EXP 1-1: Difference between revisions

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! <br />Description
! <br />Description
|-
|-
| <br />A
| <br /><math>A</math>
| <br />cross-section
| <br />Cross-section
|-
|-
| <br />AT
| <br /><math>AT</math>
| <br />arrival time to the measurement volume
| <br />Arrival time to the measurement volume
|-
|-
| <br />Bo
| <br /><math>Bo</math>
| <br />Bond number
| <br />Bond number
|-
|-
| <br />c
| <br /><math>c</math>
| <br />droplet concentration
| <br />Droplet concentration
|-
|-
| <br /><math>C_D</math>
| <br /><math>C_D</math>
| <br />discharge coefficient
| <br />Discharge coefficient
|-
|-
| <br />D
| <br /><math>D</math>
| <br />mean droplet diameter
| <br />Mean droplet diameter
|-
|-
| <br />d
| <br /><math>d</math>
| <br />diameter
| <br />Diameter
|-
|-
| <br /><math>D_{10}</math>
| <br /><math>D_{10}</math>
| <br />arithmetic mean diameter
| <br />Arithmetic mean diameter
|-
|-
| <br /><math>D_{20}</math>
| <br /><math>D_{20}</math>
| <br />surface mean diameter
| <br />Surface mean diameter
|-
|-
| <br /><math>D_{32}</math>
| <br /><math>D_{32}</math>
| <br />Sauter mean diameter
| <br />Sauter mean diameter
|-
|-
| <br />F
| <br /><math>F</math>
| <br />force acting on a liquid element
| <br />Force acting on a liquid element
|-
|-
| <br />Fr
| <br /><math>Fr</math>
| <br />Froude number
| <br />Froude number
|-
|-
| <br />G
| <br /><math>G</math>
| <br />gravitational acceleration
| <br />Gravitational acceleration
|-
|-
| <br />K
| <br /><math>K</math>
| <br />nozzle dimension constant
| <br />Nozzle dimension constant
|-
|-
| <br />L
| <br /><math>L</math>
| <br />characteristic distance
| <br />Characteristic distance
|-
|-
| <br /><math>l_{b}</math>
| <br /><math>l_{b}</math>
| <br />break-up distance
| <br />Break-up distance
|-
|-
| <br />LDA1
| <br /><math>LDA1</math>
| <br />velocity in Z-direction
| <br />Velocity in Z-direction
|-
|-
| <br />LDA4
| <br /><math>LDA4</math>
| <br />velocity in Y-direction
| <br />Velocity in Y-direction
|-
|-
| <br />n
| <br /><math>n</math>
| <br />wave number
| <br />Wave number
|-
|-
| <br />Oh
| <br /><math>Oh</math>
| <br />Ohnesorge number
| <br />Ohnesorge number
|-
|-
| <br />p
| <br /><math>p</math>
| <br />pressure
| <br />Pressure
|-
|-
| <br />Q
| <br /><math>Q</math>
| <br />flow rate
| <br />Flow rate
|-
|-
| <br />q
| <br /><math>q</math>
| <br />liquid-to-air momentum ratio
| <br />Liquid-to-air momentum ratio
|-
|-
| <br />r
| <br /><math>r</math>
| <br />radius
| <br />Radius
|-
|-
| <br />Re
| <br /><math>Re</math>
| <br />Reynolds number
| <br />Reynolds number
|-
|-
| <br />S
| <br /><math>S</math>
| <br />swirl number
| <br />Swirl number
|-
|-
| <br />Stk
| <br /><math>Stk</math>
| <br />Stokes number
| <br />Stokes number
|-
|-
| <br />SCA
| <br /><math>SCA</math>
| <br />spray cone angle
| <br />Spray cone angle
|-
|-
| <br />t
| <br /><math>t</math>
| <br />time
| <br />Time
|-
|-
| <br />TT
| <br /><math>TT</math>
| <br />transit time  through the measurement volume
| <br />Transit time  through the measurement volume
|-
|-
| <br />Tu
| <br /><math>Tu</math>
| <br />turbulence intensity
| <br />Turbulence intensity
|-
|-
| <br />u
| <br /><math>u</math>
| <br />velocity
| <br />Velocity
|-
|-
| <br />U12
| <br /><math>U12</math>
| <br />phase shift  between photomultipliers 1 and 2
| <br />Phase shift  between photomultipliers 1 and 2
|-
|-
| <br />U13
| <br /><math>U13</math>
| <br />phase shift  between photomultipliers 1 and 3
| <br />Phase shift  between photomultipliers 1 and 3
|-
|-
| <br />w
| <br /><math>w</math>
| <br />swirl component of the velocity
| <br />Swirl component of the velocity
|-
|-
| <br />We
| <br /><math>We</math>
| <br />Weber number
| <br />Weber number
