Numerical Simulation and Experimental Study of Jet Distance in Abrasive Waterjet Polishing

2012 ◽  
Vol 472-475 ◽  
pp. 2037-2042 ◽  
Author(s):  
Jia Qiang Peng ◽  
Dan Lu Song ◽  
Liang Chao Li
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Theoretical Basis ◽  
Process Research ◽  
Physical Models ◽  
Abrasive Waterjet ◽  
Workpiece Surface ◽  
Cutting Machine ◽  
Simplec Algorithm ◽  
Simulation Results

In this paper, it introduces the work principle of abrasive waterjet polishing (AWJP) and analyzes the jet distance to the influence of the AWJP under a certain pressure, with a numerical simulation and analysis to the jet distance based on jet mechanics and fluid dynamics. By establishing the physical models of the different jet distance of the AWJP and adopting the Realizable k-ε model and the SIMPLEC algorithm, it gains the jet flow field of the AWJP with different jet distance models and the distribution of turbulence intensity and pressure and velocity on the workpiece surface. The numerical simulation results of the different jet distance were analyzed and compared, according to the AWJP to the characteristic requirement of the jet. By doing the polishing experiment with a abrasive waterjet cutting machine, it verifies that the best polishing distance range of AWJP is from 10 times to 13 times of the nozzle diameter, which provides the theoretical basis for the process research of the AWPJ in the future.

scholarly journals Discussion on the Theoretical Basis for Cross-Over Method Applied to Downhole Wave Velocity Test

2021 ◽  
Vol 2021 ◽  
pp. 1-9
Author(s):  
Qing Dong ◽  
Zheng-hua Zhou ◽  
Su Jie ◽  
Bing Hao ◽  
Yuan-dong Li
Keyword(s):  
Numerical Simulation ◽  
Numerical Simulations ◽  
Wave Velocity ◽  
Theoretical Basis ◽  
Influence Factors ◽  
P Wave ◽  
Engineering Practice ◽  
S Wave ◽  
Simulation Results ◽  
The Cross

At engineering practice, the theoretical basis for the cross-over method, used to obtain shear wave arrival time in the downhole method of the wave velocity test by surface forward and backward strike, is that the polarity of P-wave keeps the same, while the polarity of S-wave transforms when the direction of strike inverted. However, the characteristics of signals recorded in tests are often found to conflict with this theoretical basis for the cross-over method, namely, the polarity of the P-wave also transforms under the action of surface forward and backward strike. Therefore, 3D finite element numerical simulations were conducted to study the validity of the theoretical basis for the cross-over method. The results show that both shear and compression waves are observed to be in 180° phase difference between horizontal signal traces, consistent with the direction of excitation generated by reversed impulse. Furthermore, numerical simulation results prove to be reliable by the analytic solution; it shows that the theoretical basis for the cross-over method applied to the downhole wave velocity test is improper. In meanwhile, numerical simulations reveal the factors (inclining excitation, geophone deflection, inclination, and background noise) that may cause the polarity of the P-wave not to reverse under surface forward and backward strike. Then, as to reduce the influence factors, we propose a method for the downhole wave velocity test under surface strike, the time difference of arrival is based between source peak and response peak, and numerical simulation results show that the S-wave velocity by this method is close to the theoretical S-wave velocity of soil.

Computational Fluid Dynamics Analysis of Two Parallel Rectangular Jets Using OpenFOAM

2016 ◽  
Author(s):  
Han Li ◽  
Huhu Wang ◽  
Yassin A. Hassan ◽  
N. K. Anand
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Turbulent Flow ◽  
Stokes Equations ◽  
Laser Doppler Anemometry ◽  
Physical Models ◽  
Shear Stresses ◽  
Turbulence Characteristic ◽  
Computational Fluid Dynamics Analysis ◽  
Simulation Results

