scholarly journals Hydrodynamic Analysis-Based Modeling and Experimental Verification of a New Water-Jet Thruster for an Amphibious Spherical Robot

Sensors ◽  
2019 ◽  
Vol 19 (2) ◽  
pp. 259 ◽  
Author(s):  
Xihuan Hou ◽  
Shuxiang Guo ◽  
Liwei Shi ◽  
Huiming Xing ◽  
Yu Liu ◽  
...  
Keyword(s):  
Motion Control ◽  
Axial Flow ◽  
Maximum Error ◽  
Water Jet ◽  
Experimental Results ◽  
Hydrodynamic Characteristics ◽  
Spherical Robot ◽  
Basic Framework ◽  
Oblique Flow ◽  
Simulation Results

Thrusters are the bottom actuators of the amphibious spherical robot, and play an important role in the motion control of these robots. To realize accurate motion control, a thrust model for a new water-jet thruster based on hydrodynamic analyses is proposed in this paper. First, the hydrodynamic characteristics of the new thruster were numerically analyzed using computational fluid dynamics (CFD) commercial software CFX. The moving reference frame (MRF) technique was utilized to simulate propeller rotation. In particular, the hydrodynamics of the thruster were studied not only in the axial flow but also in oblique flow. Then, the basic framework of the thrust model was built according to hydromechanics theory. Parameters in the basic framework were identified through the results of the hydrodynamic simulation. Finally, a series of relevant experiments were conducted to verify the accuracy of the thrust model. These proved that the thrust model-based simulation results agreed well with the experimental results. The maximum error between the experimental results and simulation results was only 7%, which indicates that the thrust model is precise enough to be utilized in the motion control of amphibious spherical robots.

Numerical Simulation of Pure Water Jet Machining of Al 6061-T6 With Experimental Validation

2019 ◽  
Author(s):  
Greg Pasken ◽  
Jianfeng Ma ◽  
Muhammad P. Jahan ◽  
Shuting Lei
Keyword(s):  
Pure Water ◽  
Water Jet ◽  
Experimental Results ◽  
Inlet Pressure ◽  
Orifice Diameter ◽  
Small Scale ◽  
Machining Parameters ◽  
Water Jets ◽  
Small Scales ◽  
Simulation Results

Abstract Pure water jets are not as effective as abrasive water jets for cutting hard materials at large scales. Pure water jets can have kerfs as small as 0.076 mm, which is approximately the width of a human hair. This allows for small detailed cuts on workpiece material [1]. Research into using pure water jet to machine aluminum at small scales is important, as this will allow small scale and precision machining of the work piece material. At micro scales, water jet cutting with typical abrasives is not possible because the abrasive particles are typically in the micron range which is around the size of the cut. At small scales a pure water jet is more effective than abrasive water jet machining, as special nanometer size abrasives would be needed at small scales. A pure water jet only needs the correct size orifice to conduct machining at the small scale. These are the reasons why this study uses a pure water jet to conduct small scale machining of aluminum. This study investigates the use of ABAQUS’s Smoothed Particle Hydrodynamics to simulate pure water jet machining of metals and compares the simulation results of a water jet machining of Al6061-T6 to experimental results using the same material. The simulation results compare favorably to experimental results with only 2.81% error in the width of the cut. The predictive FEM modeling is then conducted for other combinations of machining parameters (orifice diameter and inlet pressure). It is found that orifice diameter and inlet pressure have substantial influence on the width and depth of cut. The results of the study open new possibilities for machining metals using a pure water jet at the micrometer scale and at smaller scales.

