High-Speed Observation of a Cavitating Jet in Air

2005 ◽  
Vol 127 (6) ◽  
pp. 1095-1101 ◽  
Author(s):  
Hitoshi Soyama
Keyword(s):  
High Speed ◽  
Video Recording ◽  
Injection Pressure ◽  
Practical Method ◽  
Water Jet ◽  
High Speed Photography ◽  
Low Speed ◽  
High Speed Video ◽  
Cavitating Jets ◽  
Cavitating Jet

The use of cavitation impact is a practical method for improving the fatigue strength of metals in the same way as shot peening. In the case of peening using cavitation impact, cavitation is produced by a high-speed submerged water jet with cavitation, i.e., a cavitating jet. A cavitating jet in air was successfully generated by injecting a high-speed water jet into a low-speed water jet injected into air using a concentric nozzle. In order to investigate the various appearances of cavitating jets in air, an observation was carried out using high-speed photography and high-speed video recording. In this study, periodical shading of the cavitation cloud was observed and the frequency of the shading was found to be a function of the injection pressure of the low-speed water jet. Unsteadiness of the low-speed water jet, which is related to the periodical shading of the cloud, was also observed.

Introduction of Compressive Residual Stress Using a Cavitating Jet in Air

2004 ◽  
Vol 126 (1) ◽  
pp. 123-128 ◽  
Author(s):  
Hitoshi Soyama
Keyword(s):  
Residual Stress ◽  
Mass Loss ◽  
Shot Peening ◽  
High Speed ◽  
Compressive Residual Stress ◽  
Injection Pressure ◽  
Water Jet ◽  
Low Speed ◽  
Aluminum Specimen ◽  
Cavitating Jet

Cavitation impact from a cavitation jet, which is formed from bubbles induced by a high-speed water jet in water, can be used for surface modification in a similar manner to shot peening. A cavitating jet is normally produced by injecting a high-speed water jet into a water-filled chamber. It is possible to make a cavitating jet in air by injecting a high-speed water jet into a concentric low-speed water jet that surrounds the high-speed jet. In order to demonstrate this, a high-speed water jet with a concentric low-speed water jet was impacted onto an aluminum specimen to observe the pattern of erosion. The mass loss of the specimen was weighed to measure the capability of the jet, since a more powerful jet produces a larger mass loss. It was shown that the combination of high- and concentric low-speed water jets produced a typical erosion pattern such as that obtained using a cavitating jet in a water-filled chamber. When the injection pressure of the concentric low-speed water jet was optimized, the capability of the cavitating jet in air was much greater than that of a cavitating jet in a water-filled chamber. It was demonstrated that an optimized cavitating jet in air introduced more compressive residual stress in the surface of tool steel alloy than that from a cavitating jet in a water-filled chamber. In addition, this stress was larger than that induced by shot peening. The peened surface was also less rough compared with shot peening.

scholarly journals Cavitating Jet: A Review

2020 ◽  
Vol 10 (20) ◽  
pp. 7280 ◽  
Author(s):  
Hitoshi Soyama
Keyword(s):  
High Speed ◽  
Injection Pressure ◽  
Water Jet ◽  
Cavitation Number ◽  
Estimation Methods ◽  
Metallic Materials ◽  
Hydraulic Machinery ◽  
Cavitating Jets ◽  
Mechanical Surface ◽  
Cavitating Jet

When a high-speed water jet is injected into water through a nozzle, cavitation is generated in the nozzle and/or shear layer around the jet. A jet with cavitation is called a “cavitating jet”. When the cavitating jet is injected into a surface, cavitation is collapsed, producing impacts. Although cavitation impacts are harmful to hydraulic machinery, impacts produced by cavitating jets are utilized for cleaning, drilling and cavitation peening, which is a mechanical surface treatment to improve the fatigue strength of metallic materials in the same way as shot peening. When a cavitating jet is optimized, the peening intensity of the cavitating jet is larger than that of water jet peening, in which water column impacts are used. In order to optimize the cavitating jet, an understanding of the instabilities of the cavitating jet is required. In the present review, the unsteady behavior of vortex cavitation is visualized, and key parameters such as injection pressure, cavitation number and sound velocity in cavitating flow field are discussed, then the estimation methods of the aggressive intensity of the jet are summarized.

