scholarly journals Numerical Simulation and Experiment of Hydraulic Loss of Two-Stage Flap Valves

2021 ◽  
Author(s):  
Bingnan Zhou ◽  
Weigang Lu ◽  
Bo Xu ◽  
Hua Chen
Keyword(s):  
Numerical Simulation ◽  
Opening Angle ◽  
Hydraulic Loss ◽  
Two Stage ◽  
Pump Station ◽  
Simulation And Experiment ◽  
Large Opening ◽  
Relationship Of ◽  
The Relationship ◽  
Flap Valve

As a type of flap valve evolved from integral flap valve, two-stage flap valve has the advantages of large opening angle, small hydraulic loss and small impact force on the flap valve seat when the flap valve is closed. In order to analyze and study the hydraulic loss characteristics of the two-stage flap valve, this paper takes a pump station as an example. Based on theoretical analysis, combined with numerical simulation and model test, the hydraulic loss of two-stage flap valve is studied, and the relationship between hydraulic loss and pump station flow is obtained. According to the test results, the hydraulic loss of two-stage flap valve increases with the increase of flow rate under the same opening angle of flap valve. Under the same flow condition, the larger the opening angle of the flap valve is, the smaller the hydraulic loss of the two-stage flap valve is. When the opening angle of the upper flap valve is greater than 46° and the opening angle of the lower flap valve is greater than 64°, the hydraulic loss is less than 70mm and tends to be stable. The influence of hydraulic loss on the performance of pump device is gradually weakened. The relationship between hydraulic loss and flow of two-stage flap valve no longer satisfies the relationship of square under the constant opening angle. Moreover, the larger the opening angle of the two-stage flap valve is, the greater the relationship between hydraulic loss and flow is. Compared with the integral flap valve, the two-stage flap valve has better structural form and hydraulic characteristics, and has little influence on the performance of the pump device, which can provide reference for the application of the two-stage flap valve in the pump station.

Numerical Simulation of Riveting Process

2010 ◽  
Vol 34-35 ◽  
pp. 641-645
Author(s):  
Hong Shuang Zhang
Keyword(s):  
Numerical Simulation ◽  
Finite Element Method ◽  
Residual Stress ◽  
Finite Element ◽  
Process Parameters ◽  
Static Method ◽  
Riveting Process ◽  
Relationship Of ◽  
The Relationship ◽  
Element Method

In order to fully understanding the distribution of residual stress after riveting and the relationship between residual stress and riveting process parameters during riveting, Finite Element Method was used to establish a riveting model. Quasi-static method to solve the convergence difficulties was adopted in riveting process. The riveting process was divided into six stages according to the stress versus time curves. The relationship of residual stress with rivet length and rivet hole clearance were established. The results show numerical simulation is effective for riveting process and can make a construction for the practical riveting.

Stress Relaxation Behavior of Catheter Reinforced with Braid under Combined Loading for Bending and Torsion

2013 ◽  
Vol 372 ◽  
pp. 261-264 ◽  
Author(s):  
Yasuyuki Kato ◽  
Masahito Ueda
Keyword(s):  
Stress Relaxation ◽  
Principal Axis ◽  
Physical Property ◽  
Combined Loading ◽  
Two Stage ◽  
Relative Angle ◽  
Coefficient Of Viscosity ◽  
Relationship Of ◽  
The Relationship ◽  
Step Strain

The purpose of this research is to examine the physical property of the catheter, which made of soft nylon resin and is reinforced with thin stainless wires called braid. The effect of braid on the mechanical property of the catheter is revealed by investigating the relationship of the stress relaxation and the relative angle between the braid and the principal axis of stress under combined loading of bending and torsion. Inthe first place, in order to investigate the phenomenon of stress relaxation under combined loading, the experiments under single stage step strain have been carried out by changing the ratio of bending and torsion, and the relation between the coefficient of viscosity and the relative angle of the braid is revealed. In the second place, the experiment under two-stage step strain are conducted by changing the order of bending and torsion, and the effect of these loading histories on the visco-elastic properties is examined. Moreover, the numerical simulation under two-stage step strain is carried out by using the estimated coefficient of viscosity, and in this paper, the validity of this analytical model is confirmed by comparing with the experimental results.

