Structure of Emulsion Cavitation Jet and Jet Peening Impact on the Fatigue of Plan Carbon Steel Q235A

2011 ◽  
Vol 189-193 ◽  
pp. 476-483
Author(s):  
Zhi Sun ◽  
Yan Wei Sui ◽  
Jun Li ◽  
Yan Ni Zhou
Keyword(s):  
Carbon Steel ◽  
High Speed ◽  
Test System ◽  
Water Jet ◽  
High Speed Photography ◽  
Strengthening Effect ◽  
Initial Stage ◽  
Jet Impact ◽  
Upstream Pressure ◽  
Crack Initiation Life

Due to developing the strengthening effect of liquid jet peening on the surface modification for metallic materials, in this study, an emulsion jet peening is produced by injecting a high-speed emulsion jet into an emulsion filled tank. The test system and fixed emulsion of cavitation jet was developed. High speed photography technique was used to observe and analysis the structure of emulsion cavitation jet at various upstream pressures . The results indicate that the structure of emulsion cavitation jet in terms of jet impact pressure, intensive degree and uniformity is better than that water jet. The jet structure depends on the jet pressure. The cavitation jet length increases rapidly at the initial stage and then it stabilizes after few milliseconds. The stabilized length of jet increases and the diverges angle decreases with increasing pressures. Specimens made of plan carbon steel (Q235A, China standard) were exposed to emulsion jet peening at the stand-off distances of 20 mm with a constant upstream pressure, 20 MPa for 60 s. The fatigue test shows that the crack initiation life by treatment of emulsion jet peening increases about 12.5% and 20.2% compared to water jet and unpeened specimen respectively.

Erosive Wear Of Natural Gas Pipes Due To High Velocity Jet Impact: Physical Examination And Experimental Study

2012 ◽  
Author(s):  
Z. A. Majid ◽  
R. Mohsin ◽  
M. Z. Yusof
Keyword(s):  
High Pressure ◽  
Carbon Steel ◽  
High Speed ◽  
Experimental Testing ◽  
Water Jet ◽  
Gas Jet ◽  
Water Pipe ◽  
Pipe Surface ◽  
Jet Impact ◽  
Pressure Water

A sequential failure of API 5L X42 (NPS8) carbon steel and SDR 17 medium density polyethylene (MDPE) pipes towards the high pressure water pipe was studied. Pipe’s failed specimen was physically examined and experimental testing was conducted by using high speed water jetting facility towards a similar NPS8 pipe specimen. High pressure water jet impact from leaked water pipe forms highly erosive water–soil slurry and this caused severely damaged on NPS8 carbon steel pipe surface. Thus, causing substantial losses of pipe coating materials and subsequent rapid thinning of pipe body occurred. Furthermore, weaker ground support causes instability to the MDPE pipe and leads to vertical descend towards high speed gas jet region exerted from failed NPS8 pipe. High impact gas jet physically hit the MDPE pipe at its opposite direction causing its rapid erosion. Key words: Liquid impact erosion; gas jet impact; solid particle impact; water jet impact

Ice breaking by a high-speed water jet impact

2022 ◽  
Vol 934 ◽  
Author(s):  
G.-Y. Yuan ◽  
B.-Y. Ni ◽  
Q.-G. Wu ◽  
Y.-Z. Xue ◽  
D.-F. Han
Keyword(s):  
High Speed ◽  
Water Jet ◽  
Crack Development ◽  
Water Tank ◽  
Water Jets ◽  
Cold Room ◽  
Water Region ◽  
Jet Impact ◽  
Plate Size ◽  
Series Of Experiments

Ice breaking has become one of the main problems faced by ships and other equipment operating in an ice-covered water region. New methods are always being pursued and studied to improve ice-breaking capabilities and efficiencies. Based on the strong damage capability, a high-speed water jet impact is proposed to be used to break an ice plate in contact with water. A series of experiments of water jet impacting ice were performed in a transparent water tank, where the water jets at tens of metres per second were generated by a home-made device and circular ice plates of various thicknesses and scales were produced in a cold room. The entire evolution of the water jet and ice was recorded by two high-speed cameras from the top and front views simultaneously. The focus was the responses of the ice plate, such as crack development and breakup, under the high-speed water jet loads, which involved compressible pressure ${P_1}$ and incompressible pressure ${P_2}$ . According to the main cause and crack development sequence, it was found that the damage of the ice could be roughly divided into five patterns. On this basis, the effects of water jet strength, ice thickness, ice plate size and boundary conditions were also investigated. Experiments validated the ice-breaking capability of the high-speed water jet, which could be a new auxiliary ice-breaking method in the future.

