Combined Numerical and Experimental Investigation of the Cavitation Erosion Process

2015 ◽  
Vol 137 (5) ◽  
Author(s):  
Wang Jian ◽  
Martin Petkovšek ◽  
Liu Houlin ◽  
Brane Širok ◽  
Matevž Dular
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
High Speed ◽  
Cavitation Erosion ◽  
The Other ◽  
Damage Growth ◽  
Erosion Process ◽  
Time Step ◽  
Erosion Damage ◽  
Flow Simulations

We are comparing results of numerical simulations against high-speed simultaneous observations of cavitation and cavitation erosion. We performed fully compressible, cavitating flow simulations to resolve the formation of the shock waves at cloud collapse—these are believed to be directly related to the formation of the damage. Good agreements were noticed between calculations and tests. Two high pressure peaks were found during one cavitation cycle. One relates to the cavitation collapse and the other one corresponds to the cavitation shed off, both contributing to a distinctive stepwise erosion damage growth pattern. Additional, more precise, simulations with much shorter time step were performed to investigate the processes of cavitation collapse and shedding off in more detail. There the importance of small cavitation structures which collapse independently of the main cloud was found. The present work shows a great potential for future development of techniques for accurate predictions of cavitation erosion by numerical means only.

Experimental Investigation on Rapid Evaporation of High-Pressure Liquids due to Depressurization

2012 ◽  
Author(s):  
Qiaoling Zhang ◽  
Qincheng Bi ◽  
Zesen Nie ◽  
Jun Liang ◽  
Yajun Guo ◽  
...  
Keyword(s):  
Experimental Investigation ◽  
High Pressure ◽  
High Speed ◽  
Initial Conditions ◽  
Initial Pressure ◽  
Fluid Temperature ◽  
Shape Variation ◽  
Nitrogen Gas ◽  
Test Vessel ◽  
Variation Characteristics

This paper reports an experimental investigation of rapid evaporation process of high-pressure ethanol liquid during depressurization. The study focused on pressure and temperature transients with the influence of different initial conditions, and the shape variation was recorded via a high speed camera. During an experiment, the ethanol liquid was contained in a small round tube with a diameter 10mm in the test vessel, and a thermocouple was put within the fluid which was used to measure the fluid temperature during the depressurization. The predetermined pressure was provided by the high-pressure nitrogen gas, and the process of quick depressurization was started by opening the magnetic valve, which was connected with the test vessel. The transitions of the pressure and the fluid temperature were recorded by the NI data collection system. According to the experimental results, during the fast pressure drop, with the same initial temperature and other test conditions, the higher the initial pressure is, the faster the liquid temperature decreases, and the lower the minimum temperature reaches. In addition, the effect of initial fluid conditions, initial environmental pressure on temperature transition and so on are summed up and are experimentally analyzed on the fluid temperature change under the same test equipment. Also, the variation characteristics of kerosene fluid were compared with ethanol liquid under the same experiment conditions.

scholarly journals The relation between the high speed submerged cavitating jet behaviour and the cavitation erosion process

2016 ◽  
Vol 83 ◽  
pp. 27-38 ◽  
Author(s):  
Ezddin Hutli ◽  
Milos S. Nedeljkovic ◽  
Nenad A. Radovic ◽  
Attila Bonyár
Keyword(s):  
High Speed ◽  
Cavitation Erosion ◽  
Erosion Process ◽  
Cavitating Jet

Experimental Investigation on the Failure Mechanism of Grooved Steel Plate Impacted by Projectile with Different Nose Shapes

2020 ◽  
Vol 846 ◽  
pp. 162-166
Author(s):  
Nan Zhou ◽  
Jin Xiang Wang ◽  
Zong Bao Tong ◽  
Song Ze Tang
Keyword(s):  
Experimental Investigation ◽  
Failure Mechanism ◽  
Steel Plate ◽  
Tensile Deformation ◽  
Metal Plate ◽  
The Other ◽  
Penetration Process ◽  
Erosion Damage ◽  
Ballistic Experiment ◽  
Nose Shape

In order to study the penetration performance of the tandem warhead composed of a front circular shaped charge and a rear penetration projectile, a grooved steel plate was processed to simulate the effect of circular shaped jets on metal plate, then the failure mechanism of the grooved steel plate impacted by rear projectile was investigated by ballistic experiment, meanwhile, the effect of projectile nose shape on the failure mechanism was also analyzed. The results show that the main failure mechanism of grooved steel plate is ductile tensile deformation or damage when the projectile impacted on the inner plate body and the depth of the pre-splitting groove is not big enough (usually more than 4mm), on the other hand, the circumferential sheared fracture of the bottom of the groove occurred when the depth of the pre-splitting groove is not less than 4mm. The oval projectile body has much greater erosion damage than rod-shaped projectile during the penetration process.

