Experimental Investigation On Wear Behavior of Rectangular Labyrinth Fin Against High Speed Rotor

2021 ◽  
Author(s):  
Xin Yan ◽  
Xinbo Dai
Keyword(s):  
Friction Coefficient ◽  
High Speed ◽  
Wear Behavior ◽  
Early Stage ◽  
Labyrinth Seal ◽  
Contact Forces ◽  
Transient Temperature ◽  
Sliding Velocity ◽  
Material Loss ◽  
Temperature Distributions

Abstract The wear behaviors of a rectangular labyrinth seal fin against high speed rotor were experimentally investigated on the incursion test rig. The material losses, worn geometries, frictional temperature distributions, and contact forces of labyrinth fin in rubbing events were measured at three incursion rates, three final incursion depths and two rotor sliding velocities. The morphologies of the worn labyrinth fin tips were magnified to reveal the wear mechanisms in rubbing events. The transient temperatures and contact forces were detailed to analyze the thermal-mechanical interactions between two contacting parts. The results show that the material loss percentage in the labyrinth fin is higher at the early stage of rubbing process, accounting for 18% mass loss of the worn region, than at final stage. The material loss is decreased with increasing the incursion rate. The incursion rate and final incursion depth have pronounced effects on the mushroom region extensions and curlings. The friction coefficient is fluctuated significantly in the high sliding velocity and low incursion rate conditions, and the averaged value of friction coefficient is about 0.1-0.125 among all experiments. The temperature at labyrinth fin tip is increased with increasing the final incursion depth, incursion rate and sliding velocity. However, the temperature at fin tip is not increased further as it reaches about 1200°C. The heat convection from hot fin to ambient plays an important role in worn geometries and transient temperature distributions at fin tip.

Experimental Study on Rubbing Wear Characteristics of Labyrinth Seal with Trapezoidal Fins

2021 ◽  
pp. 1-42
Author(s):  
Xin Yan ◽  
Xinbo Dai ◽  
Kun He
Keyword(s):  
Mass Loss ◽  
High Speed ◽  
Wear Behavior ◽  
Early Stage ◽  
Labyrinth Seal ◽  
Contact Forces ◽  
Sliding Velocity ◽  
Wear Performance ◽  
Wear Characteristics ◽  
Geometrical Effect

Abstract The wear characteristics of trapezoidal fin against high speed rotor were experimentally investigated at different final incursion depths, incursion rates, and sliding velocities. To characterize the geometrical effect, a small specimen (SS) and a large specimen (LS) were selected to analyze the mass loss, wear geometry, contact forces, and frictional temperature distributions under different conditions. The results show that the contact-separation is most likely to occur between the trapezoidal fin and rotor. In the rubbing process, the plastic deformation is dominating, and the abrasive and adhesive wears have pronounced effects on the wear behavior of rubbing interface. The wear performance of the SS is sensitive to the structure imbalance, which induces the combined mushrooming and bending damage in the trapezoidal fin. However, the symmetrical mushrooming damage is generated in the LS. For both SS and LS, the mass loss is decreased with increasing the incursion rate and sliding velocity, and the mass loss percentage is pronounced at the early stage of rubbing. The averaged friction coefficient is 0.1-0.16 for the LS, while 0.1-0.19 for the SS. The peak frictional temperature is 560-640 °C for the LS, while 360-400 °C for the SS. The contact-separation significantly reduces the effects of final incursion depth, incursion rate, and sliding velocity on the wear geometry, contact forces and temperature rise in the trapezoidal labyrinth fin.

