Influence of Pressure Fluctuation on Reflux Valve in a Self-Priming Pump With Outer Recirculation

2010 ◽  
Author(s):  
Hong Li ◽  
Zhenhua Shen ◽  
Jianrui Liu ◽  
Chao Wang
Keyword(s):  
Pressure Fluctuation ◽  
Pressure Difference ◽  
Pressure Fluctuations ◽  
Three Dimensional ◽  
Pressure Sensors ◽  
Element Analysis ◽  
Turbulence Flow ◽  
The Finite Element Analysis ◽  
Priming Process ◽  
The Stability

The pressure fluctuation caused by impeller-volute interaction is one of the factors which affect the stability of self-priming pump with outer recirculation. Based on the RNG k–ε turbulence model, three-dimensional unsteady turbulence flow in a self-priming pump was simulated in this paper. Pressure fluctuations were obtained at 26 monitor points distributed at eight sections of the volute and on the reflux valve, and the influence on the valve was analyzed. The CFD results show that the main frequency of monitor points is blade passing frequency, and the pressure difference between maximum and average is minimal at the fifth section, which is 1.3%∼2.4%. Using pressure sensors and LabVIEW system, the pressures at third, fifth and seventh sections were tested. The experimental results show that pressure fluctuation layouts are similar as those from CFD, and the pressure difference at the fifth section is 4%, also the minimum. The position also is found with minimal influence on reflux valve. Reflux hole should be placed at 200° ∼ 220° from the tongue along the direction of the impeller rotation. Further, according to the CFD results, the Finite Element Analysis (FEA) of the reflux valve was carried out. FEA shows that the valve can close the reflux hole completely after self-priming process, which gets a good hydraulic performance when the pump runs normally.

Finite Element Analysis of Nonuniformity of Tires with Imperfections5

2007 ◽  
Vol 35 (3) ◽  
pp. 226-238 ◽  
Author(s):  
K. M. Jeong ◽  
K. W. Kim ◽  
H. G. Beom ◽  
J. U. Park
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Element Model ◽  
Radial Force ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Force Variation ◽  
Three Dimensional Finite Element

Abstract The effects of variations in stiffness and geometry on the nonuniformity of tires are investigated by using the finite element analysis. In order to evaluate tire uniformity, a three-dimensional finite element model of the tire with imperfections is developed. This paper considers how imperfections, such as variations in stiffness or geometry and run-out, contribute to detrimental effects on tire nonuniformity. It is found that the radial force variation of a tire with imperfections depends strongly on the geometrical variations of the tire.

Modeling and experimental verification on directivity of an electret cell array loudspeaker

2012 ◽  
Vol 24 (3) ◽  
pp. 326-333 ◽  
Author(s):  
Yu-Chi Chen ◽  
Wen-Ching Ko ◽  
Han-Lung Chen ◽  
Hsu-Ching Liao ◽  
Wen-Jong Wu ◽  
...  
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Three Dimensional ◽  
Digital Control System ◽  
Analysis Model ◽  
Cell Array ◽  
Element Analysis ◽  
Finite Element Analysis Model ◽  
The Finite Element Analysis ◽  
Directivity Characteristics

We propose a model to give us a method to investigate the characteristic three-dimensional directivity in an arbitrarily configured flexible electret-based loudspeaker. In recent years, novel electret loudspeakers have attracted much interest due to their being lightweight, paper thin, and possessing excellent mid- to high-frequency responses. Increasing or decreasing the directivity of an electret loudspeaker makes it excellent for adoption to many applications, especially for directing sound to a particular area or specific audio location. Herein, we detail a novel electret loudspeaker that possesses various directivities and is based on various structures of spacers instead of having to use multichannel amplifiers and a complicated digital control system. In order to study the directivity of an electret loudspeaker based on an array structure which can be adopted for various applications, the horizontal and vertical polar directivity characteristics as a function of frequency were simulated by a finite-element analysis model. To validate the finite-element analysis model, the beam pattern of the electret loudspeaker was measured in an anechoic room. Both the simulated and experimental results are detailed in this article to validate the various assertions related to the directivity of electret cell-based smart speakers.