EXPERIMENTAL INVESTIGATION OF THE INFLUENCE OF VORTEX GENERATORS AND LIQUID INJECTION ON NOISE IN HIGH-SPEED JETS

2012 ◽  
Vol 43 (4) ◽  
pp. 481-496 ◽  
Author(s):  
Valeriy Ivanovich Zapryagaev ◽  
Nikolay Petrovich Kiselev ◽  
Dmitriy Andreevich Gubanov
Keyword(s):  
Experimental Investigation ◽  
High Speed ◽  
Vortex Generators ◽  
Liquid Injection

Cyclone Bomb hits Southern Brazil in 2020

2020 ◽  
Vol 3 (3) ◽  
Author(s):  
Ricardo Gobato ◽  
Alireza Heidari
Keyword(s):  
High Pressure ◽  
Atmospheric Pressure ◽  
High Speed ◽  
Satellite Images ◽  
The State ◽  
Southern Brazil ◽  
Santa Catarina ◽  
High Area ◽  
South Of Brazil ◽  
Rapid Drop

An “explosive extratropical cyclone” is an atmospheric phenomenon that occurs when there is a very rapid drop in central atmospheric pressure. This phenomenon, with its characteristic of rapidly lowering the pressure in its interior, generates very intense winds and for this reason it is called explosive cyclone, bomb cyclone. With gusts recorded of 116 km/h, atmospheric phenomenon – “cyclone bomb” (CB) hit southern Brazil on June 30, the beginning of winter 2020, causing destruction in its influence over. One of the cities most affected was Chapecó, west of the state of Santa Catarina. The satellite images show that the CB generated a low pressure (976 mbar) inside it, generating two atmospheric currents that moved at high speed. In a northwest-southeast direction, Bolivia and Paraguay, crossing the states of Parana and Santa Catarina, and this draft that hit the south of Brazil, which caused the destruction of the affected states.  Another moving to Argentina, southwest-northeast direction, due to high area of high pressure (1022 mbar). Both enhanced the phenomenon.

YSS YXM4

Alloy Digest ◽  
2019 ◽  
Vol 68 (11) ◽  
Keyword(s):  
High Pressure ◽  
High Temperature ◽  
Physical Properties ◽  
Tool Steel ◽  
High Speed ◽  
Temperature Performance

Abstract YSS YXM4 is a cobalt-alloyed molybdenum high-speed tool steel with resistance to abrasion, seizure, and deformation under high pressure. This datasheet provides information on composition, physical properties, and hardness. It also includes information on high temperature performance. Filing Code: TS-780. Producer or source: Hitachi Metals America, Ltd.

Experimental Investigation of aluminum doping crumb rubber/epoxy composite in reciprocating motion

2015 ◽  
Vol 3 ◽  
pp. 1
Author(s):  
Goutam Chandra Karar ◽  
Nipu Modak
Keyword(s):  
Experimental Investigation ◽  
Coefficient Of Friction ◽  
Epoxy Composite ◽  
Normal Load ◽  
Crumb Rubber ◽  
The Other ◽  
Reciprocating Motion ◽  
Molding Process ◽  
Friction Tester ◽  
The Coefficient Of Friction

The experimental investigation of reciprocating motion between the aluminum doped crumb rubber /epoxy composite and the steel ball has been carried out under Reciprocating Friction Tester, TR-282 to study the wear and coefficient of frictions using different normal loads (0.4Kg, 0.7Kgand1Kg), differentfrequencies (10Hz, 25Hz and 40Hz).The wear is a function of normal load, reciprocating frequency, reciprocating duration and the composition of the material. The percentage of aluminum presents in the composite changesbut the other components remain the same.The four types of composites are fabricated by compression molding process having 0%, 10%, 20% and 30% Al. The effect of different parameters such as normal load, reciprocating frequency and percentage of aluminum has been studied. It is observed that the wear and coefficient of friction is influenced by the parameters. The tendency of wear goes on decreasing with the increase of normal load and it is minimum for a composite having 10%aluminum at a normal load of 0.7Kg and then goes on increasing at higher loads for all types of composite due to the adhesive nature of the composite. The coefficient of friction goes on decreasing with increasing normal loads due to the formation of thin film as an effect of heat generation with normal load.

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