scholarly journals An investigation into the role of specimen geometry when undertaking tribological testing on seal fin components

2021 ◽  
pp. 095440622110250
Author(s):  
Boxiu Zhang ◽  
Matthew Marshall ◽  
Roger Lewis
Keyword(s):  
Wear Mechanism ◽  
High Speed ◽  
Heat Removal ◽  
Labyrinth Seal ◽  
Specimen Geometry ◽  
Speed Test ◽  
Sealing Performance ◽  
Post Test ◽  
Surface Examination

Labyrinth seal systems are used in aeroengines to seal the clearance, the understanding of the wear mechanism of labyrinth seal system is necessary to achieve better sealing performance. In this work a series of tests are conducted on a high-speed test rig capable of fin tip speeds of 100 m/s. With force and temperature measurements recorded in each case, the influence of specimen geometry is investigated. Surface examination and debris analysis is also performed using microscopy post-test. The wear mechanism was found to be influenced by fin geometry. A discrete fin was observed to trigger a more efficient material removal mechanism at both incursion conditions. Where the fin segment and ring-shaped fin leading to increased temperatures and material smearing. The heat dissipate role of fin was also observed during test where longer contact time of fin and abradable gives better heat removal performance.

Clearance and Seals Design for New Heat™ Steam Turbine

2006 ◽  
Author(s):  
Bernard A. Couture ◽  
Leslie B. Keeling ◽  
Mark W. Kowalczyk
Keyword(s):  
Steam Turbine ◽  
High Speed ◽  
High Efficiency ◽  
Labyrinth Seal ◽  
Mechanical Analysis ◽  
Advanced Technology ◽  
Speed Test ◽  
Steady State Operation ◽  
Thermal Mechanical Analysis ◽  
Abradable Coatings

The HEAT™ (High Efficiency Advanced Technology) steam turbine utilizes high reaction technology [1], which is significantly influenced by the effectiveness of sealing between the stages. The thermal-mechanical analysis based clearance design and the combination of labyrinth sealing with abradable coatings offer an effective solution to minimize bucket and nozzle tip leakage through transient and steady state operation of the turbine. The aim of this paper is to describe the clearance design process and the development of abradable-labyrinth seal configurations. The paper describes extensive testing and detailed analysis conducted to evaluate seal properties and behaviors. Properties investigated included corrosion, erosion and in particular, rub characteristics. Rub behavior is investigated in a high temperature, high speed test apparatus designed to simulate clearance changes during transient periods of start-up, shutdown and hot re-start which often result in interference between the sealing components. This paper will discuss the method to predict differential rotor to stator movements and the resulting abradable incursion during the various operating transients. The seal tooth to coating contact is then simulated with component testing for multiple incursion modes (i.e. radial, axial and a combination of the two) and rates. The discussion will also include the application of the clearance design and sealing technology to a reaction type steam turbine.

scholarly journals The Wear of Seal Fins during High-Speed Rub between Labyrinth Seal Fins and Honeycomb Stators at Different Incursion Rates

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 979
Author(s):  
Bin Lu ◽  
Xiaojian Ma ◽  
Caiguang Wu ◽  
Haijun Xuan ◽  
Weirong Hong
Keyword(s):  
Wear Mechanism ◽  
High Speed ◽  
Great Influence ◽  
Labyrinth Seal ◽  
Labyrinth Seals ◽  
Thermomechanical Stress ◽  
Delamination Wear ◽  
Metal Wear ◽  
Aero Engine ◽  
Worn Surface

Labyrinth seals as a noncontact sealing technology are widely used in aero-engine. To improve the efficiency of the aero-engine, the clearance between the rotor and stator must be as small as possible. However, the change of the clearance between the rotor and stator because of thermal expansion, vibration, mechanical loading may lead to undesirable high-speed rub, which will lead to the cracking of the seal fins. This paper focuses on the wear of the seal fin after the rub and presents the rubbing tests between seal fins and the metal honeycomb under rubbing speed of 380 m/s and incursion rates between 20 and 180 μm/s, with an incursion depth of 1500 μm and a temperature of 350 °C. The rubbing force and temperature were recorded, and the seal fins were checked by SEM and EDS. The results show that the wear mechanism of seal fins changed from oxidation wear and adhesive wear to delamination wear and then to metal wear with the increasing incursion rate. The axial cracks appeared on the worn surface of the seal fins due to the cracking of tribo-layers under periodic thermomechanical stress. The wear mechanism of the seal fin also has a great influence on the rubbing force and temperature.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

Integration of Self-diagnosis in Pascal Law Learning Using STEM Approach

2020 ◽  
Vol 12 (2) ◽  
pp. 104
Author(s):  
Siti Hannah Padliyyah
Keyword(s):  
International Student ◽  
Student Assessment ◽  
Active Role ◽  
Stem Learning ◽  
International Student Assessment ◽  
Science Technology ◽  
Engineering Mathematics ◽  
Post Test ◽  
11Th Grade