Effects of Diffuser Length on Cloud Cavitation in an Axisymmetrical Convergent-Divergent Nozzle

2015 ◽  
Author(s):  
Keiichi Sato ◽  
Naoya Takahashi ◽  
Yasuhiro Sugimoto
Keyword(s):  
High Speed ◽  
Pressure Effect ◽  
Water Jet ◽  
Video Observation ◽  
Fluid Machinery ◽  
Cloud Cavitation ◽  
Frame Difference ◽  
Upstream Pressure ◽  
Cavitating Hydrofoil ◽  
Unsteady Behavior

Unsteady behavior of periodic cloud cavitation is typically observed in the field of fluid machinery under a high speed liquid flow such as a cavitating hydrofoil as well as cavitating water jet. The instability of cloud cavitation remains to be completely solved though it has been confirmed that there are two instabilities which is an intrinsic instability of cavitation and a system instability. Sato, et al. have found through previous investigations that the pressure wave at the collapse of shedding clouds can make a trigger to cause a reentrant motion. In the present study, the authors focus on a cavitating water jet to investigate the cavitation aspects in an axisymmetrical convergent-divergent nozzle and examine an unsteady behavior of cloud cavitation through high speed video observation and image analysis based on the frame difference method. Especially, the authors study the effect of nozzle divergent part (diffuser) as well as the upstream pressure effect on cloud cavitation in the nozzle. As a result the authors have found that there are two kinds in the shedding pattern and the reentrant motion pattern for cloud cavitation depending on the nozzle diffuser length.

scholarly journals Experimental Study on Electric Potential Response Characteristics of Gas-Bearing Coal During Deformation and Fracturing Process

Processes ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 72 ◽  
Author(s):  
Zhonghui Li ◽  
Yue Niu ◽  
Enyuan Wang ◽  
Lanbo Liu ◽  
Honghao Wang ◽  
...  
Keyword(s):  
Damage Evolution ◽  
High Speed ◽  
Electrical Potential ◽  
Test System ◽  
Stress Change ◽  
High Speed Photography ◽  
Response Characteristics ◽  
Fracturing Process ◽  
Erosion Effect ◽  
Gas Bearing

Coal mass is deformed and fractured under stress to generate electrical potential (EP) signals. The mechanical properties of coal change with the adsorption of gas. To investigate the EP response characteristics of gas-bearing coal during deformation and fracture, a test system to monitor multi-parameters of gas-bearing coal under load was designed. The results showed that abundant EP signals were generated during the loading process and the EP response corresponded well with the stress change and crack expansion, and validated this with the results from acoustic emission (AE) and high-speed photography. The higher stress level and the greater the sudden stress change led to the greater EP abnormal response. With the increase of gas pressure, the confining action and erosion effect are promoted, causing the damage evolution impacted and failure characteristics changes. As a result, the EP response is similar while the characteristics were promoted. The EP response was generated due to the charge separation caused by the friction effect etc. during the damage and deformation of the coal. Furthermore, the main factors of the EP response were different under diverse loading stages. The presence of gas promoted the EP effect. When the failure of the coal occurred, EP value rapidly rose to a maximum, which could be considered as an anomalous characteristic for monitoring the stability and revealing failure of gas-bearing coal. The research results are beneficial for further investigating the damage-evolution process of gas-bearing coal.

The Application of CEL Technique to Simulate the Behavior of an Underwater Explosion Bubble in the Vicinity of a Rigid Wall

2020 ◽  
Vol 902 ◽  
pp. 126-139
Author(s):  
Anh Tu Nguyen
Keyword(s):  
Finite Element ◽  
High Speed ◽  
Bubble Dynamics ◽  
Underwater Explosion ◽  
Flow Simulation ◽  
Rigid Wall ◽  
Water Jet ◽  
Complex Structures ◽  
Explicit Finite Element ◽  
Jet Impact