Two or multiple parallel jets are an important shear flow that widely existing in many industrial applications. The interaction between turbulence jets enables fast and thorough mixing of two fluids. The mixing feature of parallel jets has many engineering applications, such as, in Generation IV conceptual nuclear reactors, the coolants merge in upper or lower plenum after passing through the reactor core. While study of parallel jets mixing phenomenon, numerical experiments such as Computational Fluid Dynamics (CFD) simulations are extensively incorporated. Validation of varied turbulent models is of importance to make sure that the numerical results could be trusted and served as a guideline further design purpose. Many commercial CFD packages in the market such as FLUENT and Star CCM+ can provide the ability to simulate turbulent flow with predefined turbulence model, however, such commercial solvers may lack the flexibility that allow users build their own models for R&D purpose. The existing solvers in OpenFOAM are developed to fulfill both academic and industrial needs by achieving large-scale computational capability with a variety of physical models. Moreover, as an open source CFD toolbox, OpenFOAM grants users full control of the source code with complete freedom of customization. The purpose of this study is to perform CFD simulation using OpenFOAM for two submerged parallel jets issuing from two rectangular channels. Fully hexahedron multi-density mesh is generated using blockMesh utility to ensure velocity gradients are properly evaluated. A generalized-multi-grid solver is used to enhance convergence. Based on Reynolds-Averaged Navier-Stokes Equations (RANS), the realizable k-ε and k-ε shear stress transport (SST) are selected to model turbulent flow. Steady state Finite Volume solver simpleFoam is used to perform the simulation. In addition, data from experiments run in Thermal-Hydraulic Lab at Texas A&M University using particle image velocity (PIV) and Laser Doppler Anemometry (LDA) methods are considered in order to compare and validate simulation results. A number of turbulence characteristic such as mean velocities, turbulent intensities, z-component vorticity were compared with experiments. It was found that for stream-wise mean velocity profile as well as shear stresses, the realizable k-ε model exhibits a good agreement with experimental data. However, velocity fluctuation and turbulence intensities, simulation results showed a certain discrepancy.

Numerical Simulation and Process Research for Cylindrical Drawing

2010 ◽  
Vol 20-23 ◽  
pp. 1405-1408 ◽  
Author(s):  
Wei Hua Kuang ◽  
Qun Liu
Keyword(s):  
Numerical Simulation ◽  
Finite Element ◽  
Finite Element Model ◽  
Element Model ◽  
Process Research ◽  
Die Design ◽  
Drawing Process ◽  
3D Finite Element ◽  
Simulation Results ◽  
Distribution Of Stress

Drawing process is an important technology in shaping products. In the paper, the geometric surfaces of tools and sheet were modeled by Pro/E software, and a 3D finite element model of the cylindrical drawing process was developed by DYNAFORM. Numerical simulation results showed the distribution of stress, strain and thickness. FLD showed no material was in crack area and risk crack area. The drawing process could be successfully completed in one stroke. The simulation results were helpful for the die design.

Effect of Blade Inclining Angle on Internal Characteristic of Hydraulic Retarder

2014 ◽  
Vol 664 ◽  
pp. 89-93
Author(s):  
Hui Xiao ◽  
Ya Xu Chu
Keyword(s):  
Numerical Simulation ◽  
Moving Mesh ◽  
Moving Mesh Method ◽  
Internal Characteristic ◽  
Mesh Method ◽  
Braking Torque ◽  
Simplec Algorithm ◽  
Simulation Results ◽  
Hydraulic Retarder ◽  
Rng Turbulence Model

Based on CFD software platform the numerical simulation of internal characteristic of hydraulic retarder was performed by moving mesh method with the RNG turbulence model and the SIMPLEC algorithm simultaneously, the internal characteristics of velocity and pressure distribution were analyzed through the numerical simulation and post-processing. Comparing the calculation braking torque with the simulation results. The result shows that the model under 42°vane degree has the biggest impact.

Numerical and Experimental Study on a Honeycomb Ceramic Monolith

2012 ◽  
Vol 532-533 ◽  
pp. 431-435
Author(s):  
Chong Zhi Mao ◽  
Qian Jian Guo ◽  
Lei He
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Experimental Study ◽  
Computational Fluid Dynamics ◽  
Flue Gas ◽  
Regenerative Process ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Honeycomb Ceramic ◽  
Oxidation Reactor

Honeycomb ceramic is the key component of the regenerative system. The numerical simulation was performed using FLUENT, a commercial computational fluid dynamics (CFD) code, to compare simulation results to the test data. The regenerative process of a honeycomb ceramic regenerator was simulated under different conditions. Experiments were carried out on honeycomb regenerators that are contained in a methane oxidation reactor. The calculated temperatures of flue gas inlet were compared with the ones measured. The tendency of the temperature is the same as the experiment.

