Numerical Simulation in Nozzle Outflow of Post-Mixed Water-Jet Peening

2013 ◽  
Vol 448-453 ◽  
pp. 1173-1178 ◽  
Author(s):  
Xing Dong ◽  
Wei Yang ◽  
Hai Lu Zhang
Keyword(s):  
Flow Field ◽  
Water Flow ◽  
Axial Velocity ◽  
Dynamic Pressure ◽  
Water Jet ◽  
Standoff Distance ◽  
Turbulent Characteristics ◽  
Euler Model ◽  
Two Phases ◽  
Mixed Water

In order to achieve movement rule of post-mixed water jet outflow field, post-mixed water jet peening nozzle flow field were simulated by FLUENT software, according to their turbulent characteristics, the mathematical model adopted Euler model, turbulence model adopted the standard kε model. Analyzed the peening pressure and peening standoff distance on the influence of outflow field of liquid-solid two phases-flow axial dynamic pressure and axial velocity, the results show that in different peening pressure, water flow field and pill flow field of axial velocity and the axial dynamic pressure both are symmetrical distribution, and their value increased with the increase of peening pressure to raise, decreases with the increase of peening standoff distance, even, with the increase of length of pill nozzle water flow field of axial velocity decreases, and pill flow field of axial velocity increases. When the peening pressure is 14 MPa, peening standoff distance is 30 mm, length of pill nozzle is 55 mm, maximum axial dynamic pressure of the outflow field is 3.18 MPa, the maximum axial velocity of water flow field and pill flow field respectively are 71.3 m/s and 69.6 m/s.

Effect of Nozzle Outlet Type On the Flow Field Velocity and Impact Pressure of High Pressure Water Jet Peening

2022 ◽  
Author(s):  
Hong-xiang Zheng ◽  
Yun Luo ◽  
Jing-Yu Zang ◽  
Qian Zhang
Keyword(s):  
Axial Velocity ◽  
Dynamic Pressure ◽  
Central Area ◽  
Water Jet ◽  
The Other ◽  
Impact Pressure ◽  
Axial Distance ◽  
Nozzle Outlet ◽  
Pressure Area ◽  
Jet Velocity

Abstract Water jet peening can effectively improve the fatigue strength of metal materials, and the outlet shape of nozzle greatly affects the effect of water jet peening. In this paper, the effects of nozzle outlet shape on water jet velocity and impact pressure is studied by numerical simulation, and the jet velocity and dynamic pressure for different standoff distances are also discussed. The results show that the water jets of square, circular and triangular nozzles are highly concentrated, and the water jet of elliptical nozzles is the most divergent. The axial velocity attenuation of the square nozzle along the axis is slower than that of the other three nozzles. The water axial velocity of the elliptical nozzle attenuates fastest and the length of the core segment of the water jet is the smallest. Within a certain axial distance, the dynamic pressure area in the central area of the elliptical water jet is obviously larger than that of the other three nozzles, and the effective treatment range is large, which is more suitable for the welding surface strengthening operation.

Water Veil Effect to Control Splashing from the Pulsed Water Jet Device: Minimizing the Potential Risk of Dissemination Using Surgical Aspirators

2018 ◽  
Vol 79 (04) ◽  
pp. 309-315 ◽  
Author(s):  
Atsushi Nakayashiki ◽  
Atsuhiro Nakagawa ◽  
Motohiko Sato ◽  
Fusako Mochizuki ◽  
Toshiki Endo ◽  
...  
Keyword(s):  
Water Flow ◽  
Potential Risk ◽  
Input Voltage ◽  
Water Jet ◽  
Standoff Distance ◽  
Suction Pressure ◽  
Porcine Brain ◽  
Additional Water ◽  
Pulsed Water Jet ◽  
Brain Phantom

