Third Paper: The Behaviour of Lubricated Steel Balls under Close-Conformity Aero-Engine Mainshaft Ball Race Conditions

1970 ◽  
Vol 185 (1) ◽  
pp. 373-381 ◽  
Author(s):  
D. J. Haines
Keyword(s):  
Electrical Conductance ◽  
Point Of View ◽  
Operating Conditions ◽  
Wide Field ◽  
Major Purpose ◽  
Arbitrary Boundary ◽  
Aero Engine ◽  
Race Conditions ◽  
Wear Damage ◽  
Steel Balls

The behaviour of individual ball to track contact areas is studied in close conformity oil lubricated conditions. Although primarily concerned with aero-engine operating conditions the results are expressed in dimension-less forms which permit use over a wide field of ball race geometries. An arbitrary boundary is established, based upon electrical conductance through the oil film, between running conditions which produce minimal wear damage and conditions which are probably unacceptable from this point of view. The major purpose of the paper is to focus attention on this criterion and to relate ball to track kinematic situations to it.

Tertiary Nitrification Pilot Plants on Parisian Waste Water

1990 ◽  
Vol 22 (1-2) ◽  
pp. 347-352 ◽  
Author(s):  
C. Paffoni ◽  
B. Védry ◽  
M. Gousailles
Keyword(s):  
Waste Water ◽  
Metropolitan Area ◽  
Fixed Bed ◽  
Point Of View ◽  
Operating Conditions ◽  
Research Center ◽  
Daily Output ◽  
Practical Point ◽  
Fixed Bed Reactors

The Paris Metropolitan area, which contains over eight million inhabitants, has a daily output of about 3 M cu.meters of wastewater, the purification of which is achieved by SIAAP (Paris Metropolitan Area Sewage Service) in both Achères and Valenton plants. The carbon pollution is eliminated from over 2 M cu.m/day at Achères. In order to improve the quality of output water, its tertiary nitrification in fixed-bed reactors has been contemplated. The BIOFOR (Degremont) and BIOCARBONE (OTV) processes could be tested in semi-industrial pilot reactors at the CRITER research center of SIAAP. At a reference temperature of 13°C, the removed load is approximately 0.5 kg N NH4/m3.day. From a practical point of view, it may be asserted that in such operating conditions as should be at the Achères plant, one cubic meter of filter can handle the tertiary nitification of one cubic meter of purified water per hour at an effluent temperature of 13°C.

Unsteady simulations of migration and deposition of fly-ash particles in the first-stage turbine of an aero-engine

2021 ◽  
pp. 1-21
Author(s):  
Z. Hao ◽  
X. Yang ◽  
Z. Feng
Keyword(s):  
Fly Ash ◽  
Film Cooling ◽  
Particle Deposition ◽  
Flow Characteristics ◽  
Leading Edge ◽  
Velocity Model ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Internal Cooling ◽  
Aero Engine

Abstract Particulate deposits in aero-engine turbines change the profile of blades, increase the blade surface roughness and block internal cooling channels and film cooling holes, which generally leads to the degradation of aerodynamic and cooling performance. To reveal particle deposition effects in the turbine, unsteady simulations were performed by investigating the migration patterns and deposition characteristics of the particle contaminant in a one-stage, high-pressure turbine of an aero-engine. Two typical operating conditions of the aero-engine, i.e. high-temperature take-off and economic cruise, were discussed, and the effects of particle size on the migration and deposition of fly-ash particles were demonstrated. A critical velocity model was applied to predict particle deposition. Comparisons between the stator and rotor were made by presenting the concentration and trajectory of the particles and the resulting deposition patterns on the aerofoil surfaces. Results show that the migration and deposition of the particles in the stator passage is dominated by the flow characteristics of fluid and the property of particles. In the subsequential rotor passage, in addition to these factors, particles are also affected by the stator–rotor interaction and the interference between rotors. With higher inlet temperature and larger diameter of the particle, the quantity of deposits increases and the deposition is distributed mainly on the Pressure Side (PS) and the Leading Edge (LE) of the aerofoil.

