Modelling of Hydraulic Seals Using an Axisymmetric Volume of Fluid Method (VOF)

2013 ◽  
Author(s):  
Hans-Christian Mathews ◽  
Hervé Morvan ◽  
Davide Peduto ◽  
Yi Wang ◽  
Colin Young ◽  
...  
Keyword(s):  
Design Method ◽  
Analytical Calculation ◽  
Volume Of Fluid ◽  
Numerical Results ◽  
Dimensionless Number ◽  
Maximum Pressure ◽  
Oil Consumption ◽  
Fluid Properties ◽  
Calculation Results ◽  
Aero Engines

Hydraulic seals are used in aero engines because of their excellent sealing properties. Sealing of oil inside bearing chambers is extremely important as leakage of oil into internal spaces of the engine increases the oil consumption and can result in undesirable effects, ranging from cosmetic to mechanical. A robust dimensioning of the seal is therefore essential. However, the maximum pressure capacity of the hydraulic seal is not always determined accurately enough with many of the existing design approaches, so a high safety factor must be used. It is desirable to keep improving the accuracy of these methods, in particular to handle ever larger pressure differences. A new dimensionless design method is therefore introduced here to improve the determination of the maximum pressure capacity. This paper reports on a numerical CFD investigation using an axisymmetric Volume-of-Fluid (VOF) method building on the work of Young and Chew [1]. The numerical results are validated with the results of a two-shaft test rig, alongside analytical calculation results. Additionally, a parametric study based on CFD simulations is performed to identify dominant influence quantities. The parameters include the fluid properties of oil, the shaft speeds and the geometry parameters of the seal. Employing a data reduction approach, a new dimensionless number is introduced which allows the presentation of experimental and numerical results of the hydraulic seal in a dimensionless form. Based on this representation, a correlation is proposed, which shows a very promising trend. This validated CFD investigation and subsequent correlation introduced here show significant potential for the dimensionless description of hydraulic seals and their maximum pressure capacity.

scholarly journals Novel Robust Design Method of Multilayer Optical Coatings

ISRN Optics ◽  
2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Suyong Wu ◽  
Xingwu Long ◽  
Kaiyong Yang
Keyword(s):  
Robust Design ◽  
Optimization Design ◽  
Design Method ◽  
Analytical Calculation ◽  
Design Procedure ◽  
Deposition Process ◽  
Practical Significance ◽  
Optical Coatings ◽  
Optical Films ◽  
Robust Design Method

We present a novel fast robust design method of multilayer optical coatings. The sensitivity of optical films to production errors is controlled in the whole optimization design procedure. We derive an analytical calculation model for fast robust design of multilayer optical coatings. We demonstrate its effectiveness by successful application of the robust design method to a neutral beam splitter. It is showed that the novel robust design method owns an inherent fast computation characteristic and the designed film is insensitive to the monitoring thickness errors in deposition process. This method is especially of practical significance to improve the mass production yields and repetitive production of high-quality optical coatings.

Load Calculation and Life Prediction for Auto Water Pump Bearing

2012 ◽  
Vol 134 (4) ◽  
Author(s):  
Zhengmei Li ◽  
Qiong Zhou ◽  
Jianping Tang ◽  
Jianwen Wang ◽  
Qi An
Keyword(s):  
Load Distribution ◽  
Normal Load ◽  
Analytical Calculation ◽  
Engineering Application ◽  
Water Pump ◽  
Bearing Load ◽  
Calculation Results ◽  
Bearing Design ◽  
Bearing Loads

Taking the water pump bearing with one roller row (WR)-type auto water pump bearing as a research sample, an analytical calculation method is developed to improve the accuracy and efficiency of the current calculations for the bearing loads and life in engineering application. Considering the misalignment due to the deflection of the bearing spindle, the bearing internal loads and deformations under the action of the complicated external space loads are obtained. The bearing fatigue life including the lives of the rollers and the balls is also calculated with considering the non-normal load distribution caused by the spindle deflection and the roller tilt. The bearing load and life calculation results are compared with those calculated by the traditional method in which the deflection of the bearing spindle and the roller tilt are ignored. The effects of the bearing spindle deflection on the load distribution and the life of the auto water pump bearing are analyzed and discussed. The life decrease in the auto water pump bearing is significant due to the deflection of the bearing spindle and it is recommended to give more attention to this deflection for the high quality of the bearing design and calculation.

