scholarly journals Some Composite Bearing and Seal Materials for Gas Turbine Applications—A Review

1990 ◽  
Vol 112 (4) ◽  
pp. 486-491 ◽  
Author(s):  
H. E. Sliney
Keyword(s):  
Tribological Properties ◽  
High Speed ◽  
Composite Coatings ◽  
Cylinder Liner ◽  
Engine Operation ◽  
Start Up ◽  
Wide Range ◽  
Maximum Temperatures ◽  
Plasma Sprayed ◽  
Composite Bearing

A review is given of the selection and tribological testing of materials for high-temperature bearings and seals. The goal is to achieve good tribological properties over a wide range of temperatures, because bearings and seals must be functional from low-temperature start-up conditions on up to the maximum temperatures encountered during engine operation. Plasma-sprayed composite coatings with favorable tribological properties from 25 to 900°C are discussed. The performance of these coatings in simple tribological bench tests is described. Examples are also given of their performance in high-speed sliding contact seals, as Stirling cylinder liner materials, and as backup lubricants for compliant foil gas bearings.

scholarly journals Some Composite Bearing and Seal Materials for Gas Turbine Applications: A Review

1989 ◽  
Author(s):  
Harold E. Sliney
Keyword(s):  
Tribological Properties ◽  
High Speed ◽  
Composite Coatings ◽  
Cylinder Liner ◽  
Engine Operation ◽  
Start Up ◽  
Wide Range ◽  
Maximum Temperatures ◽  
Plasma Sprayed ◽  
Composite Bearing

A review is given of the selection and tribological testing of materials for high-temperature bearings and seals. The goal is to achieve good tribological properties over a wide range of temperatures because bearings and seals must be functional from low temperature start-up conditions on up to the maximum temperatures encountered during engine operation. Plasma sprayed composite coatings with favorable tribological properties from 25 to 900 °C are discussed. The performance of these coatings in simple tribological bench tests is described. Examples are also given of their performance in high-speed sliding contact seals, as Stirling cylinder liner materials, and as back up lubricants for compliant foil gas bearings.

Tribological properties of plasma sprayed Al/Al2O3 composite coatings

Wear ◽  
2007 ◽  
Vol 263 (7-12) ◽  
pp. 1430-1437 ◽  
Author(s):  
Zhijian Yin ◽  
Shunyan Tao ◽  
Xiaming Zhou ◽  
Chuanxian Ding
Keyword(s):  
Tribological Properties ◽  
Composite Coatings ◽  
Al2o3 Composite ◽  
Plasma Sprayed

scholarly journals Firing order selection for a V20 commercial diesel engine with FEV Virtual Engine

2017 ◽  
Vol 169 (2) ◽  
pp. 64-70
Author(s):  
Konrad BUCZEK ◽  
Sven LAUER
Keyword(s):  
Diesel Engine ◽  
Torsional Vibration ◽  
High Speed ◽  
Selection Process ◽  
Simulation Software ◽  
Dynamics Simulation ◽  
Order Selection ◽  
Engine Operation ◽  
Wide Range ◽  
Firing Order

The continuously increasing mechanical and thermal loads of modern engines require optimization of the designs with incorporation of a wide range of different aspects. Application of advanced computer simulations in the development process for most engine components is well established, leading to the creation of well optimized products. However, the optimization of such design variables ike the firing order, which influences engine operation in several disciplines, is still challenging. Considering the ever increasing peak firing pressure requirements, the layout of the firing order in multi-cylinder commercial engines is an efficient way to reduce crank train / overall engine vibration and main bearing loads, whilst controlling engine balancing and preserving adequate gas exchange dynamics. The proposed general firing order selection process for four-stroke engines and, in particular, its first part being the optimization of the firing order based on crank train torsional vibration, is the main topic of this paper. The exemplary study for a V20 high speed commercial Diesel engine regarding the influence of the firing sequence on crank train torsional vibration has been conducted with the multibody dynamics simulation software “FEV Virtual Engine”. It addresses various engine crankshaft layouts and engine applications.

