Analysis of three-dimensional non-axisymmetric elastic effects of the lip on the thermoelastohydrodynamic radial lip seal behaviour

2007 ◽  
Vol 221 (8) ◽  
pp. 859-868 ◽  
Author(s):  
A Maoui ◽  
M Hajjam ◽  
D Bonneau
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Numerical Models ◽  
Three Dimensional ◽  
Operating Characteristics ◽  
Lip Seal ◽  
Lip Seals ◽  
Deformation Distribution

Numerical models, proposed to analyse the elastohydrodynamic and thermoelastohydrodynamic (TEHD) behaviour of radial lip seals, have been considered in terms of an axisymmetrical approach to elastic seal deformation. However, the results obtained using a non-axisymmetrical elastic approach to investigating the tip of the lip differed from the axisymmetrical approach results in relation to the deformation distribution of the lip surface. The main objective of the present work is to show through numerical analysis the three-dimensional nonaxisymmetric effect of the lip deformations on the TEHD behaviour of radial lip seals. Hence, a comparison between both elastic approaches is presented in order to analyse the influence of the lip's non-axisymmetric behaviour on all of the operating characteristics of the lip seal. In addition, different forms of the lip surface roughness are investigated.

Numerical Analysis of the Flow Field Within Lip Seals Containing Microundulations

1992 ◽  
Vol 114 (3) ◽  
pp. 485-491 ◽  
Author(s):  
R. F. Salant
Keyword(s):  
Numerical Analysis ◽  
Flow Field ◽  
Shear Deformation ◽  
Leakage Rate ◽  
Shaft Speed ◽  
Rotating Shaft ◽  
Lip Seal ◽  
Lubricating Film ◽  
Lip Seals

The flow field within the lubricating film of a rotating shaft lip seal containing microundulations is analyzed numerically. The results demonstrate that the action of the microundulations can prevent leakage through the seal. The effects on leakage rate of shaft speed, undulation amplitude and wavelength, shear deformation of the undulations, flattening of the undulations, and axial lip profile are presented.

Numerical Analysis of Fluid Flow Through an Electrical Submersible Pump for Handling Viscous Liquid

2016 ◽  
Author(s):  
Md. Hamid Siddique ◽  
Sanoop Manayilthodiyil ◽  
Afzal Husain ◽  
Abdus Samad ◽  
Frank Kenyery
Keyword(s):  
Surface Roughness ◽  
Numerical Analysis ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Numerical Approach ◽  
Fluid Viscosity ◽  
Submersible Pump ◽  
Sharp Drop ◽  
Flow Passage ◽  
Electrical Submersible Pump

Generally, artificial lifts to pump crude oil having a high viscosity from wellbores using an electrical submersible pump (ESP) are not efficient. The present study consists of a numerical approach to understand the effect of fluid viscosity and surface roughness of the flow passage on the performance of an ESP. A three-dimensional numerical analysis was carried out using Reynolds-averaged Navier-Stokes equations at different off-design conditions. The standard k-ε turbulence model was used for the steady incompressible flow. Water and crude oils having different viscosities were used as working fluids and numerical analyses were made by varying surface roughness of the flow passage. Although there was a sharp drop in the efficiency with the increase in surface roughness, but the combined effect of viscosity and surface roughness showed an increase in efficiency up to a certain fluid viscosity.

Numerical Analysis of a Laboratory Centrifugal Pump for the Training of Graduate Engineers

2006 ◽  
Author(s):  
G. Cenci ◽  
M. Pinelli
Keyword(s):  
Numerical Simulation ◽  
Numerical Analysis ◽  
Centrifugal Pump ◽  
Numerical Models ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Industrial Applications ◽  
Basic Knowledge ◽  
Grid Turbulence ◽  
Turbomachinery Design