scholarly journals Manipulate Vibration Propagation by Anisotropic Honeycomb Structure

2018 ◽  
Vol 175 ◽  
pp. 03040
Author(s):  
Xiang Chen ◽  
Xiao-ming Wang ◽  
Yu-lin Mei
Keyword(s):  
Design Method ◽  
Honeycomb Structure ◽  
Homogenization Method ◽  
Unit Cell ◽  
Field Analysis ◽  
Acoustic Wave Propagation ◽  
Asymptotic Homogenization ◽  
Fluid Properties ◽  
Asymptotic Homogenization Method ◽  
New Type

As a new type of acoustic metamaterial, the pentamode material has extensive application prospect in controlling acoustic wave propagation because of its fluid properties. Firstly, a kind of pentamode material unit cell is designed, which is a two-dimensional honeycomb truss structure. Then, the asymptotic homogenization method is used to calculate static parameters of the unit cell, and also the influence of the geometric parameters and material composition of the unit cell on its mechanical properties is studied. Besides, based on transformation acoustics and the design method of the cylindrical cloak proposed by Norris, an acoustic cloak with isotropic density and gradient elastic modulus is constructed by periodically assembling the unit cell to guide the wave to bypass obstacles. Finally, the full displacement field analysis is carried out to prove the stealth effect of the acoustic cloak.

A Novel Radial Telescopic Tire Building Drum and its Kinematics Design

2012 ◽  
Vol 215-216 ◽  
pp. 207-211
Author(s):  
Yun Long Wang ◽  
Lei Zhang ◽  
Yu Hu Yang
Keyword(s):  
Design Method ◽  
Maximum Pressure ◽  
Interference Condition ◽  
Radial Tire ◽  
Mechanical Structure ◽  
Pressure Angle ◽  
External Shell ◽  
Contraction Ratio ◽  
Force Transfer ◽  
Tire Production

A novel radial telescopic tire building drum is proposed to meet the radial tire production requirements. After the discussion of the mechanical structure and transmission principle of this mechanism, the kinematics equations together with the formulas of contraction ratio and pressure angle are established. In order to optimize the characteristics of force-transfer, when taking the interference condition into consideration, a kinematics design method of this novel radial telescopic building drum is proposed, which can obtain the minimal value of mechanism maximum pressure angle and satisfy the demand of contraction ratio. The most important feature of this building drum is that the external shell is driven by the internal shell. Designer can derivative more design schemes by applying this transmission principle.

Design Method of Self-Loading Device of the Side-Crane Used for Container

2012 ◽  
Vol 466-467 ◽  
pp. 951-955
Author(s):  
Jun Qing Zhan ◽  
Xiao Mei Feng ◽  
Li Shun Li ◽  
Xiang De Meng
Keyword(s):  
Mathematical Model ◽  
Structural Design ◽  
Design Method ◽  
The Self ◽  
Design Calculation ◽  
Force Analysis ◽  
Loading Device ◽  
Calculation Results ◽  
The Mathematical Model ◽  
Flat Ground

The self-loading device used for side-crane is put forward. Its structure is presented. Based on the force analysis when the side-crane works at flat ground, the mathematical model is established when the crane working at uneven ground. And the design calculation is performed. The self-loading device’s optimal design is accomplished. Based on the above calculation results, the self-loading prototype is manufactured. And the design method can be adopted to the similar equipment’s structural design.