Objective Maximum resection with minimum damage to normal structures is required for a better clinical outcome. Several efficient surgical devices such as the Cavitron ultrasonic surgical aspirator are available. Our group developed the actuator-driven pulsed water jet (ADPJ) to dissect soft tissue with vessel preservation. Although these devices are very effective for resection, tumor seeding is a potential risk. The present study investigated the control of splashing during ADPJ use. We demonstrate the effect of additional water flow around the instrument tip to veil the splashing. Methods Pulsed water jet was ejected from the tip of the ADPJ nozzle. Effects of ADPJ parameters such as input voltage, suction pressure, and distance between the nozzle and the target (standoff distance) on the amount of splashing were analyzed. Methylene blue solution was ejected on photo paper, gelatin brain phantom, and porcine brain harvested and subsequently immersed into physiologic saline to quantify the amount of splashing. Results High-input voltage and a long standoff distance had significant correlations with large amounts of splashing (r > 0.5; p < 0.01). However, suction pressure had no correlation (r = 0.23). Additional water flow combined with the ADPJ decreased the amount of splashing. A high-speed camera recording revealed that the additional water flow formed a water veil that prevented droplet dispersion, as confirmed with experiments using the brain phantom and porcine brain, in which the irregularity and elasticity are specific. Conclusions The veil effect of additional water flow is important to reduce splashing during ADPJ use and can minimize the potential risk of dissemination and enhance the safety of the ADPJ.

scholarly journals Research on the Influence of External Parameters of Fan-Type Nozzle on Water Jet Performance

2020 ◽  
Vol 2020 ◽  
pp. 1-16
Author(s):  
Baofu Kou ◽  
Pengliang Huo ◽  
Xiaohua Hou
Keyword(s):  
Flow Field ◽  
Dynamic Pressure ◽  
Target Surface ◽  
Water Jet ◽  
Inlet Pressure ◽  
Normal Line ◽  
Washing Process ◽  
Pressure Water ◽  
High Pressure Water Jet ◽  
Important Position

At present, high-pressure water jet technology occupies a very important position in the automobile washing industry. Some automatic washers cannot meet the washing requirements in the washing process due to unreasonable arrangement of nozzles on their spray rods. Based on the theory of computational fluid dynamics (CFD), the internal and external flow field model of the nozzle are established in this paper. Fluent is used to simulate and analyze the flow field, and the external parameters of the nozzle on the side spray bar of the automatic automobile washer are optimized. The simulation results show that after the nozzle and the normal line of the automobile surface are inclined at a certain angle, the target surface is affected not only by normal striking force but also by tangential pushing force, which makes stains easier to remove. The washing effect is the best when the nozzle is inclined 30° to the normal line of the automobile surface. Increasing the nozzle inlet pressure will increase the dynamic pressure on the automobile surface, but the increase of dynamic pressure will decrease after increasing to a certain pressure. The inlet pressure has little effect on the area covered by water jet. The reasonable matching results of jet angle, nozzle spacing, and nozzle distance from the automobile surface (target distance) obtained by numerical simulation can not only make the automobile surface completely covered and cleaned but also ensure less jet interference and no waste of water from adjacent nozzles. The above research conclusions can provide a basic theoretical basis for the optimal design of automatic automobile washing.

An Investigation of the Flow and Global Performance in a Water-Jet Axial Flow Pump Based on CFD and Inverse Design Method

2005 ◽  
Author(s):  
Hong Gao ◽  
Wanlai Lin ◽  
Fangming Ye
Keyword(s):  
Flow Field ◽  
Radial Distribution ◽  
Axial Velocity ◽  
Design Method ◽  
Water Jet ◽  
Design Flow ◽  
Inverse Design ◽  
Cfd Modeling ◽  
Global Performance ◽  
Inverse Design Method

A new inverse design method based on non-constant distribution of circulation and axial velocity along the radial direction is used to design a pump impeller and a stator. The radial distribution of axial velocity at the design flow rate is calculated when an empirical radial distribution of circulation is given. CFD modeling of the global performance and the detailed flow field is performed using TASCflow software. A standard k-ε turbulence model combined with standard wall functions is used. A special mixing plane approach is employed to simulate the rotator-stator coupling flow field. The global performances of the water-jet pump, the radial distribution of velocity components at the exit of the impeller are also measured. Good agreement of the global performance, such as the pressure rise, the power and the efficiency, between CFD and experiment is obtained. The detailed velocity fields from inviscid analysis, CFD and experiment are compared and investigated.

