Numerical Simulation of Film Thickness Formation in a PFI Engine Under Motoring Conditions

2019 ◽  
Vol 9 (3) ◽  
pp. 11-15
Author(s):  
Ramesh P ◽  
James Gunasekaran E
Keyword(s):  
Numerical Simulation ◽  
Film Thickness

NUMERICAL INVESTIGATION OF FILM DISTRIBUTION IN HORIZONTAL-TUBE FALLING FILM EVAPORATOR

2011 ◽  
Vol 19 (03) ◽  
pp. 177-183 ◽  
Author(s):  
JIN-BO CHEN ◽  
QING-GANG QIU
Keyword(s):  
Numerical Simulation ◽  
Fluid Flow ◽  
Film Thickness ◽  
Liquid Film ◽  
Numerical Investigation ◽  
Horizontal Tube ◽  
Flow Density ◽  
Falling Film ◽  
Film Distribution ◽  
Simulation Results

The technique of horizontal-tube falling film has been used in the cooling and heating industries such as refrigeration systems, heating systems and ocean thermal energy conversion systems. The comprehensive performance of evaporator is directly affected by the film distribution characteristics outside tubes. In this paper, numerical investigation was performed to predict the film characteristics outside the tubes in horizontal-tube falling film evaporator. The effects of liquid flow rate, tube diameter and the circular degree of tube on the film thickness were presented. The numerical simulation results were compared with that of the empirical equations for calculating the falling film thickness, and agreements between them were reasonable. Numerical simulation results show that, at the fixed fluid flow density, the liquid film is thicker on the upper and lower tube and the thinnest liquid film appears at angle of about 120°. The results also indicate that, when the fluid flow density decreases to a certain value, the local dryout spot on the surface of the tube would occur. In addition, the film thickness decreases with the increases of the tube diameter at the fixed fluid flow density.

Numerical Simulation on Variable Load EHL Problems with Single Asperities

2015 ◽  
Vol 642 ◽  
pp. 89-93
Author(s):  
Jian Jun Zhang ◽  
Cheng Long Liu ◽  
Feng Guo
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Pressure Change ◽  
Numerical Results ◽  
Variable Load ◽  
Line Contact ◽  
Load Line ◽  
Steady Load

A model of the problem of variable load line contact EHL with single asperities is established. The influences of the single asperities and variable load on the pressure and film thickness are investigated. Numerical results reveal that the existence of single asperities can lead to pressure change drastically and film thickness become thin in the vicinity of asperities. The effects of the variable load on the pressure and film thickness are discussed. The comparison of the variable load and steady load is given.

Numerical Simulation on the Lubrication Performance of Surface Textured Piston Rings

2011 ◽  
Vol 199-200 ◽  
pp. 734-738 ◽  
Author(s):  
Qiu Ying Chang ◽  
Xian Liang Zheng ◽  
Qing Liu
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Friction Force ◽  
Friction And Wear ◽  
Piston Ring ◽  
Hydrodynamic Lubrication ◽  
Cylinder Liner ◽  
Area Density ◽  
Oil Film ◽  
Lubrication Performance

Surface texturing has been successfully employed in some tribological applications in order to diminish friction and wear. This technology may be used in a piston ring to decrease the friction and wear of the contact between a piston ring and cylinder liner. A numerical simulation of lubrication between a surface textured piston ring and cylinder liner based on the hydrodynamic lubrication theory was conducted. The influence of surface texture parameters on piston ring lubrication performance was obtained by solving the mathematical equations with a multi-grid method. The results show that under the micro-dimple area density of 5%-40% the minimum oil film thickness increases and the dimensionless friction force decreases with the increasing of it. Under the dimple area density of 40%-60%, the minimum oil film thickness and the dimensionless friction force change slightly. Under various dimple area densities the optimum dimple depth at the given working condition in this paper is about 5µm.

scholarly journals Research on Distribution Properties of Coating Film Thickness from Air Spraying Gun-Based on Numerical Simulation

Coatings ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 721 ◽  
Author(s):  
Xiaopeng Xie ◽  
Yinan Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Film Thickness ◽  
Coating Thickness ◽  
Thickness Distribution ◽  
Air Pressure ◽  
Reasonable Assumption ◽  
Coating Film ◽  
Discrete Phase Model ◽  
Spraying Process

This work aims to study the influence of the spraying parameters on the spray flow field and coating thickness distribution during the air spraying process. The shaping air pressure and the target geometry have an important influence on the distribution of coating film thickness. This paper begins with a 3-D physical model of an air spray gun, in which unstructured grids were generated for control domain. A grid independency study was also carried out to determine the optimal number of cells for the simulations. Then the Euler–Lagrange method was used to describe the two-phase spray flow by establishing a paint deposition model. The numerical simulation based on the discrete phase model (DPM) and TAB model has been carried out. A reasonable assumption was proposed based on the analysis of the spraying process, so that the droplets were injected into the airflow at the position of the paint hole. The influence of the shaping air pressure on the air flow field and the coating thickness distribution was analyzed by changing the shaping air pressure. From the numerical simulation results, it can be concluded that the smaller the shaping air pressure, the more concentrated the coating. With increasing the shaping air pressure, the length of the coating film along z-axis gradually increases, the width along x-axis gradually decreases, and the spray area gradually increases. The paper ends with a numerical simulation and experimental study on planar vertical spraying, planar tilted spraying, and cylinder spraying. Comparisons and experiment results verify the validity and practicability of the model built in this paper.