The dynamic process of an underwater explosion (UNDEX) is a complex phenomenon that involves several facets. After detonation, the shockwave radially propagates at a high speed and strikes nearby structures. Subsequently, bubble oscillation may substantially damage the structures because of the whipping effect, water jet impact, and bubble pulse. This paper presents an application of explicit finite element analyses to simulate the process of an UNDEX bubble in the vicinity of rigid wall, in which the coupled Eulerian-Lagrangian (CEL) approach was developed to overcome the difficulties regarding the classical finite element method (FEM), large deformations, and flow simulation of fluid and gas. The results demonstrate that the method is well suited to manage the UNDEX bubble problem and can be used to model the major features of the bubble dynamics. Furthermore, the behavior of an UNDEX bubble near a rigid wall was also examined in the present study, which showed that the migration of the bubble and the development of the water jet are influenced strongly by the standoff distance between the initial bubble position and the wall. This method can be used in future studies to examine UNDEX bubbles in the vicinity of deformable and complex structures.

Effect of Nozzle Shape and Polymer Additives on Water Jet Appearance

1979 ◽  
Vol 101 (3) ◽  
pp. 304-308 ◽  
Author(s):  
J. W. Hoyt ◽  
J. J. Taylor
Keyword(s):  
Boundary Layer ◽  
High Speed ◽  
Water Jet ◽  
Boundary Layer Transition ◽  
Transition To Turbulence ◽  
Polymer Additives ◽  
High Speed Photography ◽  
Layer Transition ◽  
Spray Formation ◽  
Exit Surface

The effects of shape parameters on the performance of water-jet nozzles discharging in air were investigated using a camera specially adapted for jet photography. The boundary-layer developing on the exit surface of the nozzle is shown to account for the jet appearance revealed by high speed photography. Optimum nozzles seem to have the boundary-layer transition to turbulence inside the nozzle; transition outside the nozzle being accompanied by spray formation and early jet disruption. The effect of polymer additives seems to be earlier transition and a thinner turbulent boundary layer inside the nozzle which improves jet performance.

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.

Water-jet cavitation shocking as a novel array micro-forming technique

2020 ◽  
pp. 095440542098222
Author(s):  
Fuzhu Li ◽  
Peiyu He ◽  
Zhipeng Chen ◽  
Shangshuan Chen ◽  
Jun Guo ◽  
...  
Keyword(s):  
High Speed ◽  
Thickness Distribution ◽  
Water Jet ◽  
Impact Zone ◽  
Large Area ◽  
Micro Forming ◽  
Jet Impact ◽  
Microscopic Features ◽  
The Impact ◽  
Metallic Sheet

Micro-feature arrays and large-area complex microscopic features on thin metallic sheet play an important role in micro-components. A novel technique-submerged water-jet cavitation shocking-is presented to generate micro-feature arrays on 304 stainless foils in this paper. High-speed camera shadowgraph images of the cavitation cloud were employed to analyze the impact zone. Then the forming depth, uniformity of forming depth and the thickness distribution of the micro-feature arrays were also studied. The results show that the forming region can be categorized into the jet-impact-zone, the bubble-impact-zone and the periphery-impact-zone radially. Bubble-impact-zone peaks in the depth of array micro-forming. The forming depth increases with time while the uniformity decreases with time. The forming parts have a uniform thickness distribution.

Study on Flow Patterns and Separation Performance of Liquid-Gas Separator Units

2014 ◽  
Vol 1008-1009 ◽  
pp. 919-926
Author(s):  
Xue Qing Chen ◽  
Lei Tong
Keyword(s):  
High Speed ◽  
Separation Efficiency ◽  
Flow Patterns ◽  
Test System ◽  
High Speed Photography ◽  
Separation Performance ◽  
Discharge Process ◽  
Experimental Conditions ◽  
Operation Conditions ◽  
Gas Separator

Three liquid-gas separator units were designed and manufactured from transparent acrylic resin based on the concept of a new kind of validated high performance condenser. The separator units had different spaces between baffle and outlet arm or different header diameters. A visualization cold state test system was set up to explore the basic principle of liquid-gas separation and liquid discharge process, using air and water as the working fluids. Four kinds of liquid flow patterns were observed by the liquid staining and high-speed photography at inlet air superficial velocities from 1m/s to 15m/s and water superficial velocities from 0.0015m/s to 0.06m/s. The effects of operation conditions and structure parameters on the separation efficiency of the liquid-gas separator units were investigated. The results showed that under the experimental conditions, the separation efficiency was more than 70%, the separation efficiency could be improved by increasing the space between baffle and outlet arm as well as the header diameter.

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