Lattice Light Steel Frame System and Application

2011 ◽  
Vol 105-107 ◽  
pp. 1110-1113
Author(s):  
Bo Ding ◽  
Huan Qing Jiang ◽  
Hong Xia Wan ◽  
Feng Zhang
Keyword(s):  
High Speed ◽  
Design Method ◽  
Calculation Model ◽  
Steel Frame ◽  
Calculation Results ◽  
Frame System ◽  
Practical Engineering ◽  
Steel Consumption ◽  
New Type ◽  
New System

Lattice light steel frame is a new type of structural system, combining general steel framework which is composed of lattice column and lattice beam with lattice light steel keel of the partitions and floors, the system takes full advantages of both structural systems, with high speed construction, less steel consumption, good earthquake-resistance etc., and possesses good prospects. The paper describes the system construction approach and the characteristics of lattice light steel frame system, and provides a project example of a villa. The design method and calculation model of the project are presented. Calculation results meet the specifications’ requirements, proving the new system can be applied to practical engineering. The paper gives guidance for application and research of this new system.

Rock Floor Pressure Analysis of Hydraulic Support

2013 ◽  
Vol 389 ◽  
pp. 1058-1061
Author(s):  
Zhi Wang ◽  
He Ping Ni
Keyword(s):  
Pressure Distribution ◽  
Hard Rock ◽  
Beam Theory ◽  
Base Plate ◽  
Maximum Pressure ◽  
Distribution Law ◽  
Hydraulic Support ◽  
Calculation Results ◽  
Elastic Foundation Beam ◽  
Selection Of

According to the plastic floor assumptions, the floor pressure distribution law was obtained based on plane force analysis of hydraulic support. In order to compare the floor pressure on the elastic floor and plastic floor, Elastic foundation beam theory was introduced to the calculation of the floor pressure. The results show that the pressure distribution is changed with the changing of the subgrade coefficient. The pressure is trapezoidal distributed when the floor is relatively soft and the plastic floor assumptions is reasonable. In a relatively hard rock floor, the maximum pressure appear near the column nest which is very different from the calculation results based on the plastic base plate assumptions. It is suggested that the soft and the hard rock floor should be treated differently during the design and selection of hydraulic support. .

CFD Simulation of an Aeroengine Bearing Chamber Using an Enhanced Volume of Fluid (VOF) Method: An Evaluation Using Adaptive Meshing

2014 ◽  
Author(s):  
Alexandre Crouchez-Pillot ◽  
Hervé P. Morvan
Keyword(s):  
Cfd Simulation ◽  
Adaptive Mesh ◽  
Volume Of Fluid ◽  
Vof Method ◽  
Physical Models ◽  
Adaptive Meshing ◽  
Displacement Pump ◽  
Aero Engines ◽  
Set Up ◽  
Cooling And Lubrication

In aero engines, the rotating shafts are supported by a set of bearings, which are enclosed in bearing chambers. Cooling and lubrication oil escapes from the bearings and these chambers are designed to capture and recycle it. A good understanding of the oil behaviour inside bearing chambers is therefore desirable in order to limit the oil volume involved and minimize transmission losses whilst managing the engine core heat in the best possible manner. This study is focused on the simulation of the oil behaviour inside such a chamber and special attention is given to the so-called KIT bearing chamber. The oil phase in the chamber can take different forms e.g. sprays, droplets, thin films or a combination of those. Assuming the oil we want to track remains dominantly as a film and large droplets/filaments, the Volume of Fluid (VOF) method is used in order to track the oil and the oil/air interface in the chamber, hereby investigating the feasibility and merits of such an approach and extending the earlier work carried out by the authors and colleagues. An Enhanced VOF approach coupled with level-set is used here unless stated otherwise. The simulated pump outlet condition, proposed by the University of Nottingham, is also employed in this study, to replicate an engine displacement pump. Since the use of VOF requires a refined mesh in the oil region, an adaptive mesh approach based on the volume of fluid gradient is developed and validated to control the total cell count for some of the cases reported here and limit simulation costs. The Adaptive Mesh Approach (AMA) can allow a better resolution of critical interfaces, better compute the oil break-up (within the limitation of the physical models used) and then track the droplets and filaments. Therefore, not only the CPU time cost might be reduced compared to a fixed mesh approach but significant physical aspects of the problem should be better accounted for. In order to inform the set up and parameters used with this method, and appraise its value for the proposed application, the experimental study of Fabre is used before the approach is applied to the KIT chamber. Good insight is obtained in terms of run time acceleration for such problem when combining the proposed VOF setup with adaptive meshing. Key set up parameters are quantified. The simulations carried out with the proposed set up are proving to be fairly robust and stable. Qualitative (physical) evidence is also encouraging and confirms the value of such an approach to the study of aeroengine bearing chambers.