Research on the Relationship of Flow Velocity and Particles’ Separation in Cyclone

2012 ◽  
Vol 479-481 ◽  
pp. 2529-2532
Author(s):  
Ying Zhang ◽  
Zhen Wei Zhang
Keyword(s):  
Numerical Simulation ◽  
Velocity Distribution ◽  
Flow Velocity ◽  
Structure Design ◽  
Rotating Flow ◽  
Separation Performance ◽  
Simulation Results ◽  
Relationship Of ◽  
The Relationship ◽  
Distribution Of Flow

This paper mainly focuses on the numerical simulation of flow velocity aiming to obtain the velocity distribution of flow in the cyclone. The authors took advantage of RSM turbulence model of software FLUENT to calculate the velocity distribution. Relationship between particles separation and double-layer rotating flow can be obtained based on the simulation results, which can also provide basis for the improvement of structure design and separation performance.

scholarly journals Design, Fabrication and Analysis of Threshold-Value Judging Mechanism in MEMS Safety and Arming Device

2017 ◽  
Author(s):  
Dakui Wang ◽  
Wenzhong Lou ◽  
Yue Feng ◽  
Fufu Wang
Keyword(s):  
Parametric Design ◽  
Design Method ◽  
Threshold Value ◽  
Simulation And Experiment ◽  
Design Requirements ◽  
Silicon Based ◽  
Relationship Of ◽  
The Military ◽  
The Impact ◽  
The Relationship

In order to meet the military requirements of the fuze, such as precision strike, efficient mutilates ability and low collateral damages, the microminiaturization is an inevitable trend of secure system. Based on the silicon-based MEMS S&A device designed by our term, the design principles of each module and fabrication process are introduced. The average fracture strength and Young's modulus of the silicon are 726 MPa and 175 GPa from the tensile test, respectively. From Hopkinson impact experiment, we can get the threshold-value judging mechanism being safety under the impact overload of 20526 g, and this value is much more than the standard of the drop overload 12000g; the arming value under the centrifugal overload obtained from theory, simulation and experiment is at the range of 28200 g and 32000 g, it shows that the threshold-value judging mechanism can be arming compared with the value 35951g of design principle. Therefore, the threshold-value judging mechanism can meet the design requirements of overload. Furthermore, the relationship of fracture threshold-values obtained by different theories is found out through parametric design method, as shown in Figure 14, it provides the theory evidence to the follow parametric design.

Multi-message topic dissemination probabilistic model with memory attenuation based on Social–Messages Network

2019 ◽  
Vol 30 (07) ◽  
pp. 1940011
Author(s):  
Ruiqi Yang ◽  
Dingding Han ◽  
Jianghai Qian
Keyword(s):  
Numerical Simulation ◽  
Probabilistic Model ◽  
Learning Strategy ◽  
Model Study ◽  
Social Messages ◽  
Relationship Of ◽  
The Relationship ◽  
With Memory ◽  
Spread Speed ◽  
Memory Attenuation

Current researches give priority to the diffusion of single message, but the diffusion of multi-messages at the same time in the actual network also exists. The diverse correlation of the messages will influence each other in the diffusion. It should be taken into consideration. This paper works to make a definition to the framework of Social–Messages Network. Based on it, a multi-message topic dissemination probabilistic model with memory attenuation is put forward, which introduces the correlation among messages. We adopt a simple learning strategy to gain the diverse correlation of messages. Then, the numerical simulation is utilized to analyze the model, whilst the relationship of the model parameter with the scope of the topic diffusion and the spread speed are studied and analyzed. With the related discussion data on Twitter, an empirical study is made to the model and the diffusion progress of the message is anticipated, which suggested that the anticipation is fundamentally in line with the actual data, and the estimated value of our model is closer to the reality than the classic diffusion model. Study on the topic diffusion will be conducive to the understanding and the anticipation of the multi–messages spread.

Simulation and Experimental Study on the Impact of Breadth of Back Blade on Axial Force Balance

2011 ◽  
Vol 130-134 ◽  
pp. 1568-1572
Author(s):  
Hui Wang ◽  
Jie Gang Mu ◽  
Miao Yin Su ◽  
Shui Hua Zheng ◽  
Jin Jing Zhao ◽  
...  
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Experimental Study ◽  
Axial Force ◽  
Three Dimensional ◽  
Force Balance ◽  
Simulation And Experiment ◽  
Simulation Results ◽  
The Impact ◽  
The Relationship

The paper studies the relationship between axial force and breadth of back blade by numerical simulation and experiment. On the basis of the RNG k-ε turbulence model and technology of compact local grids and regional computing, three dimensional numerical simulations to 100HZ165-250 centrifugal pump with various breadths were carried out. Through comparing and analyzing of the flow field, it can be seen that the axial force reduces with the increase of the back blade breadth. After that, the simulation results were verified by the experimental data got from different test devices, and it shows that the conclusions are reliable.