The up-to-date design of turbomachinery involves the use of three dimensional computational fluid dynamic analyses to match the challenge of the ever increasing speed of product development. Recently, the application of these analyses to turbomachinery, which in past years was confined to specialist fields, has become widespread in many industrial applications. Hence, besides the teaching of traditional methods for turbomachinery design, an important part of modern engineering education is to produce graduates with advanced skills in Computational Fluid Dynamics (CFD) techniques applied to turbomachinery design. Moreover, at this time, these skills should either match the needs of research laboratories or be compatible with industrial needs, since three dimensional numerical calculation is also coming to be seen as a feasible tool in ordinary applications. For these reasons, CFD courses for the training of graduate students have been developed. In this paper, the methodology followed and the work carried out by the students of the course in Fluid Dynamic Design of Turbomachinery held at the University of Ferrara is presented. In particular, three levels of investigation are taken into consideration and presented: (i) focus on the fundamentals to achieve a basic knowledge of a design process based on numerical simulation; (ii) extension to higher level of in-depth analyses of the specific models which could be used in every phase of a numerical simulation; (iii) insight into the specificity of the main thermodynamic and fluid dynamic characteristics of turbomachinery. To achieve this, the numerical analysis of a simple but exhaustive geometry of a centrifugal pump has been carried out and the results obtained are analyzed. In particular, special emphasis is devoted to: (i) the comparison among the numerical models which can be chosen throughout the simulations of turbomachinery (type of grid, turbulence models, rotor/stator interface models) and (ii) the analysis of some of the most important fluid dynamic phenomena, such as, in this case, velocity profiles and jet-and-wake structure.

Three dimensional numerical analysis of heat transfer during spray quenching of 22MnB5 steel with a single nozzle

2020 ◽  
Author(s):  
Emre Bulut ◽  
Gökhan Sevilgen ◽  
Ferdi Eşiyok ◽  
Ferruh Öztürk ◽  
Tuğçe Turan Abi
Keyword(s):  
Heat Transfer ◽  
Numerical Analysis ◽  
Three Dimensional ◽  
22Mnb5 Steel

Enhancement of Heat Transfer Performance in Nuclear Fuel Rod Using Nanofluids and Surface Roughness Technique

2015 ◽  
Author(s):  
Kang Liu ◽  
Titan C. Paul ◽  
Leo A. Carrilho ◽  
Jamil A. Khan
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Heat Transfer Coefficient ◽  
Transfer Coefficient ◽  
Nuclear Fuel ◽  
Three Dimensional ◽  
Pressurized Water ◽  
Bulk Fluid ◽  
Fuel Rod ◽  
Dimensional Surface

The experimental investigations were carried out of a pressurized water nuclear reactor (PWR) with enhanced surface using different concentration (0.5 and 2.0 vol%) of ZnO/DI-water based nanofluids as a coolant. The experimental setup consisted of a flow loop with a nuclear fuel rod section that was heated by electrical current. The fuel rod surfaces were termed as two-dimensional surface roughness (square transverse ribbed surface) and three-dimensional surface roughness (diamond shaped blocks). The variation in temperature of nuclear fuel rod was measured along the length of a specified section. Heat transfer coefficient was calculated by measuring heat flux and temperature differences between surface and bulk fluid. The experimental results of nanofluids were compared with the coolant as a DI-water data. The maximum heat transfer coefficient enhancement was achieved 33% at Re = 1.15 × 105 for fuel rod with three-dimensional surface roughness using 2.0 vol% nanofluids compared to DI-water.

scholarly journals Effect of Optical and Morphological Control of Single-Structured LEC Device

Micromachines ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 843
Author(s):  
Woo Jin Jeong ◽  
Jong Ik Lee ◽  
Hee Jung Kwak ◽  
Jae Min Jeon ◽  
Dong Yeol Shin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Surface Roughness ◽  
Surface Properties ◽  
High Efficiency ◽  
High Surface ◽  
Reduction Rate ◽  
Operating Characteristics ◽  
Emission Layer ◽  
Light Emitting ◽  
Stable Operating

We investigated the performance of single-structured light-emitting electrochemical cell (LEC) devices with Ru(bpy)3(PF6)2 polymer composite as an emission layer by controlling thickness and heat treatment. When the thickness was smaller than 120–150 nm, the device performance decreased because of the low optical properties and non-dense surface properties. On the other hand, when the thickness was over than 150 nm, the device had too high surface roughness, resulting in high-efficiency roll-off and poor device stability. With 150 nm thickness, the absorbance increased, and the surface roughness was low and dense, resulting in increased device characteristics and better stability. The heat treatment effect further improved the surface properties, thus improving the device characteristics. In particular, the external quantum efficiency (EQE) reduction rate was shallow at 100 °C, which indicates that the LEC device has stable operating characteristics. The LEC device exhibited a maximum luminance of 3532 cd/m2 and an EQE of 1.14% under 150 nm thickness and 100 °C heat treatment.