|-
|-
| <br />X,  Y, Z
| <br /><math>X,  Y, Z</math>
| <br />Cartesian coordinates
| <br />Cartesian coordinates
|-
|-
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|-
|-
| <br /><math>\Delta v </math>
| <br /><math>\Delta v </math>
| <br />difference between the gas and droplet velocity
| <br />Difference between the gas and droplet velocity
|-
|-
| <br /><math>\eta_{n}</math>
| <br /><math>\eta_{n}</math>
| <br />nozzle efficiency
| <br />Nozzle efficiency
|-
|-
| <br /><math>\mu</math>
| <br /><math>\mu</math>
| <br />dynamic viscosity
| <br />Dynamic viscosity
|-
|-
| <br />ρ
| <br /><math>\rho</math>
| <br />liquid density
| <br />Liquid density
|-
|-
| <br />σ
| <br /><math>\sigma</math>
| <br />surface tension
| <br />Surface tension
|-
|-
| <br />
| <br />
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| style="font-weight:normal;" | <br />
| style="font-weight:normal;" | <br />
|-
|-
| <br />a
| <br /><math>a</math>
| <br />aerodynamic
| <br />Aerodynamic
|-
|-
| <br />ac
| <br /><math>ac</math>
| <br />air core
| <br />Air core
|-
|-
| <br />c
| <br /><math>c</math>
| <br />swirl chamber
| <br />Swirl chamber
|-
|-
| <br />cf
| <br /><math>cf</math>
| <br />cross-flow
| <br />Cross-flow
|-
|-
| <br />Cr
| <br /><math>Cr</math>
| <br />critical
| <br />Critical
|-
|-
| <br />D
| <br /><math>D</math>
| <br />droplet
| <br />Droplet
|-
|-
| <br />g
| <br /><math>g</math>
| <br />gas
| <br />Gas
|-
|-
| <br />i
| <br /><math>i</math>
| <br />index number of a droplet
| <br />Index number of a droplet
|-
|-
| <br />in
| <br /><math>in</math>
| <br />atomiser inlet (inlet ports)
| <br />Atomiser inlet (inlet ports)
|-
|-
| <br />l
| <br /><math>l</math>
| <br />liquid
| <br />Liquid
|-
|-
| <br />m
| <br /><math>m</math>
| <br />inertia
| <br />Inertia
|-
|-
| <br />n
| <br /><math>n</math>
| <br />total number of droplets
| <br />Total number of droplets
|-
|-
| <br />o
| <br /><math>o</math>
| <br />exit orifice
| <br />Exit orifice
|-
|-
| <br />p
| <br /><math>p</math>
| <br />pressure
| <br />Pressure
|-
|-
| <br />r
| <br /><math>r</math>
| <br />relative
| <br />Relative
|-
|-
| <br />v0.1, v0.5, v0.9
| <br /><math>v0.1, v0.5, v0.9</math>
| <br />volumetric fractions 0.1, 0.5 and 0.9 of the total  droplet volume
| <br />Volumetric fractions 0.1, 0.5 and 0.9 of the total  droplet volume
|-
|-
| <br />µ
| <br /><math>\mu</math>
| <br />related to dynamic viscosity
| <br />Related to dynamic viscosity
|-
|-
| <br />σ
| <br /><math>\sigma</math>
| <br />related to surface tension
| <br />Related to surface tension
|-
|-
| <br /><math> \tau </math>
| <br /><math> \tau </math>
| <br />liquid film thickness
| <br />Liquid film thickness
|-
|-
| <br />
| <br />
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| style="font-weight:normal;" | <br />
| style="font-weight:normal;" | <br />
|-
|-
| <br />AC
| <br /><math>AC</math>
| <br />air core
| <br />Air core
|-
|-
| <br />fps
| <br /><math>fps</math>
| <br />frames per second
| <br />Frames per second
|-
|-
| <br />GT
| <br /><math>GT</math>
| <br />gas turbine
| <br />Gas turbine
|-
|-
| <br />HSC
| <br /><math>HSC</math>
| <br />high-speed camera
| <br />High-speed camera
|-
|-
| <br />HSV
| <br /><math>HSV</math>
| <br />high-speed vizualization
| <br />High-speed vizualization
|-
|-
| <br />LDA
| <br /><math>LDA</math>
| <br />laser Doppler anemometry,
| <br />Laser Doppler anemometry,
|-
|-
| <br />PDA
| <br /><math>PDA</math>
| <br />phase Doppler anemometry
| <br />Phase Doppler anemometry
|-
|-
| <br />PSA
| <br /><math>PSA</math>
| <br />pressure-swirl atomiser
| <br />Pressure-swirl atomiser
|-
|-
| <br />RSF
| <br /><math>RSF</math>
| <br />relative diameter span factor
| <br />Relative diameter span factor
|}
|}