Performance Prediction and Experimental Verification of Axial Flow Pump Based on CFD

2012 ◽  
Vol 152-154 ◽  
pp. 1566-1571
Author(s):  
De Sheng Zhang ◽  
Guang Jian Zhang ◽  
Wei Dong Shi ◽  
Tong Tong Li
Keyword(s):  
Flow Field ◽  
Flow Rate ◽  
Performance Prediction ◽  
Prediction Error ◽  
Axial Flow ◽  
Maximum Error ◽  
Experimental Results ◽  
Complex Flow ◽  
Axial Flow Pump ◽  
Flow Pump

The full flow field numerical simulation of the axial-flow pump model is carried out to predict the pump performance based on RNG k-ε model and SIMPLE algorithm and the method of calculating head and efficiency. The numerical results show that the head and efficiency prediction curves have a good agreement with the experimental results. In the optimal operating condition, the prediction error of head is 0.04% and the efficiency error is 0.39% which could meet the requirements of engineering applications. The prediction error based on RNG k-ε turbulence model is larger in the off-design condition owing to the complex flow field of axial-flow pump. The predicted head is lower than the experimental results in the small flow rate conditions and its maximum error is 5.12%, while is higher than the experimental data in the large flow rate conditions and its maximum error is 17.39%. The conclusions will provide the basis and reference for the performance prediction of axial-flow pumps based on CFD.

Simulation of carding condensing process

2021 ◽  
pp. 004051752098812
Author(s):  
Xixi Qian ◽  
Yuanying Shen ◽  
Qiaoli Cao ◽  
Jun Ruan ◽  
Chongwen Yu
Keyword(s):  
Experimental Results ◽  
Simulation Results ◽  
Carding Machine ◽  
The Web

A simulation describing the fiber movement during the condensation was conducted, and the effect of the condensation in the carding machine was studied. The simulation results showed that the condensation has the blending and the evening effect on the condensed sliver, which can be explained by the fiber rearrangement. Moreover, the increasing web width and the decreasing condensing length can result in a more uniform sliver. Further, the evening effect of the web width on the web was verified by experiments. The simulation results were in general agreement with the experimental results.

Validating Numerical CFD Simulations With Experimental Data for Turbulence Phenomena in Axial Flow Gas Turbine Diffusers

2009 ◽  
Author(s):  
Farrokh Zarifi-Rad ◽  
Hamid Vajihollahi ◽  
James O’Brien
Keyword(s):  
Experimental Data ◽  
Gas Turbine ◽  
Turbine Blades ◽  
Axial Flow ◽  
Experimental Results ◽  
Scale Model ◽  
Data Set ◽  
Pressure Profiles ◽  
Scale Models ◽  
Inlet Conditions

Scale models give engineers an excellent understanding of the aerodynamic behavior behind their design; nevertheless, scale models are time consuming and expensive. Therefore computer simulations such as Computational Fluid Dynamics (CFD) are an excellent alternative to scale models. One must ask the question, how close are the CFD results to the actual fluid behavior of the scale model? In order to answer this question the engineering team investigated the performance of a large industrial Gas Turbine (GT) exhaust diffuser scale model with performance predicted by commercially available CFD software. The experimental results were obtained from a 1:12 scale model of a GT exhaust diffuser with a fixed row of blades to simulate the swirl generated by the last row of turbine blades five blade configurations. This work is to validate the effect of the turbulent inlet conditions on an axial diffuser, both on the experimental front and on the numerical analysis approach. The object of this work is to bring forward a better understanding of velocity and static pressure profiles along the gas turbine diffusers and to provide an accurate experimental data set to validate the CFD prediction. For the CFD aspect, ANSYS CFX software was chosen as the solver. Two different types of mesh (hexagonal and tetrahedral) will be compared to the experimental results. It is understood that hexagonal (HEX) meshes are more time consuming and more computationally demanding, they are less prone to mesh sensitivity and have the tendancy to converge at a faster rate than the tetrahedral (TET) mesh. It was found that the HEX mesh was able to generate more consistent results and had less error than TET mesh.

scholarly journals Numerical Simulation and Experimental Study on Axial Stiffness and Stress Deformation of the Braided Corrugated Hose