scholarly journals Flexural-Torsional Vibration of Thin-Walled Beams Subjected to Combined Initial Axial Load and End Bending Moment: Application to the Design of Saw Tooth Blades

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Van Binh Phung ◽  
Anh Tuan Nguyen ◽  
Hoang Minh Dang ◽  
Thanh-Phong Dao ◽  
V. N. Duc
Keyword(s):  
Boundary Conditions ◽  
Axial Load ◽  
Stability Boundary ◽  
Bending Moment ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Rayleigh Method ◽  
Thin Walled ◽  
The Stability ◽  
Fixed End

The present paper analyzes the vibration issue of thin-walled beams under combined initial axial load and end moment in two cases with different boundary conditions, specifically the simply supported-end and the laterally fixed-end boundary conditions. The analytical expressions for the first natural frequencies of thin-walled beams were derived by two methods that are a method based on the existence of the roots theorem of differential equation systems and the Rayleigh method. In particular, the stability boundary of a beam can be determined directly from its first natural frequency expression. The analytical results are in good agreement with those from the finite element analysis software ANSYS Mechanical APDL. The research results obtained here are useful for those creating tooth blade designs of innovative frame saw machines.

scholarly journals Effect of Ring Material and Diameter on Orthopedic Implant Stability: External Fixation in Femur Bone

2018 ◽  
Vol 7 (4.26) ◽  
pp. 190 ◽  
Author(s):  
Nur Fatin Izzati Ibrahim ◽  
Ruslizam Daud ◽  
Muhammad Khairul Ali Hassan ◽  
Noor Ali Hassan ◽  
Noor Alia Md Zain ◽  
...  
Keyword(s):  
External Fixation ◽  
Von Mises Stress ◽  
Axial Stiffness ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Ring Diameter ◽  
The Stability ◽  
Von Mises ◽  
Fixation Frame ◽  
Ring Material

Axial stiffness is the most important factor in stability. It is known that any changes in the diameter of any components of the frame will either increase or decrease the axial stiffness of the fixation. The model of implant and bone will be variety as the variables changes. Current studies states that ring stability are one of the most important factors in ensuring fractured bones to have a successful re-union. In circular external fixation, the stability of the pin-bone interaction is influenced by the stability of the fixation frame where the major component is the rings. The objective is to study the finite element analysis (FEA) of the external fixator assembled in human diaphysis under compression force with different materials of the exoskeleton which are stainless steel, titanium alloy, magnesium alloy and carbon fiber. The results obtained show the mechanical strength of each material where it will be used to compare the value of von-Mises stress, stiffness and total deformation to acquire the best suitable ring diameter and material. Based on the result, as the diameter of the ring increases, the stiffness of the ring will be decreased. 

scholarly journals Evaluation of the Effects of the Chincup Appliance on the Craniofacial Structures by the Finite Element Analysis

2017 ◽  
Vol 7 ◽  
pp. 219-223
Author(s):  
Beril Demir Karamanli ◽  
Hülya Kılıçoğlu ◽  
Armagan Fatih Karamanli
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Fe Model ◽  
Analysis Method ◽  
Class Iii ◽  
Element Analysis ◽  
The Finite Element Analysis ◽  
Dimensional Finite Element ◽  
Three Dimensional Finite Element ◽  
Clinical Changes

Aims The aim of this study is to evaluate the effects of the chincup appliance used in the treatment of Class III malocclusions, not only on the mandible or temporomandibular joint (TMJ) but also on all the craniofacial structures. Materials and Methods Chincup simulation was performed on a three-dimensional finite element (FE) model. 1000 g (500 g per side) force was applied in the direction of chin-condyle head. Nonlinear FE analysis was used as the numerical analysis method. Results By the application of chincup, stresses were distributed not only on TMJ or mandible but also on the circummaxillary sutures and other craniofacial structures. Conclusions Clinical changes obtained by chincup treatment in Class III malocclusions are not limited by only mandible. It was seen that also further structures were affected.