Study on Friction Properties of Cu-Fe-Based Powder Metallurgy Materials under Dry and Wet Friction Conditions

2010 ◽  
Vol 150-151 ◽  
pp. 1806-1809 ◽  
Author(s):  
Rong Fu ◽  
Fei Gao ◽  
Bao Yun Song
Keyword(s):  
Powder Metallurgy ◽  
Friction Coefficient ◽  
High Speed ◽  
Wear Behavior ◽  
Water Film ◽  
Powder Metallurgy Process ◽  
Wet Friction ◽  
Friction Pressure ◽  
Pressure Changes ◽  
Metallurgy Process

Copper-iron-based friction materials were prepared by powder metallurgy process. The effects of friction velocity and friction pressure on friction and wear behavior of the material under dry and wet friction conditions were investigated with a constant-speed friction machine. The results show that, at low speed friction, the dry friction coefficient is higher than wet friction coefficient and the friction coefficient increases with increasing friction pressure. The reason is that the water film plays an important role in cleaning and lubricating. At high speed friction, there is not much difference between dry and wet friction coefficients and the friction coefficient is not sensitive to friction pressure changes. This is due to the metal matrix high-temperature softening, caused by high speed friction, which controls the friction properties.

Aerodynamic Heating Numerical Simulation of Terminal-Sensitive Projectile at Deceleration and Despinning Trajectory

2013 ◽  
Vol 376 ◽  
pp. 317-322
Author(s):  
Jun Zhang ◽  
Rong Zhong Liu ◽  
Rui Guo ◽  
Xiao Dong Ma
Keyword(s):  
Numerical Simulation ◽  
High Speed ◽  
Thermal Protection ◽  
Thermal Characteristics ◽  
Simulation Method ◽  
Aerodynamic Heating ◽  
Transient Temperature ◽  
Physical Parameters ◽  
Temperature Distributions ◽  
Infrared Signature

Aero-heating problem severely affects the performance of terminal-sensitive projectile (TSP) when projected out of the carrier capsule by the gunpowder gas at a high speed. In this paper, based on the typical ballistic data and airflow physical parameters at deceleration and despinning trajectory, the aerodynamic thermal characteristics of a TSP was simulated by Fluent, and the transient temperature distributions were obtained under the different flying conditions. Finally, we got stagnation temperatures by the numerical simulations which were similar to those by the engineering evaluation, and demonstrate the effectiveness of the simulation method. The results are valuable to the research of thermal protection and infrared signature of TSP.

scholarly journals Friction and Wear Behavior of Polyimide Composites Reinforced by Surface-Modified Poly-p-Phenylenebenzobisoxazole (PBO) Fibers in High Ambient Temperatures

Polymers ◽  
2019 ◽  
Vol 11 (11) ◽  
pp. 1805
Author(s):  
Yu ◽  
Zhang ◽  
Tang ◽  
Gao
Keyword(s):  
Wear Resistance ◽  
Friction Coefficient ◽  
Wear Rate ◽  
Friction And Wear ◽  
Wear Behavior ◽  
Specific Wear Rate ◽  
Interface Properties ◽  
Sliding Velocity ◽  
Friction And Wear Behavior ◽  
Ambient Temperatures

(1) In order to improve the properties of antifriction and wear resistance of polyimide (PI) composite under high temperature conditions, (2) 3-Aminopropyltriethoxysilane (APTES) and Lanthanum (La) salt modifications were employed to manufacture poly-p-phenylenebenzobisoxazole (PBO)/PI composites with different interface properties. The representative ambient temperatures of 130 and 260 °C were chosen to study the friction and wear behavior of composites with different interface properties. (3) Results revealed that while both modification methods can improve the chemical activity of the surface of PBO fibers, the La salt modification is more effective. The friction coefficient of all composites decreases with the increase of sliding velocity and load at two temperatures, and the specific wear rate is increases. Contrary to the situation in the 130 °C environment, the wear resistance of the unmodified composite in the 260 °C environment is greatly affected by the sliding velocity and load, while the modified composites are less affected. Under the same test parameters, the PBO–La/PI composite has the lowest specific wear rate and friction coefficient, and (4) La salt modification is a more effective approach to improve the properties of antifriction and wear resistance of PI composite than APTES modification in high ambient temperatures.