2021 ◽  
Vol 11 (10) ◽  
pp. 4709
Author(s):  
Dacheng Huang ◽  
Jianrun Zhang
Keyword(s):  
Numerical Simulation ◽  
Geometric Model ◽  
Equivalent Stress ◽  
Element Model ◽  
Maximum Error ◽  
Structural Features ◽  
Axial Stiffness ◽  
Frictional Stress ◽  
Maximum Equivalent Stress ◽  
Simulation Results

To explore the mechanical properties of the braided corrugated hose, the space curve parametric equation of the braided tube is deduced, specific to the structural features of the braided tube. On this basis, the equivalent braided tube model is proposed based on the same axial stiffness in order to improve the calculational efficiency. The geometric model and the Finite Element Model of the DN25 braided corrugated hose is established. The numerical simulation results are analyzed, and the distribution of the equivalent stress and frictional stress is discussed. The maximum equivalent stress of the braided corrugated hose occurs at the braided tube, with the value of 903MPa. The maximum equivalent stress of the bellows occurs at the area in contact with the braided tube, with the value of 314MPa. The maximum frictional stress between the bellows and the braided tube is 88.46MPa. The tensile experiment of the DN25 braided corrugated hose is performed. The simulation results are in good agreement with test data, with a maximum error of 9.4%, verifying the rationality of the model. The study is helpful to the research of the axial stiffness of the braided corrugated hose and provides the base for wear and life studies on the braided corrugated hose.

The Effect of Different Turbulence Models on the Emitter Discharge by Using Computational Fluid Dynamics

2013 ◽  
Vol 662 ◽  
pp. 586-590
Author(s):  
Gang Lu ◽  
Qing Song Yan ◽  
Bai Ping Lu ◽  
Shuai Xu ◽  
Kang Li
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Flow Field ◽  
Turbulence Models ◽  
Experimental Results ◽  
Turbulent Model ◽  
Simulation Results ◽  
Rsm Model ◽  
Dynamics Method ◽  
Emitter Discharge

Four types of Super Typhoon drip emitter with trapezoidal channel were selected out for the investigation of the flow field of the channel, and the CFD (Computational Fluid Dynamics) method was applied to simulate the micro-field inside the channel. The simulation results showed that the emitter discharge of different turbulent model is 4%-14% bigger than that of the experimental results, the average discharge deviation of κ-ω and RSM model is 5, 4.5 respectively, but the solving efficiency of the κ-ω model is obviously higher than that of the RSM model.

Design of Magnetic Levitated Thrust Bearing Experiment Table

2011 ◽  
Vol 199-200 ◽  
pp. 597-602
Author(s):  
Shou Fa Liu ◽  
Zhang Jie Shi ◽  
Chun Feng Li
Keyword(s):  
Thrust Bearing ◽  
Deformation Measurement ◽  
Experimental Results ◽  
Electromagnetic Parameters ◽  
Ansys Simulation ◽  
Overall Design ◽  
Experimental Parameters ◽  
Structural Dimensions ◽  
Simulation Results

In this paper, the overall design of magnetic levitated thrust bearing experiment table was completed, of which the main experimental parameters those are electromagnetic parameters and structural dimensions were determined, in addition, the joint debugging and deformation measurement are performed. Analysis results showed that theoretical value, ANSYS simulation results and experimental results were similar, which said that it is feasible to perform stiffness check of the thrust collar on the experiment table.

The Research on Multi-Axes Automatic Motion Control Systems

2012 ◽  
Vol 459 ◽  
pp. 75-78
Author(s):  
Lian Jun Hu ◽  
Xiao Hui Zeng ◽  
Gui Xu Chen ◽  
Hong Song
Keyword(s):  
Control System ◽  
Embedded Systems ◽  
Automatic Control ◽  
Control Systems ◽  
Motion Control ◽  
Automatic Control System ◽  
Experimental Results

An automatic control system for multi-axes motions based on multi-CPU embedded systems is proposed in the paper, in order to overcome insufficiencies of available multi-axes automatic dispensing control systems. It is shown from experimental results that expected control objectives for multi-axes motions are achieved.

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