Experimental and numerical study of vortex gripper with a diversion body

2011 ◽  
Vol 226 (6) ◽  
pp. 1526-1534 ◽  
Author(s):  
Q Wu ◽  
Q Ye ◽  
G X Meng
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Swirling Flow ◽  
Numerical Study ◽  
Reynolds Stress Model ◽  
Stress Model ◽  
Lifting Force ◽  
Handling Device ◽  
Simulation Results

This article introduces a new vortex gripper with a diversion body. Vortex gripper, as a pneumatic non-contact handling device, can generate lifting force to hold a workpiece without any contact. In order to predict the characteristics of this new vortex gripper, including pressure distribution on the upper surface of the workpiece, lifting force, supporting stiffness, and flowrate, a computational fluid dynamics study has been carried out. In the vortex cup, air swirling flow is a complex turbulent one; so Reynolds stress model (RSM) was used to describe internal air swirling flow. In addition, an experiment was carried out to study the characteristics of the vortex gripper. When compared with the experimental results, the reliability of numerical simulation results by RSM was verified. The vortex gripper with a diversion body could generate greater lifting force when compared with those designed by Xin et al. with the same air consumption. Therefore, the efficiency of the vortex gripper is improved.

Numerical Simulation of Flow Field of Inflation Pressure for Large Complex Sulfide Mineral of Low-Tin Flotation Machine

2013 ◽  
Vol 341-342 ◽  
pp. 333-336
Author(s):  
Ming Zhen Hu ◽  
Bo Zeng Wu ◽  
Jin Quan Chen ◽  
Ji Shu Zeng
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Flow Field ◽  
Sulfide Mineral ◽  
Inflation Pressure ◽  
Flotation Machine ◽  
Complex Sulfide ◽  
Flow Field Characteristics ◽  
Machine Simulation ◽  
Simulation Results

For flotation characteristics of complex sulfide mineral of low-tin in Guangxi Dachang mine, fluid dynamics software FLUENT was applied to simulate the turbulence intensity of slurry fluid in flotation machine at different inflation pressures. The effect of flow field characteristics was gotten for flotation machine. Simulation results show that the best inflation pressure was 120000 Pa.

Numerical Simulation of the Inner Flow Field and the Optimal Design of Hema-Type ATY Nozzle Based on Fluent

2013 ◽  
Vol 634-638 ◽  
pp. 3774-3777
Author(s):  
Min Hua Zhang ◽  
Hong Mei Zheng ◽  
Cui Liu ◽  
Yin Hu Qu ◽  
Tao Liang ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Optimal Design ◽  
Flow Field ◽  
Flow Fields ◽  
Fluent Software ◽  
Simulation Results

the inner flow fields of twelve Hema-type ATY nozzles which have different structure and parameters are simulated by the Fluent software, which is based on the CFD (Computational Fluid Dynamics) theory.Then the simulation results are analyzed，through wich the best designed nozzle is determined.

Computational Fluid Dynamics Simulation about Comparison of Different Forms of Return Air in a Small Cold Store

2012 ◽  
Vol 516-517 ◽  
pp. 1133-1138 ◽  
Author(s):  
Yi Tang ◽  
Jing Xie ◽  
Jin Feng Wang ◽  
Chen Miao ◽  
Yi Zheng
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Finite Volume Methods ◽  
Dynamics Simulation ◽  
Wall Function ◽  
Computational Fluid Dynamics Simulation ◽  
Cold Store ◽  
Simulation Results

The quantity of the cold store in our country has been rapidly rising since the 1990s, however, the flow field in the cold store is difficult to obtain accurately by experiments. With reference to the experiences in previous numerical simulations in this paper, CFD is used for analyzing two forms of return air in the cold store with the Finite Volume Methods and the SIMPLE Revised. As a result, Combining with the non-equilibrium wall function, it is found that taking the way of return air on both sides of the fan is more reasonable and the cooling consumption of the empty cold store can be saved before the products enter the cold store. Furthermore, the numerical simulation results can provide reference for choosing fans in the small cold store.

Numerical Simulation of Cross-Ventilation in Buildings Affected by Surrounding Buildings with Different Separation Distances

2013 ◽  
Vol 353-356 ◽  
pp. 2993-2996 ◽  
Author(s):  
Tao Tao Shui ◽  
Jing Liu ◽  
Fei Ma
Keyword(s):  
Fluid Dynamics ◽  
Numerical Simulation ◽  
Computational Fluid Dynamics ◽  
Street Canyon ◽  
Natural Ventilation ◽  
Flow Characteristics ◽  
Airflow Rate ◽  
Computational Fluid Dynamics Cfd ◽  
Simulation Results ◽  
Des Model

In order to investigate natural cross-ventilation in buildings, computational fluid dynamics (CFD) with the DES model is applied. The aim of this paper is to investigate the influence of surrounding buildings on natural ventilation in target building under different separation distances. The simulation results indicate that surrounding buildings has a significant impact on airflow structure and airflow rate of the target building. The flow characteristics in target building is determined by the flow regime in street canyon.

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