A Study on the Properties, Friction, Wear and Adhesion of HVOF Thermal Spray Coating of Micron Size Co-Alloy Powder

2009 ◽  
Vol 75 ◽  
pp. 19-24 ◽  
Author(s):  
Tong Yul Cho ◽  
Jae Hong Yoon ◽  
Ki Oh Song ◽  
Yun Kon Joo ◽  
Jae Young Cho ◽  
...  
Keyword(s):  
Friction Coefficient ◽  
Surface Temperature ◽  
Surface Properties ◽  
High Speed ◽  
Wear Behavior ◽  
Spray Coating ◽  
Thermal Spray Coating ◽  
Sliding Surface ◽  
Hvof Thermal Spray ◽  
Micron Size

High velocity oxygen fuel (HVOF) thermal spray coating of micron size (μ) T800 powder has been studied for the durability improvement of sliding machine components. The optimal coating process (OCP), surface properties, friction, wear behavior and adhesion of HVOF T800 coating have been investigated. The temperature dependence of friction coefficient and wear behavior have been studied at 25°C and at an elevated temperature 538°C (1,000°F) for the study of the temperature effects on FC and wear behaviors of the coating and for the application on high speed air bearing spindle which operates with no lubricants. The OCP was determined from the best surface properties of the 16 OCP searching coatings designed by the Taguchi experimental program of four spray parameters with three levels: a hydrogen flow rate (FR) of 38-42 FMR (1 FMR=12scfh=9.44×10-5 m/s), oxygen FR of 65-70 FMR and feed rate of 30 g/min, and a spray distance of 5 inch. Hardness, roughness and porosity observed from the 16 coatings were 560-640 Hv (5488-6272 MPa), 2.2-3.0 μm and 0.01-0.04% respectively. Friction coefficient (FC) decreased from 5.5-7.0 to 4.8-6.0 with increasing the sliding surface temperature from 25°C to 538°C because of the higher lubrication effect of Co oxide debris at the higher temperature. Wear trace of the coating and counter sliding SUS 304 surface decreased to more than a half with increasing the sliding surface temperature from 25°C to 538°C. Tensile bond strength (TBS) and tensile fracture location (TFL) of Ti64 / T800 were 8,770 psi (60.5 MPa) and near the middle of the coating respectively. Bond coat NiCr did not influence on the TBS of the coating. The adhesion between Ti64 substrate and T800 coating (Ti64/T800) was stronger than the cohesion strength 8,770 psi (60.5 MPa) of T800 coating. These showed that Ti64/T800 coating was recommendable for durability improvement coating on high speed spindle of Ti64.

Wear Prediction of Strip Seals Through Conductance

2004 ◽  
Author(s):  
Farshad Ghasripoor ◽  
Norman A. Turnquist ◽  
Mark Kowalczyk ◽  
Bernard Couture
Keyword(s):  
Thermal Conductivity ◽  
High Speed ◽  
Wear Behavior ◽  
Close Correlation ◽  
Labyrinth Seal ◽  
The Body ◽  
Minor Effect ◽  
Labyrinth Seals ◽  
Steam Leakage ◽  
A Minor

Labyrinth seal assemblies are often used to reduce gas and/or steam leakage in turbines. Caulked-in continuous strip seals are one of the common forms of seals employed on both the rotating and stationary components of turbines. Labyrinth seals perform best when minimum clearances are achieved during the steady state operation of the turbine. However, the design of the turbine and its operation during transient periods of start-up, shut-down and hot re-start often result in interference between the seal components. In the case of the strip seals, this leads primarily to wear of the strip, which in effect adds to leakage. The aim of this paper is to show that strip tip heating and melting during the rub is the main mechanism of wear in the strip. Hence thermal conductivity through the strip and into the body mass in which it is caulked is the primary controlling factor in seal wear. This paper will discuss the use of thermal conductivity and geometry of the strip in predicting wear during high speed rubs against a proprietary material. A close correlation between calculated and experimental strip seal wear data with a number of seal alloys will be demonstrated. Test data will indicate that material properties such as tensile strength and hardness have a minor effect on the wear behavior of continuous seal elements during high-speed rubs.

