Abstract <p>The laser time-of-flight method for measuring droplet velocities and sizes in a wide range of pressure characteristics of pneumatic nozzles is tested. The calculation of the sizes is based on high-speed measuring of the delay in scattering orders when a droplet crosses a laser beam. The velocities are measured by the droplet flight time between two laser beams. Two nozzles with coaxial liquid supply at an angle to the air flow are considered as an example. A feature of the mode of such nozzles is the requirement for a high air flow pressure relative to the pressure of the sprayed liquid. The operating features of pneumatic nozzles of different configurations when spraying liquid under low air pressure conditions are determined. The droplet parameters are measured using the Spray Spy<InlineEquation ID="IEq1"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11974_2025_8465_Article_IEq1.gif" Format="GIF" Height="13" Rendition="HTML" Resolution="72" Type="Linedraw" Width="13" /> </InlineMediaObject> <EquationSource Format="TEX">\({}^{\circledR}\)</EquationSource>  </InlineEquation> device (AOM-Systems GmbH) designed for measurements under low pressure, when the spray quality is not optimal, since the flow contains both low-inertia small droplets and high-inertia large droplets. It is found that the device allows simultaneous recording of spherical droplets from 5 to 200 <InlineEquation ID="IEq2"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11974_2025_8465_Article_IEq2.gif" Format="GIF" Height="12" Rendition="HTML" Resolution="72" Type="Linedraw" Width="15" /> </InlineMediaObject> <EquationSource Format="TEX">\(\mu\)</EquationSource>  </InlineEquation>m in size at velocities from 2 to 120 m s<InlineEquation ID="IEq3"> <InlineMediaObject> <ImageObject Color="BlackWhite" FileRef="11974_2025_8465_Article_IEq3.gif" Format="GIF" Height="11" Rendition="HTML" Resolution="72" Type="Linedraw" Width="18" /> </InlineMediaObject> <EquationSource Format="TEX">\({}^{-1}\)</EquationSource>  </InlineEquation>. The greatest spread of droplets in size and velocity is observed when liquid is supplied to the air flow at an angle. The jet structure of the spray cone of the nozzles is revealed by the method of visualization in backlight.</p>

Investigation of Pneumatic Nozzle Operation Features over a Wide Range of Pressure Characteristics Using Laser Time-of-Flight Method

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发表日期：

2025年6月1日

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A. S. Lebedev,
A. G. Savitsky,
A. S. Severin,
V. M. Dulin,
S. V. Skryabikov,
A. V. Vishev

摘要

Abstract

The laser time-of-flight method for measuring droplet velocities and sizes in a wide range of pressure characteristics of pneumatic nozzles is tested. The calculation of the sizes is based on high-speed measuring of the delay in scattering orders when a droplet crosses a laser beam. The velocities are measured by the droplet flight time between two laser beams. Two nozzles with coaxial liquid supply at an angle to the air flow are considered as an example. A feature of the mode of such nozzles is the requirement for a high air flow pressure relative to the pressure of the sprayed liquid. The operating features of pneumatic nozzles of different configurations when spraying liquid under low air pressure conditions are determined. The droplet parameters are measured using the Spray Spy \({}^{\circledR}\) device (AOM-Systems GmbH) designed for measurements under low pressure, when the spray quality is not optimal, since the flow contains both low-inertia small droplets and high-inertia large droplets. It is found that the device allows simultaneous recording of spherical droplets from 5 to 200 \(\mu\) m in size at velocities from 2 to 120 m s \({}^{-1}\) . The greatest spread of droplets in size and velocity is observed when liquid is supplied to the air flow at an angle. The jet structure of the spray cone of the nozzles is revealed by the method of visualization in backlight.