Optimization of the Navy’s three-dimensional mine impact burial prediction simulation model, Impact35, using high-order numerical methods

2021 ◽  
pp. 154851292110286
Author(s):  
Athanasios Donas ◽  
Ioannis Famelis ◽  
Peter C Chu ◽  
George Galanis
Keyword(s):  
Numerical Analysis ◽  
Numerical Methods ◽  
Prediction Model ◽  
Simulation Model ◽  
Three Dimensional ◽  
Simulation System ◽  
High Order ◽  
Alternative Methodology ◽  
Runge Kutta ◽  
Fifth Order

The aim of this paper is to present an application of high-order numerical analysis methods to a simulation system that models the movement of a cylindrical-shaped object (mine, projectile, etc.) in a marine environment and in general in fluids with important applications in Naval operations. More specifically, an alternative methodology is proposed for the dynamics of the Navy’s three-dimensional mine impact burial prediction model, Impact35/vortex, based on the Dormand–Prince Runge–Kutta fifth-order and the singly diagonally implicit Runge–Kutta fifth-order methods. The main aim is to improve the time efficiency of the system, while keeping the deviation levels of the final results, derived from the standard and the proposed methodology, low.

scholarly journals Air Ventilation Performance of School Classrooms with Respect to the Installation Positions of Return Duct

2021 ◽  
Vol 13 (11) ◽  
pp. 6188
Author(s):  
Sungwan Son ◽  
Choon-Man Jang
Keyword(s):  
Air Quality ◽  
Numerical Analysis ◽  
Indoor Air Quality ◽  
Indoor Air ◽  
Three Dimensional ◽  
Cross Infection ◽  
School Students ◽  
Height Range ◽  
Air Ventilation ◽  
Ventilation Performance

For students, who spend most of their time in school classrooms, it is important to maintain indoor air quality (IAQ) to ensure a comfortable and healthy life. Recently, the ventilation performance for indoor air quality in elementary schools has emerged as an important social issue due to the increase in the number of days of continuous high concentrations of particulate matter. Three-dimensional numerical analysis has been introduced to evaluate the indoor airflow according to the installation location of return diffusers. Considering the possibility of the cross-infection of infectious diseases between students due to the direction of airflow in the classroom, the airflow angles of the average respiratory height range of elementary school students, between 1.0 and 1.5 m, are analyzed. Throughout the numerical analysis inside the classroom, it is found that the floor return system reduces the indoor horizontal airflow that causes cross-infection among students by 20% compared to the upper return systems. Air ventilation performance is also analyzed in detail using the results of numerical simulation, including streamlines, temperature and the age of air.

scholarly journals Experimental and Numerical Investigation of 3D Dam-Break Wave Propagation in an Enclosed Domain with Dry and Wet Bottom

2021 ◽  
Vol 11 (12) ◽  
pp. 5638
Author(s):  
Selahattin Kocaman ◽  
Stefania Evangelista ◽  
Hasan Guzel ◽  
Kaan Dal ◽  
Ada Yilmaz ◽  
...  
Keyword(s):  
Wave Propagation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Dam Break ◽  
Dam Failure ◽  
Navier Stokes ◽  
Negative Wave ◽  
Through Flow ◽  
Instantaneous Removal ◽  
Surface Patterns

Dam-break flood waves represent a severe threat to people and properties located in downstream regions. Although dam failure has been among the main subjects investigated in academia, little effort has been made toward investigating wave propagation under the influence of tailwater depth. This work presents three-dimensional (3D) numerical simulations of laboratory experiments of dam-breaks with tailwater performed at the Laboratory of Hydraulics of Iskenderun Technical University, Turkey. The dam-break wave was generated by the instantaneous removal of a sluice gate positioned at the center of a transversal wall forming the reservoir. Specifically, in order to understand the influence of tailwater level on wave propagation, three tests were conducted under the conditions of dry and wet downstream bottom with two different tailwater depths, respectively. The present research analyzes the propagation of the positive and negative wave originated by the dam-break, as well as the wave reflection against the channel’s downstream closed boundary. Digital image processing was used to track water surface patterns, and ultrasonic sensors were positioned at five different locations along the channel in order to obtain water stage hydrographs. Laboratory measurements were compared against the numerical results obtained through FLOW-3D commercial software, solving the 3D Reynolds-Averaged Navier–Stokes (RANS) with the k-ε turbulence model for closure, and Shallow Water Equations (SWEs). The comparison achieved a reasonable agreement with both numerical models, although the RANS showed in general, as expected, a better performance.

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