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Article
Publication date: 14 September 2015

Chuanjun Liao, Xibao Xu, Hongrong Fang, Hongrui Wang and Man Man

The purpose of this paper is to develop a leakage model of metallic static seals, which can be used to accurately predict the leakage rate and study the corresponding seal

Abstract

Purpose

The purpose of this paper is to develop a leakage model of metallic static seals, which can be used to accurately predict the leakage rate and study the corresponding seal characteristics. The metallic static seal is effectively applied to severe rugged environments where conventional seals cannot meet the needs. More research efforts for deepening the understanding of its seal characteristics are important for its effective and safe applications, of which the study about its leak is one key component.

Design/methodology/approach

In the microscopic observations of the turning surface that is general in the processing of flange surfaces, it is found that the spiral morphology is dominant, which had been also obtained by other researches. There are two potential leakage paths for the flange surface of spiral morphology, one is the radial direction perpendicular to the spiral ridges and the other is the circumferential direction along the spiral groove. Based on the microgeometry characteristics of spiral morphology, the micromorphology of turning flange surface is simplified for the calculation of leakage rate, and the simplified methods of the radial and circumferential leakage paths are presented separately. The topography of flange surface studied in this paper is actually measured, and the Abbott bearing surface curve is adopted to represent the micro-profiles parameters. The radial and circumferential leakage models are further developed based on the assumption of laminar flow of the viscous compressible gas.

Findings

The experiments used to verify the leakage models were carried out, and the experimental values are well agreed with the calculated values. As the contact pressure increases, the change rules of both radial and circumferential leakage rates are obtained and the obvious transition from radial leak to circumferential leak can be found. Using the proposed leakage models, the effects of the key micro-profiles parameters on the leakage rates are studied, and some specific conclusions are given simultaneously, which are favorable for the theoretical study and practical application of the metallic static seal.

Practical implications

By the interpretations of the micromorphology characteristics of turning flange surface, the leakage mechanism of the metallic static seal is further made clear. The proposed leakage model reveals the relationships between the key micro-profiles parameters and some sealing performances about the leakage and can predict the leakage rates of the metallic static seal used in various working conditions.

Originality/value

For the metallic static seal, the simplification of the radial leakage path and the radial leakage model are put forward for the first time, so the total leakage model can be systematically reported based on the micromorphology characteristics of turning flange surface. The effects of the key micro-profiles parameters on the seal behaviors including of the leak rate, critical contact pressure and transition from radial leak to circumferential leak etc are also clarified firstly.

Details

Industrial Lubrication and Tribology, vol. 67 no. 6
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 February 1959

In introducing the subject some of the advantages of pneumatics for high speed aircraft are pointed out. Owing to its suitability for airborne conditioning systems, it is pointed…

Abstract

In introducing the subject some of the advantages of pneumatics for high speed aircraft are pointed out. Owing to its suitability for airborne conditioning systems, it is pointed out that it is logical to combine this characteristic in producing a combined air turbine and electric generator without the need of a separate cooling system. This was the thought behind the design of the Turbonator AC generating machine It includes a turbine wheel integral with the generator which is arranged to allow the turbine exhaust gas to pass over the generator for cooling purposes. The generator rotor windings are supported solidly by titanium retainers. Rotor bearings may either be of the sealed oil type or air bearings. Both have been tested, but, while the former is the simplest and suitable for present‐day standards, the air bearing has distinct possibilities for future uses. Thrust loads are taken up by an air bearing using the turbine wheel face as the bearing journal. No liquid is therefore used as a lubricant, thereby eliminating this high temperature problem. Materials for the generator are considered, one of which is ceramic insulation. Consideration was given to the inductor generator, but although this type of machine may be more suitable for high speeds, the rotating winding generator displays more advantages. A test rotor of the latter type has withstood speeds of 62,000 r.p.m. which is 25 per cent above normal speeds. The recent availability of a 24,000 r.p.m. generator makes it possible to eliminate a reduction gear.

Details

Aircraft Engineering and Aerospace Technology, vol. 31 no. 2
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 December 1987

Highly accurate data on ground and weather conditions in the immediate vicinity are supplied by the new ‘Weathermate’ portable weather station from Vicon Ltd.

Abstract

Highly accurate data on ground and weather conditions in the immediate vicinity are supplied by the new ‘Weathermate’ portable weather station from Vicon Ltd.

Details

Aircraft Engineering and Aerospace Technology, vol. 59 no. 12
Type: Research Article
ISSN: 0002-2667

Article
Publication date: 1 September 1999

Jaroslav Mackerle

This paper gives a review of the finite element techniques (FE) applied in the analysis and design of machine elements; bolts and screws, belts and chains, springs and dampers…

4353

Abstract

This paper gives a review of the finite element techniques (FE) applied in the analysis and design of machine elements; bolts and screws, belts and chains, springs and dampers, brakes, gears, bearings, gaskets and seals are handled. The range of applications of finite elements on these subjects is extremely wide and cannot be presented in a single paper; therefore the aim of this paper is to give FE researchers/users only an encyclopaedic view of the different possibilities that exist today in the various fields mentioned above. An Appendix included at the end of the paper presents a bibliography on finite element applications in the analysis/design of machine elements for 1977‐1997.