The Numerical Simulation of Air-Cooled Plate-Fin Heat Exchanger

2011 ◽  
Vol 314-316 ◽  
pp. 1472-1477 ◽  
Author(s):  
Xue Jiang ◽  
Ji Hua Bao ◽  
Yan Yu ◽  
Ming Xia Gu
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Heat Exchanger ◽  
3D Model ◽  
Fluid Velocity ◽  
Heat Transfer Characteristics ◽  
Flow And Heat Transfer ◽  
Simulation Results ◽  
Relationship Of ◽  
The Relationship

According to the periodic structure of the plate-fin heat exchanger, 3D model of the heat exchanger is established which simplifies the computation amount of the numerical simulation on flow field and temperature field. The relationship of fluid velocity, temperature, pressure drop and heat transfer coefficient is analyzed. The flow and heat transfer characteristics can be well predicted. Based on the simulation results, the conclusion makes reference to the design of plate-fin heat exchanger.

scholarly journals Numerical simulation on the leakage and diffusion of the natural gas of the underground pipeline in the soil

2021 ◽  
Vol 2083 (3) ◽  
pp. 032082
Author(s):  
Meijuan Hu ◽  
He Li ◽  
Li Chen ◽  
Ping Xie ◽  
Zheju Zhang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Natural Gas ◽  
Internal Pressure ◽  
Finite Model ◽  
Soil Environment ◽  
Leakage Model ◽  
Relationship Of ◽  
The Relationship ◽  
And Diffusion ◽  
Variation Trends

Abstract For the transportation pipeline with the diameter 1.219 m and the internal pressure 3-12 MPa, the leakage and diffusion of the natural gas of the pipeline in the soil was studied by numerical simulation. First, the finite model containing both pipeline and soil was established, and the porous media was used to simulate the real soil environment. And, the leakage amount of the natural gas was calculated at the cases with different porosities, the pressures inside the pipeline and the diameters of leakage port. Based on the classical theoretical leakage model of small hole in the air and simulation results analysis, the formula of the leakage amount was modified by the soil coefficient α to be suitable for soil environment. Then, the variation trends of the diffusion concentration of methane along different directions in the soil were analyzed by simulation, the influences of internal pressure of pipeline, the diameter of leakage and the porosity of soil were also discussed. Besides, the relationship of the safety distance with time was obtained.

Visco-Elastic Properties of Catheter Reinforced with Braids: Stress Relaxation under Two-Stage Step Strain for Different Deformation Paths

2012 ◽  
Vol 622-623 ◽  
pp. 1330-1334 ◽  
Author(s):  
Yasuyuki Kato ◽  
Show Krosawa ◽  
Masahito Ueda
Keyword(s):  
Stress Relaxation ◽  
Vascular Wall ◽  
Combined Loading ◽  
Two Stage ◽  
Relative Angle ◽  
The Subject ◽  
Relationship Of ◽  
The Relationship ◽  
Step Strain ◽  
Surgical Operations

Generally, as for the material of catheter, a soft characteristic is necessary so as not to damage vascular wall etc. On the other hand, responsivity and enough rigidity are required for the surgical operations such as myocardial infarction or cerebral infarction. Therefore, the catheter, which is made of soft nylon resin and is reinforced with thin stainless wires so called “braid”, is chosen as the subject of this study. The purpose of this study is to reveal the effect of braid on the mechanical property of the catheter by investigating the relationship of the stress relaxation and the relative angle between the braid and the principal axis of stress. Especially, in order to investigate the stress relaxation under combined loading, the experiments of two-stage step strain for tension and torsion are carried out with different deformation paths. Consequentially, the phenomenon of the stress relaxation reduces with the relative angle becomes smaller. Moreover, the numerical model under two-stage step strain is proposed in this paper, and the validity of this model is confirmed by comparing the calculated results with the experimental results.

Sign in / Sign up

Export Citation Format

Share Document