Visualization of High Speed Liquid Jet Impaction on a Moving Surface

Summary

Two experimental devices for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device and a spinning disk device. The apparatuses are used to determine optimal approaches to the application of liquid friction modifier (LFM) onto rail tracks for top-of-rail friction control.

Abstract

Two apparatuses for examining liquid jet impingement on a high-speed moving surface are described: an air cannon device (for examining surface speeds between 0 and 25 m/sec) and a spinning disk device (for examining surface speeds between 15 and 100 m/sec). The air cannon linear traverse is a pneumatic energy-powered system that is designed to accelerate a metal rail surface mounted on top of a wooden projectile. A pressurized cylinder fitted with a solenoid valve rapidly releases pressurized air into the barrel, forcing the projectile down the cannon barrel. The projectile travels beneath a spray nozzle, which impinges a liquid jet onto its metal upper surface, and the projectile then hits a stopping mechanism. A camera records the jet impingement, and a pressure transducer records the spray nozzle backpressure. The spinning disk set-up consists of a steel disk that reaches speeds of 500 to 3,000 rpm via a variable frequency drive (VFD) motor. A spray system similar to that of the air cannon generates a liquid jet that impinges onto the spinning disc, and cameras placed at several optical access points record the jet impingement. Video recordings of jet impingement processes are recorded and examined to determine whether the outcome of impingement is splash, splatter, or deposition. The apparatuses are the first that involve the high speed impingement of low-Reynolds-number liquid jets on high speed moving surfaces. In addition to its rail industry applications, the described technique may be used for technical and industrial purposes such as steelmaking and may be relevant to high-speed 3D printing.

Introduction

This research aims to determine strategies for applying LFM (Liquid Friction Modifier) in liquid jet form onto a moving surface while attaining high degrees of transfer efficiency and uniform deposition results. Achieving this objective involves developing a comprehensive understanding of factors that affect liquid jet impingement on moving surfaces.

The project is motivated by a need to improve the efficiency of lubrication application techniques used in the rail sector. As a means of reducing fuel consumption and locomotive maintenance costs, a thin film of friction modifying agent is now being applied to the upper rail surface of convent....

Protocol

1. Spinning Disk Device

1. Identify desired test conditions and record test conditions in a table (e.g., ambient temperature, fluid properties, jet and surface speed, etc.).
2. Preparation of Materials
   1. Prepare glycerin-water or PEO-glycerin-water solutions for the impingement tests.
      1. In the case of PEO-glycerin-water tests, gradually dissolve 4.5 g of PEO powder (viscosity-average molecular weights of one million and four million) into 1495.5 g of distilled water under gentle magnetic stirring over a 24 hr period. Avoid excessively agitating the PEO sample to prevent mechanical degradation.
      2. Gradual....

Results

As discussed in the introductory section, the three main behaviors associated with liquid jet impingement are deposition, splatter and splash. These jet impingement behaviors are observed using video data recorded by high-speed cine cameras positioned at various optical points. Examples of still images, obtained from the video recordings, which depict the three liquid jet outcomes are shown in Figure 3. Figure 3A depicts liquid jet deposition, in which the jet flows in a completely strai.......

Discussion

The projectile used for the air cannon set-up is composed of a lightweight, wooden base. Though the wooden material chips slightly after numerous tests, it has been found to absorb kinetic energy more effectively than projectiles composed of materials such as plastic or metal, which tend to shatter upon impacting the stop mechanism. The dimensions of the wooden projectile are designed to closely match the steel barrel interior, thus restricting air leakage. A 1/8” thick rubber sheet secured between two layers of pl.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Equipment for Air Cannon Set-Up
30-gallon air tank	Steel Fab	A10028
Solenoid actuated poppet valve	Parker Hannifin Corp.	#16F24C2164A3F4C80
1.5" NPT rubber hose
Rectangular steel tubing
Stop mechanism	Customized
Stainless steel plates	Customized
Wooden projectile	Customized
1 kW high-intensity incandescent light	Photographic Analysis Ltd.	T986851
Light diffuser sheet
Optic sensor	BANNER	SM312LV
Equipment for Spinning Disc Set-Up
Motor	WEG	TEFC-W22
Bearings
Disk	Customized
Fiber optic light source	Fiberoptics Technology Incorporated	MO150AC
High intensity LED array	Torshare Ltd.	TF10CA
Vacuum	Ridge Tool Company	WD09450
Interrupter	Customized
Shared Equipment for Both Devices
Phantom v611 high-speed cine camera	Vision Research Inc.	V611
Phantom v12 high-speed cine camera	Vision Research Inc.	V12
Zoom 7000 lens	Navitar Inc.	Zoom 7000
Zoom 6000 lens	Navitar Inc.	Zoom 6000
Compressed nitrogen tank	Praxair Technology, Inc.
Pressure regulator	Praxair Technology, Inc.	PRS20124351CGA
Hose for compressed nitrogen	Swagelok Company	SS-CT8SL8SL8-12
Hose for liquid	Swagelok Company	SS-7R8TA8TA8
Accumulator	Accumulators, Inc.	A131003XS
Solenoid Valve	Solenoid Solutions Inc.	2223X-A440-00
Pressure transducer	WIKA Instruments Ltd	#50398083
Nozzle assembly	Customized
Glycerin
Poly(ethylene oxide)