Revision as of 19:39, 17 May 2023

Pressure-swirl spray in a low-turbulence cross-flow

Front Page

Introduction

Review of experimental studies

Description

Experimental Set Up

Measurement Quantities and Techniques

Data Quality and Accuracy

Measurement Data and Results


Abstract

Pressure-swirl atomisers (PSAs) produce fine spray and are used in many industrial, chemical and agricultural applications of sprays in flowing environments. The study examines spray from a small low-pressure PSA exposed to low-turbulence cross-flowing air. The PSA spray was investigated experimentally using phase Doppler anemometry (PDA) and high-speed visualisation (HSV). The atomiser sprayed water into cross-flowing air at varying flow velocities. The tests were provided at a newly developed wind tunnel facility in the Spray laboratory at Brno University of Technology. PDA results contain information on the size and velocity of individual droplets in multiple positions of the developed spray (after the liquid break up is completed). A high-speed camera (HSC) documented the complexity of the liquid discharge, the formation and break-up of the liquid film, and the spray morphology. The data is relevant to CFD engineers and scientists involved in modelling as they can highlight the crucial phenomena to be considered in numerical simulations of the disperse two-phase flow case. The case allows to study 1) liquid discharge and sheet formation, the primary break-up of the liquid sheet, 2) secondary break-up and spray formation and 3) the interaction of the sprayed liquid with surrounding air: gas–liquid mixing, droplet collisions, droplet clustering and droplet reposition.

  • Figure 1a: Spray image form high-speed imaging

    Figure 1a: Spray image form high-speed imaging

  • Figure 1b: Optical measurement using PDA (taken from [1])

    Figure 1b: Optical measurement using PDA (taken from [1])

References

  1. ↑ CEJPEK, Ondřej. Design and realization of an aerodynamic tunnel for spraying nozzles [online]. Brno, 2020 [cit. 2023-04-18]. Available from: https://www.vutbr.cz/studenti/zav-prace/detail/124871. Master thesis. Brno University of Technology

Nomenclature


Symbol
Description


Cross-section


Arrival time to the measurement volume


Bond number


Droplet concentration


Discharge coefficient


Mean droplet diameter


Diameter


Arithmetic mean diameter


Surface mean diameter


Sauter mean diameter


Force acting on a liquid element


Froude number


Gravitational acceleration


Nozzle dimension constant


Characteristic distance


Break-up distance


Velocity in Z-direction


Velocity in Y-direction


Wave number


Ohnesorge number


Pressure


Flow rate


Liquid-to-air momentum ratio


Radius


Reynolds number


Swirl number


Stokes number


Spray cone angle


Time


Transit time through the measurement volume


Turbulence intensity


Velocity


Phase shift between photomultipliers 1 and 2


Phase shift between photomultipliers 1 and 3


Swirl component of the velocity


Weber number


Cartesian coordinates



Greek symbols


Difference between the gas and droplet velocity


Nozzle efficiency


Dynamic viscosity


Liquid density


Surface tension



Indices


Aerodynamic


Air core


Swirl chamber


Cross-flow


Critical


Droplet


Gas


Index number of a droplet


Atomiser inlet (inlet ports)


Liquid


Inertia


Total number of droplets


Exit orifice


Pressure


Relative


Volumetric fractions 0.1, 0.5 and 0.9 of the total droplet volume


Related to dynamic viscosity


Related to surface tension


Liquid film thickness



Abbreviations


Air core


Frames per second


Gas turbine


High-speed camera


High-speed vizualization


Laser Doppler anemometry,


Phase Doppler anemometry


Pressure-swirl atomiser


Relative diameter span factor



Contributed by: Ondrej Cejpek, Milan Maly, Jan Jedelsky — Brno University of Technology

Front Page

Introduction

Review of experimental studies

Description

Experimental Set Up

Measurement Quantities and Techniques

Data Quality and Accuracy

Measurement Data and Results


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