url?scp=85125068126&partnerID=8YFLogxK

U2 - 10.1115/1.4053372

DO - 10.1115/1.4053372

M3 - Article

AN - SCOPUS:85125068126

VL - 144

JO - Journal of Fluids Engineering, Transactions of the ASME

JF - Journal of Fluids Engineering, Transactions of the ASME

SN - 0098-2202

IS - 7

M1 - 071204

ER -