ADVANCED TYPES OF CHECKERWORK OF REGENERATIVE HEAT EXCHANGERS FOR GLASS FURNACES

2021 ◽  
pp. 3-10
Author(s):  
O. Koshelnik ◽  
S. Hoisan
Keyword(s):  
Phase Transition ◽  
Heat Exchangers ◽  
Heat Storage ◽  
Point Of View ◽  
Operating Conditions ◽  
Flue Gases ◽  
Regenerative Heat ◽  
Exchange Processes ◽  
Glass Furnaces ◽  
Refractory Bricks

One of the ways to increase glass furnaces energy efficiency is to apply heat exchangers for flue gases thermal potential utilization. Flue gases losses is up to 25-40 % of the total amount of heat supplied in the furnace. These losses are influences by such factors as fuel type, furnace and burners design and manufactured product type. Regenerative heat exchangers with various types of heat storage packing is more efficient for high-power furnaces. Such types of regenerator checkerwork as Cowper checkerwork, two types of Siemens checkerwork, Lichte checkerwork and combined checkerwork have already been sufficiently researched, successfully applied and widely used for glass furnaces of various designs. All of its are made of standard refractory bricks. Basket checkerwork and cruciform checkerwork that are made of fused-cast molded refractory materials have been widely used recently as well. Further improvement of regenerative heat exchangers thermal efficiency only by replacing the checkerwork does not seem possible unless their size being increased. But this enlarging is not always realizable during the modernization of existing furnaces. From this point of view heat storage elements with a phase transition, where metal salts and their mixtures are used as a fusible agent look promising for glass furnaces. These elements can accumulate additional amount of heat due to phase transition, which allows to increase significantly heat exchanger thermal rating without its size and operating conditions changing. However, it is necessary to carry out additional studies of this type of checkerwork dealing with analysis of complex unsteady heat exchange processes in regenerators and selection of appropriate materials that satisfy the operating conditions of regenerative heat exchangers so that the checkerwork can be widely used for glass furnaces.

Some Possible Lines of Development in Aircraft Engines

1921 ◽  
Vol 25 (123) ◽  
pp. 130-165
Keyword(s):  
Present State ◽  
State Of The Art ◽  
Point Of View ◽  
Aircraft Engines ◽  
Aero Engine ◽  
The Ideal

In the following paper the writer's aim is to indicate certain possible lines of development and research which his own investigations and preliminary experiments have shown to be at least worthy of serious consideration.If we review the present state of the art we find the position to be substantially as follows :—From a thermodynamic point of view the performance of the modern aero engine has approached so nearly to the ideal obtainable from the cycle on which it operates that there is little scope for improvement.

Towards Improved Prediction of Aero-Engine Combustor Performance Using Large Eddy Simulations

2008 ◽  
Author(s):  
S. James ◽  
M. S. Anand ◽  
B. Sekar
Keyword(s):  
Gas Turbine ◽  
Radial Profile ◽  
Design Tool ◽  
Operating Conditions ◽  
Outlet Temperature ◽  
Gas Turbine Combustor ◽  
Systematic Assessment ◽  
Eddy Simulation ◽  
Large Eddy ◽  
Aero Engine

The paper presents an assessment of large eddy simulation (LES) and conventional Reynolds averaged methods (RANS) for predicting aero-engine gas turbine combustor performance. The performance characteristic that is examined in detail is the radial burner outlet temperature (BOT) or fuel-air ratio profile. Several different combustor configurations, with variations in airflows, geometries, hole patterns and operating conditions are analyzed with both LES and RANS methods. It is seen that LES consistently produces a better match to radial profile as compared to RANS. To assess the predictive capability of LES as a design tool, pretest predictions of radial profile for a combustor configuration are also presented. Overall, the work presented indicates that LES is a more accurate tool and can be used with confidence to guide combustor design. This work is the first systematic assessment of LES versus RANS on industry-relevant aero-engine gas turbine combustors.

scholarly journals STATE ANALYSIS INTERNET OF THINGS DEVICES BASED ON BAGGING

T-Comm ◽  
2020 ◽  
Vol 14 (12) ◽  
pp. 45-50
Author(s):  
Mikhail E. Sukhoparov ◽  
◽  
Ilya S. Lebedev ◽  
Keyword(s):  
Time Series ◽  
Internet Of Things ◽  
The State ◽  
Point Of View ◽  
Operating Conditions ◽  
Process Time ◽  
K Nearest Neighbors ◽  
Computational Point ◽  
Iot Devices ◽  
The Internet Of Things