Design and Analysis of a Tow Truck’s Lifting Organ

2014 ◽  
Vol 644-650 ◽  
pp. 137-141
Author(s):  
Guo Sheng Zhang ◽  
Wei Zhou ◽  
Ye Chen ◽  
Jian Qiang Gong
Keyword(s):  
Mechanical Design ◽  
Three Dimensional ◽  
Operation Condition ◽  
Element Analysis ◽  
Vehicle Accidents ◽  
Local Strength ◽  
The Finite Element Analysis ◽  
Design Software ◽  
Mechanics Characteristics ◽  
Game Type

According to the super large or heavy vehicle accidents existing wrecker cannot complete the wrecker rescue mission independent problems, puts forward the design of a practical game type crane wrecker. The hoisting mechanism as the research object, the traditional mechanical method is designed and calculated, then the three-dimensional entity model using 3D mechanical design software Solidworks, and imported into the finite element analysis software ANSYS to analyze the static mechanics characteristics of the structure, to improve the local strength of short position. On this basis, a lifting test vehicle prototype, rated load operation and overload operation condition test, and measure its subsidence. With the analysis of the experiment results, show that the design truck lifting organ can meet the demand of the technology.

Structural Stability Evaluation for Lifting Lug Design of Large Marine Engine by Finite Element Analysis

2007 ◽  
Vol 353-358 ◽  
pp. 2855-2859
Author(s):  
W.C. Lee ◽  
Chae Sil Kim ◽  
J.B. Na ◽  
D.H. Lee ◽  
S.Y. Cho ◽  
...  
Keyword(s):  
Finite Element ◽  
Three Dimensional ◽  
Design Procedure ◽  
Steel Structures ◽  
Stability Evaluation ◽  
Element Analysis ◽  
Marine Engines ◽  
Dimensional Finite Element ◽  
The Stability ◽  
Three Dimensional Finite Element

Since most marine engines are generally very huge and heavy, it is required to keep safety from accidents in dealing them. Several types of lifting lugs have been used to assemble hundred ton–large steel structures and carry the assembled engines. Recently a few crashes have been occurred in carrying engines due to breaking down the lugs. Although the stability evaluation of the lifting lug has therefore been very important for safety, systematic design procedure of the lugs, which includes the structural analysis considering stability, has few reported. This paper describes the three dimensional finite element structural modeling for a lifting lug, the studies for determining the reasonable loading and boundary conditions, and the stability evaluation with the results of structural analyses. It should be very helpful for designing the other types of lifting lugs with safety.

The Cavitation-Induced Pressure Fluctuations in a Mixed-Flow Pump under Impeller Inflow Distortion

Machines ◽  
2021 ◽  
Vol 9 (12) ◽  
pp. 326
Author(s):  
Huiyan Zhang ◽  
Fan Meng ◽  
Yunhao Zheng ◽  
Yanjun Li
Keyword(s):  
Frequency Domain ◽  
Pressure Fluctuation ◽  
Dynamic Pressure ◽  
Pressure Fluctuations ◽  
Pressure Sensors ◽  
Mixed Flow ◽  
Guide Vanes ◽  
Time Frequency ◽  
Critical Cavitation ◽  
Flow Pump

To reduce cavitation-induced pressure fluctuations in a mixed-flow pump under impeller inflow distortion, the dynamic pressure signal at different monitoring points of a mixed-flow pump with a dustpan-shaped inlet conduit under normal and critical cavitation conditions was collected using high-precision digital pressure sensors. Firstly, the nonuniformity of the impeller inflow caused by inlet conduit shape was characterized by the time–frequency-domain spectra and statistical characteristics of pressure fluctuation at four monitoring points (P4–P7) circumferentially distributed at the outlet of the inlet conduit. Then, the cavity distribution on the blade surface was captured by a stroboscope. Lastly, the characteristics of cavitation-induced pressure fluctuation were obtained by analyzing the time–frequency-domain spectra and statistical characteristic values of dynamic pressure signals at the impeller inlet (P1), guide vanes inlet (P2), and guide vanes outlet (P3). The results show that the flow distribution of impeller inflow is asymmetric. The pav values at P4 and P6 were the smallest and largest, respectively. Compared with normal conditions, the impeller inlet pressure is lower under critical cavitation conditions, which leads to low pav, pp-p and a main frequency amplitude at P1. In addition, the cavity covered the whole suction side under H = 13.6 m and 15.5 m, which led the pp-p and dominant frequency amplitude of pressure fluctuation at P2 and P3 under critical cavitation to be higher than that under normal conditions.

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