Details

Engineering Computations, vol. 16 no. 6
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 5 March 2020

Fei Lu, Jian Liu and Hongyan Lu

The carbon/carbon (C/C) composite finger seal experiment was performed on a high-speed seal tester. The purpose of this paper is to investigate the leakage and wear…

Abstract

Purpose

The carbon/carbon (C/C) composite finger seal experiment was performed on a high-speed seal tester. The purpose of this paper is to investigate the leakage and wear characteristics of C/C composite finger seal under various operating conditions.

Design/methodology/approach

Static, dynamic, endurance and post endurance tests were carried out. For static and performance tests, the pressure differential changed from 0.1 to 0.6 MPa and the rotor speed varied from 1,000 to 9,000 r/min. Two endurance tests were conducted for 4 h, with each mounting two finger seals. The seal leakage was monitored by mass flowmeters, and the wear depth was measured and calculated by using three-dimensional profilometer.

Findings

Results showed that the seal leakage increases with pressure differential but decreases with rotor speed. Leakage rate is lower when speed is decelerated than that with the speed stepped up. During a time history, material removal caused by wear has significant influence on leakage data causing higher leakage than the results before endurance test. Particular interest is that the uneven wear characteristic on finger foot bottom was firstly revealed, showing severe wear in foot heel area than that in foot toe.

Originality/value

This study could provide experimental guidance for finger seal designers. Additionally, the uneven wear characteristic of finger foot was firstly revealed, which showed the necessity of further theoretical research on finger seal wear.

Details

Industrial Lubrication and Tribology, vol. 72 no. 10
Type: Research Article
ISSN: 0036-8792

Keywords

Article
Publication date: 1 August 1999

Jaroslav Mackerle

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper…

2604

Abstract

This paper gives a bibliographical review of the finite element methods (FEMs) applied to the analysis of ceramics and glass materials. The bibliography at the end of the paper contains references to papers, conference proceedings and theses/dissertations on the subject that were published between 1977‐1998. The following topics are included: ceramics – material and mechanical properties in general, ceramic coatings and joining problems, ceramic composites, ferrites, piezoceramics, ceramic tools and machining, material processing simulations, fracture mechanics and damage, applications of ceramic/composites in engineering; glass – material and mechanical properties in general, glass fiber composites, material processing simulations, fracture mechanics and damage, and applications of glasses in engineering.

Details

Engineering Computations, vol. 16 no. 5
Type: Research Article
ISSN: 0264-4401

Keywords

Article
Publication date: 1 May 1959

E.G. Ellis

ON December 20th, 1910, Mr. E. W. Dunne, the inventor of the arrow‐headed, tail‐less, twin screw biplane, made an experimental flight which deserves greater recognition than it…

Abstract

ON December 20th, 1910, Mr. E. W. Dunne, the inventor of the arrow‐headed, tail‐less, twin screw biplane, made an experimental flight which deserves greater recognition than it has perhaps received. In order to demonstrate the inherent stability of the design, he flew a circuit at Eastchurch “hands‐off” while writing his observations of its behaviour. To do this he provided the controls with a set of locking levers designed to give a small number of set positions to correspond with turns, climbing, etc. The test was completely successful and Mr. Dunne returned safely to terra‐firma albeit this was the first time that he had turned this particular machine at any height !

Details

Industrial Lubrication and Tribology, vol. 11 no. 5
Type: Research Article
ISSN: 0036-8792

Content available
Article
Publication date: 1 March 2006

35

Abstract

Details

Pigment & Resin Technology, vol. 35 no. 2
Type: Research Article
ISSN: 0369-9420

Keywords

Article
Publication date: 1 May 1960

KENNETH R. BOREHAM

HOW OFTEN does one hear the aggrieved tones of a sufferer asking why he must put up with leakage troubles ? All too frequently such situations occur in all of the very many…

Abstract

HOW OFTEN does one hear the aggrieved tones of a sufferer asking why he must put up with leakage troubles ? All too frequently such situations occur in all of the very many branches of hydraulics and it seems a pity that in many instances the trouble need not have occurred at all. Obviously, the art of scaling is far from perfect and, in fact, this branch of technology is undergoing some fairly radical development at the present time. Nevertheless, although seals are a necessary evil, many of the occasions when seal trouble is experienced could have been averted if the correct seal had been chosen in the first place and then used to the best advantage.

Details

Industrial Lubrication and Tribology, vol. 12 no. 5
Type: Research Article
ISSN: 0036-8792

Article
Publication date: 9 March 2010

Włodzimierz Ochoński

The purpose of this paper is to present short characteristics of shape memory alloys (SMA) and shape memory polymers (SMP) and some examples of application of these materials in…

2679

Abstract

Purpose

The purpose of this paper is to present short characteristics of shape memory alloys (SMA) and shape memory polymers (SMP) and some examples of application of these materials in industrial sealing technology.

Design/methodology/approach

In this paper, short characteristic of shape memory materials and design examples of applying them in industrial sealing technology such as: tube coupling in hydraulic systems, flanged pipe connections, lip radial seal, mechanical face seal, soft gland packing, magnetic fluid seal, and in bearing seal system for drill bit, are given.

Findings

The paper provides information about innovative fluid seal designs based on particular properties of the shape memory materials, applied in stationary joints, and rotary equipments. These new solutions provide often to simplify seal design, their miniaturization, increase of tightness, and reduction of operating costs.

Originality/value

This paper offers some new fluid seal designs based on the shape memory materials and their practical application in industrial sealing technology.

Details

Industrial Lubrication and Tribology, vol. 62 no. 2
Type: Research Article
ISSN: 0036-8792

Keywords

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