Indonesia is ranked 56th out of 65 participating countries in the Program for International Student Assessment (PISA) based on data 2015. According to PISA results, the average science score of Indonesian students is 403, where this number is categorized as low. This is because students are still in the process of understanding and have not yet fully recognized the location of their mistakes. Students can diagnose the location of their mistakes through self-diagnosis activities. Self-diagnosis activities require the active role of students during the learning process. One approach that can increase the active role of students is STEM (Science Technology Engineering Mathematics). However, research at this time is still rarely found self-diagnosis activities that are applied to the STEM approach. Therefore, this research has the aim to find out the increase in mastery of physical concepts and self-diagnosis of students on the STEM learning approach to the theory of poscal law class XI High School.This study uses a One-Group pretest-posttest design with a sample of 30 ini 11th grade highschool from one schools in Bandung. . Based on the findings, there is an increase in mastery of concepts [<g> = 0.51] from pre-test to post-test. In self-diagnosis activities identified that there are differences in scores [z = 1.75; p = 0.9599] student assessment results of researchers and self-scoring results. Deeper self-diagnosis triggers a series of implicit steps that encourage them to rearrange their cognition by correcting the mistakes they make when solving problems. So that learning activities using the STEM approach that involves self-diagnosis activities can improve students' mastery of concepts.

LANDSLIDE RISK MANAGEMENT IN THE COASTAL ZONE OF THE KUIBYSHEV RESERVOIR DUE THE DESIGN OF HIGH-SPEED LINE "MOSCOW-KAZAN"

2017 ◽  
Author(s):  
Nikolai Petrov ◽  
Nikolai Petrov ◽  
Inna Nikonorova ◽  
Inna Nikonorova ◽  
Vladimir Mashin ◽  
...  
Keyword(s):  
High Speed ◽  
Computational Models ◽  
Stable State ◽  
Landslide Risk ◽  
Kuibyshev Reservoir ◽  
Stepped Surface ◽  
The Stability ◽  
Landslide Slope ◽  
The Village

High-speed railway "Moscow-Kazan" by the draft crosses the Volga (Kuibyshev reservoir) in Chuvashia region 500 m below the village of New Kushnikovo. The crossing plot is a right-bank landslide slope with a stepped surface. Its height is 80 m; the slope steepness -15-16o. The authors should assess the risk of landslides and recommend anti-landslide measures to ensure the safety of the future bridge. For this landslide factors have been analyzed, slope stability assessment has been performed and recommendations have been suggested. The role of the following factors have been analyzed: 1) hydrologic - erosion and abrasion reservoir and runoff role; 2) lithologyc (the presence of Urzhum and Northern Dvina horizons of plastically deformable rocks, displacement areas); 3) hydrogeological (the role of perched, ground and interstratal water); 4) geomorphological (presence of the elemental composition of sliding systems and their structure in the relief); 5) exogeodynamic (cycles and stages of landslide systems development, mechanisms and relationship between landslide tiers of different generations and blocks contained in tiers). As a result 6-7 computational models at each of the three engineering-geological sections were made. The stability was evaluated by the method “of the leaning slope”. It is proved that the slope is in a very stable state and requires the following measures: 1) unloading (truncation) of active heads blocks of landslide tiers) and the edge of the plateau, 2) regulation of the surface and groundwater flow, 3) concrete dam, if necessary.

Therapeutic efficacy of Kantakari Ghrita in Tamaka Shwasa

2018 ◽  
Vol 3 (01) ◽  
Author(s):  
Dhanesh Kannan ◽  
Ravindra Angadi ◽  
Krishnendu O. Nambiar
Keyword(s):  
Marked Improvement ◽  
Signs And Symptoms ◽  
Unique Property ◽  
Test Design ◽  
Once Daily ◽  
Respiratory Condition ◽  
Post Test ◽  
Clinical Practise ◽  
Single Blind

Background: Ghrta Kalpana has a major role in clinical practise, because of its unique property of Samskarasya Anuvartanam. Tamaka Shwasa a Pranavaha Srothovikara, may be correlated to Bronchial Asthma, where in remissions and exacerbations are the typical features. The management of this acute respiratory condition is the long quest in the medical fraternity of all types. Hence, the present study was aimed to evaluate the role of Shamana therapy in the form of Kantakari Ghrta3 in Tamaka Shwasa patients. Objectives: To evaluate the effect of Kantakari Ghrta in Tamaka Shwasa. Methods: A total number of 30 patients were administered with 24 mgs of ‘Kantakari Ghrta’ once daily in the morning on empty stomach with Ushna Jala as Anupana. It was a single blind study with pre and post-test design. The effect was assessed by standard scoring assessment criteria followed by statistical analyses. Results: There was marked improvement in signs and symptoms and all were statistically significant. .

scholarly journals Crater wear mechanism of TiAlN coatings during high-speed metal turning

Wear ◽  
2021 ◽  
pp. 204016
Author(s):  
Maiara Moreno ◽  
Jon M. Andersson ◽  
Robert Boyd ◽  
Mats P. Johansson-Jöesaar ◽  
Lars J.S. Johnson ◽  
...  
Keyword(s):  
Wear Mechanism ◽  
High Speed ◽  
Crater Wear
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