The development of IoT concept makes it necessary to search and improve models and methods for analyzing the state of remote autonomous devices. Due to the fact that some devices are located outside the controlled area, it becomes necessary to develop universal models and methods for identifying the state of low-power devices from a computational point of view, using complex approaches to analyzing data coming from various information channels. The article discusses an approach to identifying IoT devices state, based on parallel functioning classifiers that process time series received from elements in various states and modes of operation. The aim of the work is to develop an approach for identifying the state of IoT devices based on time series recorded during the execution of various processes. The proposed solution is based on methods of parallel classification and statistical analysis, requires an initial labeled sample. The use of several classifiers that give an answer "independently" from each other makes it possible to average the error by "collective" voting. The developed approach is tested on a sequence of classifying algorithms, to the input of which the time series obtained experimentally under various operating conditions were fed. Results are presented for a naive Bayesian classifier, decision trees, discriminant analysis, and the k nearest neighbors method. The use of a sequence of classification algorithms operating in parallel allows scaling by adding new classifiers without losing processing speed. The method makes it possible to identify the state of the Internet of Things device with relatively small requirements for computing resources, ease of implementation, and scalability by adding new classifying algorithms.

scholarly journals Coordinating activity of independent legal entities: issues of law enforcement in conditions of economy digitalization

2019 ◽  
pp. 60-67
Author(s):  
Yu. Yu. Borisova ◽  
I. V. Akimova
Keyword(s):  
Law Enforcement ◽  
Economic Activity ◽  
Legal Regulation ◽  
Point Of View ◽  
Operating Conditions ◽  
Negative Effects ◽  
Judicial Practice ◽  
Stage Of Development ◽  
Legislative Changes ◽  
The Coordinator

In article authors investigate questions of the operating legal regulation of coordination of economic activity of independent economic entities, including questions of its legisla- tive definition and signs. Article contains the detailed analysis of the most interesting examples of judicial practice and practice of antimonopoly authorities on the matter. Authors, analyzing the current legal regulation, also give an assessment to the planned changes in the legislation in this part and state the point of view about dependence of legal assessment of actions of the coordinator and the economic entities coordinated by it on operating conditions of commodity markets on which it is carried out. As a result of a research authors drew a conclusion on need of legislative changes in a part of admis- sibility of the forbidden coordination provided that the advantage for consumers of such coordination exceeds negative effects for the competition.A significant amount of works of the modern scientists and experts investigating a per- spective of institutes of the antitrust law is devoted to questions of legal qualification of coordination of economic activity of independent economic entities in legal scientific literature.The matter was also raised in publications and authors of the "Rossiyskoye Konkurent- noye Pravo I Ekonomika" magazine, at the same time, it should be noted that to consid- eration of questions of coordination of activity smaller attention is paid, than, for ex- ample, to questions of cartels.Thus, degree of scientific readiness of the matter in general is rather high, at the same time to authors the relevance of this subject and need of the analysis and assessment of the operating regulation taking into account economic features of the present stage of development of the markets seems to be of high interest.

scholarly journals Tools for Developing a Regional Education Development Strategy

2021 ◽  
pp. 110-121
Author(s):  
Yu. N. Lapygin ◽  
S. A. Boltunov
Keyword(s):  
Development Strategy ◽  
Education System ◽  
General Scheme ◽  
Intermediate Stage ◽  
Comprehensive Analysis ◽  
Strategy Implementation ◽  
Point Of View ◽  
Instrumental Support ◽  
Wide Field ◽  
Education Development

The framework structure of the federal law on strategic planning leaves a wide field of activity for developers to use various tools in the process of building a development strategy for both the region and its sub-systems, which include the education system of the region. The methodological recommendations of the Ministry of Economic Development of the Russian Federation regarding the development of a strategy specify only the content of the main directions of the strategy, but allow the use of various methods, models and mechanisms for developing the strategy itself. Therefore, the study of the issues of instrumental support of procedures for developing strategies for regions and its subsystems is of interest from a theoretical and practical point of view.In the study of theoretical and applied problems of instrumental support of the process of developing a strategy, algorithms are built in the form of a general scheme for developing a strategy and performing a comprehensive analysis prior to development. Algorithms for developing a strategy at the initial stage were formed based on the results of a comprehensive analysis, at the stage focused on the main goal (Mission), as well as at the final stage, the goals of which are focused on the ideal state in the future — Vision. Besides. An algorithm for determining the expected results has been built. on the basis of which a scenario for the development of regional subsystems is built.The scientific novelty of the developed procedures lies in the fact that a set of tools for determining strategically significant projects and programs of the final and intermediate stages of strategy implementation is proposed; tools for agreeing strategically significant decisions were formed throughout the cycle of strategic development of the region’s education system; shows the procedure for constructing a tree of goals for the intermediate stage of the strategy implementation; a procedure for the formation of a development strategy at the intermediate stage of strategy implementation has been developed. The proposed approach to building a strategy for the development of socio-economic systems in the region is implemented in the process of adjusting the development strategy of the Vladimir region in terms of vocational education in the region.

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