scholarly journals Оцінка характеристик закапотованого гвинтовентилятора ТРДД з надвисоким сту-пенем двоконтурності

2021 ◽  
pp. 41-46
Author(s):  
Олеся Валеріївна Денисюк
Keyword(s):  
High Performance ◽  
Acoustic Radiation ◽  
Qualitative Assessment ◽  
Resistance Force ◽  
Flow Lines ◽  
Suction Force ◽  
Ducted Propeller ◽  
Direction Of Movement ◽  
Technical Solutions ◽  
Bypass Ratio

In many respects, the efficiency and economy of the aircraft are determined by the parameters and characteristics of the power plant. The analysis of trends in the world engine building shows that an increase in the bypass ratio can significantly increase the efficiency of engines. One of the possible technical solutions to ensure the high performance of the perspective engines with an ultra-high bypass ratio is the use of a ducted propeller or propfan. This solution allows you to reduce acoustic radiation. In addition, the main advantage of the ducted propfans is a certain increase in thrust for the same consumed power. When flowing around a ducted propfan, a significant suction force arises on the nose of the profiled ring, the projection of which on the direction of movement provides a positive thrust of the ring. The presence of a duct also leads to a decrease in the final loss of the propeller, which, in turn, leads to an increase in the efficiency of the engine. Ducted and unducted propfans with the same blade row are investigated to assess the characteristics of a ducted propfan. The researches were carried out by the method of numerical experiment. The object of the research is a propfan with an inlet diameter of 2.924 m and the number of blades of 14 for a turbofan engine with a bypass ratio of m = 30. To research the propfan characteristics, a cruising mode of operation was selected in the range of revolutions n = 1500 ... 1650 rpm. with Mach numbers at the input from M = 0.54 to M = 0.8. In this work, the calculation did not take into account the resistance force of the duct. For a qualitative assessment of the flow in the propfan, visualization of the flow lines in the ducted and unducted propfan was obtained. The analysis of the research results showed that for all modes of operation the ducted propfan has a thrust force higher than the unducted propfan. The increase in thrust load reaches 71 ... 76 %. Visualization of the flow lines when flowing around a ducted and unducted propfan showed that the presence of a duct improves the internal aerodynamics of the propfan.

scholarly journals Risk Assessment Framework to Avoid Serial Failure for New Technical Solutions Applied to the Construction of a CLT Structure Resilient to Climate

Buildings ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 247
Author(s):  
Charlotte Svensson Tengberg ◽  
Carl-Eric Hagentoft
Keyword(s):  
Risk Assessment ◽  
Success Factors ◽  
Real Life ◽  
Qualitative Assessment ◽  
Technical Solution ◽  
Functional Requirements ◽  
Assessment Framework ◽  
Construction Period ◽  
Design Build ◽  
Technical Solutions

Design-build contractors are challenged with the task of minimizing failure risks when introducing new technical solutions or adapting technical solutions to new conditions, e.g., climate change. They seem to have a disproportional trust in suppliers and their reference cases and might not have adequate resources or methodologies for sufficient evaluation. This creates the potential for serial failures to spread in the construction industry. To mitigate this, it was suggested that a predefined risk assessment framework should be introduced with the aim of providing a prequalification and requirements for the use of the technical solution. The objectives of this paper are to develop a comprehensive risk assessment framework and to explore the framework’s potential to adequately support the design-build contractor’s decisions. The framework uses qualitative assessment, relying on expert workshops and quantitative assessments, with a focus on simulation and probabilities. Tollgates are used to communicate risk assessments to the contractor. The framework is applied to a real-life case study of construction with a CLT-structure for a Swedish design-build contractor, where exposure to precipitation during construction is a key issue. In conclusion, the chosen framework was successful in a design-build contractor context, structuring the process and identifying difficulties in achieving the functional requirements concerning moisture. Three success factors were: documentation and communication, expert involvement, and the use of tollgates. Recommendations to the design-build contractor on construction of CLT structure are to keep construction period short and to use full weather protection on site.

scholarly journals Risks on Optimization of Life Cycle of Technology of Installation of Transformed Low-rise Buildings from Sandwich Panels

2018 ◽  
Vol 251 ◽  
pp. 06024 ◽  
Author(s):  
Alexander Pleshivtsev ◽  
Oleg Korol ◽  
Reza Barkhi
Keyword(s):  
Life Cycle ◽  
Industrial Production ◽  
High Performance ◽  
Technological Development ◽  
Sandwich Panels ◽  
Working Capital ◽  
Rapid Construction ◽  
Capital Efficiency ◽  
Technical Solutions

One of the main issues of development of organizational and technological solutions for the rapid construction of transformable low-rise buildings of sandwich panels (transformable low-rise buildings) is to improve the methods of industrial production through the use of high-performance mechanization. Increase of working capital efficiency, which makes prefabricated transformable buildings of sandwich panels the most attractive technical solutions for the investor-customer and allow you to quickly recoup the investment. Traditional measures of improvement of the organization of processes and specific directions of development of the organization of construction production of (transformable low-rise buildings) in modern conditions are given. We highlight the technological component of sustainability, and the specifics of security in the modern conditions of technological development and increasing innovativeness.

scholarly journals Advanced high-performance concrete structures - challenge for sustainable and resilient future

2018 ◽  
Vol 195 ◽  
pp. 01001
Author(s):  
Petr Hajek
Keyword(s):  
High Performance ◽  
High Performance Concrete ◽  
Concrete Structures ◽  
Potential Contribution ◽  
Basic Principles ◽  
Model Code ◽  
Existing Structures ◽  
Impact Reduction ◽  
Development Goals ◽  
Technical Solutions

Development and recent changes in natural and socio-economic environment requires new technical solutions for construction of new and reconstruction and modernization of existing structures. Structures and all built environment should be better prepared for new conditions - they should be sustainable and resilient. Concrete is building material with high potential for new technical solutions resulting in needed environmental impact reduction and consequent social and economic improvements. The paper presents potential contribution of concrete industry, advanced highperformance concrete and concrete structures to Sustainability Development Goals specified in UN 2030 Agenda for Sustainable Development and presents basic principles of implementation of sustainability approach into design of concrete structures and particularly to fib Model Code 2020.