Experimental Study on the Friction Contact Between a Labyrinth Seal Fin and a Honeycomb Stator

2015 ◽  
Vol 138 (6) ◽  
Author(s):  
Tim Pychynski ◽  
Corina Höfler ◽  
Hans-Jörg Bauer
Keyword(s):  
Experimental Study ◽  
Friction Velocity ◽  
Wear Behavior ◽  
Labyrinth Seal ◽  
Contact Forces ◽  
Metal Foil ◽  
Labyrinth Seals ◽  
Friction Temperature ◽  
Rubbing Behavior ◽  
Set Up

This paper presents results from an extensive experimental study on the rubbing behavior of labyrinth seal fins (SFs) and a honeycomb liner. The objective of the present work is to improve the understanding of the rub behavior of labyrinth seals by quantifying the effects and interactions of sliding speed, incursion rate, seal geometry, and SF rub position on the honeycomb liner. In order to reduce the complexity of the friction system studied, this work focuses on the contact between a single SF and a single metal foil. The metal foil is positioned in parallel to the SF to represent contact between the SF and the honeycomb double foil section. A special test rig was set up enabling the radial incursion of a metal foil into a rotating labyrinth SF at a defined incursion rate of up to 0.65 mm/s and friction velocities up to 165 m/s. Contact forces, friction temperatures, and wear were measured during or after the rub event. In total, 88 rub tests including several repetitions of each rub scenario have been conducted to obtain a solid data base. The results show that rub forces are mainly a function of the rub parameters incursion rate and friction velocity. Overall, the results demonstrate a strong interaction between contact forces, friction temperature, and wear behavior of the rub system. The presented tests confirm basic qualitative observations regarding blade rubbing provided in literature.

scholarly journals An Experimental Study of Composite Plain Bearings: The Influence of Clearance on Friction Coefficient and Temperature

2019 ◽  
pp. 547-556 ◽  
Author(s):  
Daniel Miler ◽  
Stanko Škec ◽  
Branko Katana ◽  
Dragan Žeželj
Keyword(s):  
Surface Roughness ◽  
Friction Coefficient ◽  
Working Conditions ◽  
Friction And Wear ◽  
Solid Lubricant ◽  
Low Cost ◽  
Sliding Velocity ◽  
Wear Properties ◽  
Material Loss ◽  
Experimental Rig

Plain bearings are often used due to their compact dimensions and low cost. Their frictional and wear properties are affected by several parameters: load, sliding velocity, temperature, and surface roughness, among others. In this article, the authors have experimentally investigated the influence of clearance size on the friction and wear in composite plain bearings. An experimental rig was designed to enable the testing of plain bearings in working conditions similar to those encountered throughout their exploitation. Two load levels, two lubrication types, and four clearance levels were varied, resulting in 48 experiments, as each was replicated twice. The friction coefficient and bearing temperature were measured during the experiment, while the material loss and change in surface roughness were determined post-experiment. The results have shown that clearance affects the friction in both the dry running specimens and specimens lubricated using a solid lubricant (polytetrafluoroethylene).

Friction and Wear Behavior of TiN/TiAlN Coated Ti(C,N)-Based Cermets

2008 ◽  
Vol 368-372 ◽  
pp. 1307-1309 ◽  
Author(s):  
Li Yun Zheng ◽  
Li Xin Zhao ◽  
Jing Jun Zhang
Keyword(s):  
Friction Coefficient ◽  
Sliding Wear ◽  
Friction And Wear ◽  
Adhesive Wear ◽  
Wear Behavior ◽  
Wear Test ◽  
Sliding Velocity ◽  
Friction And Wear Behavior ◽  
Ion Plating ◽  
The Mean

Ti(C,N)-based cermets were coated with a TiN/TiAlN coating using ion plating technology. The sliding wear test was performed for the coated cermets and the microstructure, composition and surface roughness of the coated cermets under different velocities and loads were characterized. The results showed that the friction coefficients of the coated cermets were lower than that of the neat cermets. Under the same load, the adhesion phenomenon of the counterpart materials on the specimens was improved and the mean friction coefficient increased with increasing sliding speed. Under the same sliding velocity, the average friction coefficient of the coated cermets was lower under higher load. The wear mechanisms were mainly adhesive wear and abrasive wear.

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