The Thermal Elastohydrodynamic Lubrication Analysis of Seawater-Lubricated Thordon Bearing

2011 ◽  
Vol 396-398 ◽  
pp. 2507-2510 ◽  
Author(s):  
Li Jing Zhang ◽  
You Qiang Wang
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Thermal Effect ◽  
Thermal Condition ◽  
Reynolds Equation ◽  
Elastohydrodynamic Lubrication ◽  
Shaft Diameter ◽  
Pressure Peak

Based on Reynolds equation, the numerical simulation of thermal elstohydronamic lubrication for seawater-lubricated thordon bearing was carried out, the effects of the load, the speed and the shaft diameter on the pressure and the film thickness were discussed. The results show that thermal effect has little effect on the pressure, but the film thickness under the thermal condition is smaller than isothermal. The pressure peak is increased and the film thickness is decreased greatly with the increase of load. The pressure peak is decreased and the film thickness is increased greatly with the increase of speed.

Flying Characteristics of Head Sliders on Patterned Disk Surfaces

2005 ◽  
Author(s):  
Takefumi Hayashi ◽  
Hideyo Yoshida ◽  
Yasunaga Mitsuya
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Dynamic Characteristics ◽  
Averaging Method ◽  
Disk Surface ◽  
Simulation System ◽  
Molecular Gas ◽  
Static And Dynamic Characteristics ◽  
Head Slider ◽  
Gas Lubrication

To quantitatively predict the static, and dynamic characteristics of a head slider while flying over a patterned disk, the mixedly averaging method has been successfully applied to the molecular gas lubrication problem incurred by groove-shaped textures formed over the lubricating surface. First, formulation of ADI method by using mixedly averaged film thickness is derived and implemented into an interactive numerical simulation system. Then, spacing variations of typical sliders on a patterned disk surface are demonstrated.

Numerical Simulation of Oil Film State and Mechanical Performance of Heavy Hydrostatic Thrust Bearings

2013 ◽  
Vol 318 ◽  
pp. 148-152
Author(s):  
Yao Yao Hong ◽  
Li Jun Du ◽  
She Miao Qi
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Film Thickness ◽  
Pressure Distribution ◽  
Reynolds Equation ◽  
Mechanical Performance ◽  
The Finite Element Method ◽  
Oil Film ◽  
Thrust Bearings ◽  
Temperature And Pressure

The finite element method (FEM) is applied in the numerical simulation of heavy hydrostatic thrust bearings to study the influence of pressure and temperature on bearing deformation. The pressure distribution and the temperature distribution are obtained by solving the Reynolds equation and the energy equation. The bearing deformations caused by temperature and pressure are computed by imposing the two obtained distributions on the bearing. Because the pressure distribution and the temperature distribution are influenced by the oil film thickness and the oil film thickness is influenced by the bearing deformation, the numerical simulation is a process of iteration. The numerical results demonstrate that, in heavy hydrostatic thrust bearings, the thermal deformation and the mechanical deformation are both significant and can not be neglected. The influence of operation parameters on the anti-capsizing capability of heavy hydrostatic thrust bearings is also discussed. The obtained results reveal that, the anti-capsizing moment of the bearing increases with the decrease of the central thickness of the oil film.

Numerical Simulation of a Transverse Ridge in a Circular EHL Contact Under Rolling/Sliding

1994 ◽  
Vol 116 (4) ◽  
pp. 751-761 ◽  
Author(s):  
C. H. Venner ◽  
A. A. Lubrecht
Keyword(s):  
Numerical Simulation ◽  
Film Thickness ◽  
Thermal Behavior ◽  
Pressure Distribution ◽  
Central Axis ◽  
Transverse Ridge ◽  
Thickness Profile ◽  
Smooth Contact ◽  
Ehl Contact

This paper investigates the influence of a transverse ridge on the film thickness in a circular EHL contact under rolling/sliding conditions. It is a numerical simulation of the optical EHL work of Kaneta et al. (1992). One of the purposes of this investigation is to check the validity of the algorithm and the Newtonian, isothermal lubricant assumption for film thickness predictions under these conditions (ph = 0.54 GPa). It will be shown that, both quantitatively, the film thickness on the central axis Y = 0, and qualitatively, the film thickness profile through “pseudo interference graphs”, the agreement between experiment and Newtonian isothermal theory is good. This supports the argument that the rheological and the thermal behavior of the fluid only slightly influence the film thickness and pressure distribution of the lightly loaded non-smooth contact case.

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