Grinding Fluid Flow Field Modeling and Multi-Parameter Numerical Analysis Based on Smooth Model

2010 ◽  
Vol 156-157 ◽  
pp. 948-955
Author(s):  
Guang Yao Meng ◽  
Ji Wen Tan ◽  
Yi Cui
Keyword(s):  
Fluid Flow ◽  
Numerical Analysis ◽  
Flow Field ◽  
Dynamic Pressure ◽  
Grinding Wheel ◽  
Lubricating Film ◽  
Fluid Field ◽  
Grinding Fluid ◽  
Smooth Model ◽  
Area Increase

Relative motion between grinding wheel and workpiece makes the lubricant film pressure formed by grinding fluid in the grinding area increase, consequently, dynamic pressure lubrication forms. The grinding fluid flow field mathematical model in smooth grinding area is established based on lubrication theory. The dynamic pressure of grinding fluid field, flow velocity and carrying capacity of lubricating film are calculated by the numerical analysis method. An analysis of effect of grinding fluid hydrodynamic on the total lifting force is performed, and the results are obtained.

scholarly journals Influence of Upstream Disturbances on the Vortex Structure of Francis Turbine Based on the Criteria of Identification of Various Vortexes

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7626
Author(s):  
Tao Guo ◽  
Lihui Xu ◽  
Wenquan Wang
Keyword(s):  
Flow Field ◽  
Vortex Structure ◽  
Draft Tube ◽  
Francis Turbine ◽  
Vortex Identification ◽  
Vortex Rope ◽  
Blade Passage ◽  
Small Opening ◽  
Turbulent Characteristics ◽  
Passage Vortex

The inter-blade passage vortex, the vortex rope of the draft tube, and the vortex in the guide apparatus are the characteristics of flow instability of the Francis turbine, which may lead to fatigue failure in serious cases. In the current study, in order to accurately capture the transient turbulent characteristics of flow under different conditions and fully understand the flow field and vortex structure, we conduct a simulation that adopts sliding grid technology and the large-eddy simulation (LES) method based on the wall-adapting local eddy viscosity (WALE) model. Using the pressure iso-surface method, the Q criterion, and the latest third-generation Liutex vortex identification method, this study analyzes and compares the inter-blade passage vortex, the vortex rope of the draft tube, and the outflow and vortex in the guide apparatus, focusing on the capture ability of flow field information by various vortex identification methods and the unique vortex structure under the condition of a small opening. The results indicate that the dependence of Liutex on the threshold is small, and the scale range of the flow direction vortex captured by Liutex is wider, but the ability of the spanwise vortex is relatively weak. The smaller the opening, the more disorderly the vortexes generated in each component and the more unstable the flow field. In the draft tube, the original shape of the vortex rope is destroyed due to the interaction between vortexes. Under the condition of a small opening, an inter-blade passage vortex is generated, affecting the efficient and stable operation of the turbine.

scholarly journals Experimental Study of the Jet Engine Exhaust Flow Field of Aircraft and Blast Fences

2015 ◽  
Vol 27 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Haifu Wang ◽  
Liangcai Cai ◽  
Xiaolei Chong ◽  
Hao Geng
Keyword(s):  
Experimental Study ◽  
Flow Field ◽  
Wind Velocity ◽  
Maximum Rate ◽  
Dynamic Pressure ◽  
Jet Flow ◽  
Engine Exhaust ◽  
Jet Engine ◽  
Jet Nozzle

A combined blast fence is introduced in this paper to improve the solid blast fences and louvered ones. Experiments of the jet engine exhaust flow (hereinafter jet flow for short) field and tests of three kinds of blast fences in two positions were carried out. The results show that the pressure and temperature at the centre of the jet flow decrease gradually as the flow moves farther away from the nozzle. The pressure falls fast with the maximum rate of 41.7%. The dynamic pressure 150 m away from the nozzle could reach 58.8 Pa, with a corresponding wind velocity of 10 m/s. The temperature affected range of 40°C is 113.5×20 m. The combined blast fence not only reduces the pressure of the flow in front of it but also solves the problems that the turbulence is too strong behind the solid blast fences and the pressure is too high behind the louvered blast fences. And the pressure behind combined blast fence is less than 10 Pa. The height of the fence is related to the distance from the jet nozzle. The nearer the fence is to the nozzle, the higher it is. When it is farther from the nozzle, its height can be lowered.

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