Research on the Characteristic of Diesel Elastic-Plate Impingement Spray

2012 ◽  
Vol 433-440 ◽  
pp. 116-122
Author(s):  
Chang Yuan Wang ◽  
Fu Shui Liu ◽  
Xiang Rong Li
Keyword(s):  
Experimental Research ◽  
Elastic Plate ◽  
High Speed ◽  
Incident Angle ◽  
Injection Pressure ◽  
High Speed Photography ◽  
Research Results ◽  
Free Jet ◽  
Constant Volume Chamber ◽  
Spray Droplets

A series of experimental research results on the characteristic of diesel elastic-plate impingement spray using High Speed Photography camera are presented in this paper. The experiments were carried out in a constant volume chamber specially designed, which can hold a high ambiance pressure. The special fixed device was designed so that the elastic-plate can be fixed on the spray path, meanwhile the spray incident angle and height can be changed. The free jet spray and elastic-plate impingement spray was compared under the same experimental condition including different injection pressure and different background pressure. Experimental research showed that impingement spray droplets diffuse more quickly than free jet spray.

scholarly journals High-speed Video Recording of Particle Trajectory via Rotating Chute of Nagoya No.3 Blast Furnace and its Comparison with Simulated Behavior Using DEM

2017 ◽  
Vol 57 (2) ◽  
pp. 272-278 ◽  
Author(s):  
Hiroshi Mio ◽  
Toshiki Nakauchi ◽  
Yuuki Kawaguchi ◽  
Takashi Enaka ◽  
Yoichi Narita ◽  
...  
Keyword(s):  
Blast Furnace ◽  
High Speed ◽  
Particle Trajectory ◽  
Video Recording ◽  
High Speed Video

High-speed video recording with the TDAS

1990 ◽  
Author(s):  
Daniel W. Liu ◽  
Eric D. Griesheimer ◽  
Lynn O. Kesler
Keyword(s):  
High Speed ◽  
Video Recording ◽  
High Speed Video

Direct Water Injection to Improve Diesel Spray Combustion

2003 ◽  
Author(s):  
Koji Takasaki ◽  
Tatsuo Takaishi ◽  
Hiroyuki Ishida ◽  
Keijirou Tayama
Keyword(s):  
Diesel Engines ◽  
High Speed ◽  
Fuel Injection ◽  
Nox Reduction ◽  
Water Injection ◽  
Injection Pressure ◽  
Injection System ◽  
Injection Hole ◽  
Low Speed ◽  
Direct Water Injection

Now, it is essential to apply some measures for NOx reduction to low-speed diesel engines emitting much more NOx than high-speed engines. At the same time PM emission must be reduced especially when bunker fuel or heavy fuel is burned. This paper describes the applications of SFWI (Stratified Fuel Water Injection) system and DWI (Direct Water Injection) system to large sized diesel engines to reduce NOx and PM emission. SFWI system makes it possible to inject water during fuel injection from the same nozzle hole without mixing the liquids. DWI system injects water with high injection pressure from the other injection hole than the fuel injection hole into the combustion chamber directly. For testing both the systems, a 2-stroke-cycle low-speed test engine was used.

scholarly journals Temperature evaluation of a hyper-rapid plasma jet by the method of high-speed video recording

2016 ◽  
Vol 124 ◽  
pp. 012001
Author(s):  
A E Rif ◽  
V V Cherevko ◽  
A S Ivashutenko ◽  
N V Martyushev ◽  
N Ye Nikonova
Keyword(s):  
High Speed ◽  
Video Recording ◽  
Plasma Jet ◽  
High Speed Video
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