Fabrication of High Aspect Ratio Microcoils Using X-Ray Lithography

2010 ◽  
Author(s):  
Daiji Noda ◽  
Masaru Setomoto ◽  
Tadashi Hattori
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
High Performance ◽  
Three Dimensional ◽  
Fabrication Process ◽  
Electromagnetic Actuators ◽  
Pipe Surface ◽  
Suction Force ◽  
X Ray ◽  
Micro Parts

Recently, the demand of micro-fabrications such as micro-sensors, microcoils, micro-actuators etc is increasing. Actuators account for a large percentage and volume and weight of a product compared with other parts. Therefore, the progress in downsizing of actuators was required. In order to resolve these problems, the key technology to realizing micro-devices is micro-fabrication process. Particularly, it is essential to the technologies for processing high aspect ratio structures in the production of micro-parts. We have proposed a three-dimensional fabrication process using X-ray lithography technique, and fabricated spiral microcoils having coil lines of narrow pitch and high aspect ratio structures. We have fabricated spiral microcoils at a pitch of 60 μm, and aspect ratio of about 5 using X-ray lithography and narrow metallization techniques on acrylic pipe surface. In addition, we also estimated the suction force of electromagnetic actuators using these microcoils. Measurement results were relatively in good agreement with theoretical values using high aspect ratio microcoils. It is very expected that the high performance microcoils could be manufactured in spite of miniature size.

Key Technologies Research of New Generation Concentrating Photovoltaic

2013 ◽  
Vol 724-725 ◽  
pp. 171-175
Author(s):  
Chun Tong Liu ◽  
Li Bing ◽  
Wang Tao ◽  
Hong Cai Li
Keyword(s):  
High Performance ◽  
Tracking System ◽  
Research Process ◽  
Photovoltaic System ◽  
Core Technology ◽  
Key Technologies ◽  
High Conversion Rate ◽  
The Cost ◽  
Technical Solutions ◽  
New Generation

The new concentrating photovoltaic (CPV) with core technology of III-V multi-junction cells, can significantly reduce the cost of photovoltaic system, and with advantages of high conversion rate, light weight, small size, energy saving and environmental protection, etc, which was widely regarded as the next-generation of solar photovoltaic technology. On the basis of the introduction of related research process, the paper concentrating discuss on the key technologies such as the new efficient multi-junction cells, high performance non-imaging concentrated light technology and sun tracking system, and propose the appropriate technical solutions, which can provide reference for the application and dissemination of the new generation concentrating photovoltaic.

scholarly journals TFE1042: A New Low Bypass Ratio Engine

1990 ◽  
Author(s):  
A. R. Finkelstein
Keyword(s):  
United States ◽  
High Performance ◽  
Development Program ◽  
The United States ◽  
Light Weight ◽  
United States Military ◽  
Bypass Ratio

The TFE1042-70 is a modern low-bypass ratio afterburning military engine for light-weight fighters and high performance trainers. Designed, developed, and qualified in the 1980’s, it is intended to power the latest aircraft in the 1990’s and beyond. A version without the afterburner has been given the United States Military Engine designation of F124-GA-100. The engine is rugged, compact, durable, and easily maintained. It has been designed to meet the latest U. S. Military specification standards. This paper describes the engine and the development program.

Airframe/Propulsion Integration at Transonic Speeds

1990 ◽  
Author(s):  
William P. Henderson
Keyword(s):  
High Performance ◽  
Propulsion System ◽  
Research Center ◽  
Thrust Vectoring ◽  
Mach Numbers ◽  
Langley Research Center ◽  
Bypass Ratio ◽  
High Performance Aircraft

A significant level of research is ongoing at NASA’s Langley Research center on integrating the propulsion system with the aircraft. This program has included nacelle/pylon/wing integration for turbofan transports, propeller/nacelle/wing integration for turboprop transports, and nozzle/afterbody/empennage integration for high performance aircraft. The studies included in this paper focus more specifically on pylon shaping and nacelle bypass ratio studies for turbofan transports, nacelle and wing contouring and propeller location effects for turboprop transports, empennage effects, and thrust vectoring for high performance aircraft. The studies were primarily conducted in NASA Langley’s 16-Foot Transonic Tunnel at Mach numbers up to 1.20.

A New Stretching Process: Slant Forging Method

2011 ◽  
Vol 181-182 ◽  
pp. 113-117
Author(s):  
Li Yong Ni ◽  
Suo Qing Yu ◽  
L. Li ◽  
S.Y. Zhu ◽  
Hua Gui Huang
Keyword(s):  
Mechanical Properties ◽  
Finite Element Method ◽  
High Performance ◽  
Flow Direction ◽  
Metal Flow ◽  
Production Costs ◽  
Flow Lines ◽  
Forging Process ◽  
Stretching Process ◽  
Selection Of

High transversal properties requirements of heavy axial forgings, traditionally, often are met through the selection of high-performance materials, the improvement of metallurgical quality and repeated forging. But the production costs and power consumption are both high. A new slant forging method is adopted, by controlling the metal flow direction in forgings, to achieve the increase of transversal mechanical properties. Finite element method was applied to study the influence of forging process parameters on flow lines in axial forgings, providing theoretical guidance for the eventual realization of the forging method.

Sign in / Sign up

Export Citation Format

Share Document