Modeling Non-Newtonian Piston Skirts EHL in the Initial Engine Start Up

2010 ◽  
Author(s):  
Syed Adnan Qasim ◽  
Usman F. Chaudhri ◽  
M. Afzaal Malik ◽  
Riaz A. Mufti
Keyword(s):  
High Speed ◽  
Relaxation Times ◽  
Radial Clearance ◽  
Solution Technique ◽  
Engine Operation ◽  
Low Speed ◽  
Start Up ◽  
Piston Skirts ◽  
Engine Start ◽  
Speed Engine

In the normal high speed engine operation at small piston-to-bore radial clearance, elastohydrodynamic lubrication (EHL) of skirts and non-Newtonian lubricant behavior prevent adhesive wear, but in the initial engine start up, the large clearance, low speed and absence of EHL, cause start up wear. This study models 2-D upper convected Maxwell viscoelastic EHL of piston skirts at small radial clearance in a few initial low speed engine start up cycles by solving the Reynolds equation and using the inverse solution technique. The numerical analysis incorporate characteristic lubricant relaxation times and a perturbation method to predict and compare hydrodynamic and EHL pressures and film profiles. The effects of viscoelasticity on the lubricant characteristics, transverse eccentricities of piston, film thickness, and pressure fields in the hydrodynamic and EHL regimes are investigated. This study suggests that EHL film is formed at very small piston-to-bore radial clearance at low start up speed under assumed conditions to prevent start up wear as viscoelasticity produces a beneficial effect on piston skirts lubrication in the initial engine start up.

Microstructure and tribological properties of plasma sprayed TiCN-Mo based composite coatings

2019 ◽  
Vol 464 ◽  
pp. 88-98 ◽  
Author(s):  
Fanyong Zhang ◽  
Chao Li ◽  
Shu Yan ◽  
Jining He ◽  
Baoxi Liu ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Composite Coatings ◽  
Plasma Sprayed

Effect of Nd2O3 Additive on Microstructure and Tribological Properties of Plasma-Sprayed NiCr-Cr2O3 Composite Coatings

2013 ◽  
Vol 23 (3) ◽  
pp. 363-372 ◽  
Author(s):  
Jie Chen ◽  
Yulong An ◽  
Xiaoqin Zhao ◽  
Fengyuan Yan ◽  
Huidi Zhou ◽  
...  
Keyword(s):  
Tribological Properties ◽  
Composite Coatings ◽  
Plasma Sprayed

Effects of High Initial Engine Start Up Speeds in Isothermal Fluid Flow and Piston Skirts EHL

2011 ◽  
Author(s):  
Syed Adnan Qasim ◽  
M. Afzaal Malik
Keyword(s):  
Film Thickness ◽  
High Speed ◽  
Adhesive Wear ◽  
Cooling System ◽  
Cylinder Liner ◽  
Operating Conditions ◽  
Solution Technique ◽  
Start Up ◽  
Piston Skirts ◽  
Engine Start

In the medium and high speed normal engine operating conditions a fully established elastohydrodynamic lubricating (EHL) film between the piston skirts and cylinder liner surfaces reduces friction and prevents adhesive wear. In the initial engine start up the absence of EHL film causes wear of piston skirts, especially at high speeds. In a few initial cold engine start up cycles, a highly efficient cooling system may not let the temperature to rise significantly and affect the viscosity and other characteristics of a lubricant. In view of the vulnerability of piston skirts to adhesive wear at high initial engine start up speeds, the hydrodynamic and EHL of piston skirts is modeled numerically. A 2-D Reynolds equation is solved by coupling the secondary piston motion and using a finite difference scheme. Transient hydrodynamic film thickness profiles are generated at a relatively high engine start up speed. In the EHL regime, the profiles of rising hydrodynamic pressures and film thicknesses are predicted by using the inverse solution technique in fully flooded conditions. The study is extended to a range of high engine start up speeds while using a fairly viscous engine lubricant. Numerical simulations show significant changes in the piston eccentricities and film thickness profiles in the hydrodynamic and EHL regimes at different start up speeds. Such variations alter the hydrodynamic and EHL pressures and visibly affect the load carrying capacity of the lubricant. This study suggests to optimize the high engine start up speed for the given viscosity grade engine lubricant when considering the vulnerability of skirts and liner surfaces to adhesive wear in the initial engine start up.

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