scholarly journals Out-of-Plane Deformation Analysis of the Thin-Walled Closed Curved Box Girder under the Temperature Gradient

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Zeying Yang ◽  
Chenghe Wang ◽  
Yinglin Sun ◽  
Yangyudong Liu ◽  
Zhengquan Cheng ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Plane Deformation ◽  
Minimum Energy ◽  
Analytical Calculation ◽  
Temperature Deformation ◽  
Curve Beam ◽  
Box Girder ◽  
Out Of Plane ◽  
Calculation Results ◽  
Thin Walled

For calculating the thin-walled closed curved box girder caused by the temperature gradient of the internal force and displacement, based on the fundamental differential equation of the curve beam and the principle of minimum energy, set a reverse statically indeterminate simply supported curve beam as the basic structure, consider the warping effect of the closed curve box girder, and put forward a kind of plane curve beam temperature deformation simple analytical calculation method. Compared with the finite element calculation results, the relative error of the analytical calculation results is less than 5%. It is concluded that the analytical method has sufficient accuracy in calculating the out-of-plane deformation of the thin-walled closed curved box girder under the temperature gradient.

scholarly journals Analytical description of the specific electric conductivity of halogenides KHal melts and its calculation for the KAt melt

2019 ◽  
Vol 58 (6) ◽  
pp. 138-145
Author(s):  
Ivan K. Garkushin ◽  
◽  
Olga V. Lavrenteva ◽  
Yana A. Andreeva ◽  
Karina R. Gilmanova ◽  
...  
Keyword(s):  
Least Squares Method ◽  
Specific Conductivity ◽  
Analytical Calculation ◽  
Analytical Description ◽  
Order Number ◽  
Specific Electric Conductivity ◽  
Alkaline Earth Elements ◽  
Straight Line ◽  
Electronegativity Difference ◽  
Calculation Results

In this paper, the analytical description of the specific conductivity of the potassium halogenides melts KHal (Hal – F, Cl, Br, I) is presented. The analitical description is provided on dependence of the specific conductivity on the halogen order number ӕ = f(Z), the ionic radius of halogen-ion ӕ = f(r), the ionic potential ӕ = f(1/r), the electronegativity difference ӕ = f(∆χ) ((∆χ = χ (Hal) – χ(K)). The interrelation of a reduced property with an order number ӕ/Z = f(Z) is considered. According to the obtained analytical dependencies, the calculation of the value of the potassium astatide specific conductivity is given for temperatures above the melting point on 5, 10, 50, 75, 100, 150 и 200°, in literature Information for KAt absent. The calculation was carried out using comparative methods for calculating M.Kh. Karapetyan in the coordinates of "property-parameter" and "property-property." Least squares method was applied for processing the analytical description results with the choice of optimal dependencies on the maximum correlation coefficient and the minimum standard deviation. The analysis of the interrelation of the calculated numerical values with similar characteristics for NaAt и LiAt is presented. Comparison of the specific conductivity obtained numerical values of the astatide potassium melt showed good consistency with the values ӕ obtained from the straight line dependence ӕТпл+n = a∙ ӕТпл+5 (n = 10°…200°) and also with similar characteristics for lithium astatide and sodium astatide. The analytical calculation results allow to describe the temperature dependence of the potassium halogenides specific conductivity, including KAt. The calculation method can be used to describe the melts specific conductivity in the same type series of compounds of alkaline and alkaline-earth elements that make up electrolytes for chemical current sources.

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