A Low Noise Propulsion Concept for the Supersonic Transport

1991 ◽  
Author(s):  
G. A. Champagne ◽  
G. E. Allen ◽  
M. Palmieri ◽  
R. M. Adler
Keyword(s):  
High Speed ◽  
Thermal Noise ◽  
Noise Suppression ◽  
Low Noise ◽  
Environmental Standards ◽  
Supersonic Transport ◽  
Engine Design ◽  
Exhaust Jet ◽  
Propulsion Concept ◽  
Jet Velocities

The major challenges with the design of propulsion systems for High speed Civil Transports (HSCT) are complying with FAR and EPA environmental standards while powering an economically acceptable aircraft. These issues create a dilemma in engine design because low exhaust jet velocities are required to meet takeoff noise regulations while high exhaust jet velocities are required for economical supersonic cruise operation. Previous studies have shown that to meet FAR Stage 3 noise regulations, engines incorporating mechanical/thermal noise suppression concepts must be oversized by 50 to 80% relative to the size that will provide the maximum aircraft economics. In order to achieve the Stage 3 noise levels without oversizing the engine, the engine airflow must be increased by 120% during takeoff operation to reduce the average exhaust velocity to an acceptable level. This paper will examine a concept that brings in 74% additional airflow into the engine’s inlet and 46% into the engine’s exhaust nozzle. The impacts of this concept on engine design, performance, size and weight and on aircraft takeoff gross weight (TOGW) and range are evaluated. For the same TOGW aircraft, this noise reduction concept provides a 70% range improvement relative to engines which incorporate mechanical/thermal noise suppressors. This concept was developed under a NASA sponsored program.

scholarly journals Conceptual Design of Turbo-Accelerator for HST Combined Cycle Engine

1992 ◽  
Author(s):  
R. Yanagi ◽  
M. Morita ◽  
Y. Watanabe ◽  
H. Itahara ◽  
Y. Sasaki ◽  
...  
Keyword(s):  
Conceptual Design ◽  
High Speed ◽  
Low Noise ◽  
Combined Cycle ◽  
Propulsion System ◽  
Supersonic Transport ◽  
Low Pressure Turbine ◽  
Ramjet Engine ◽  
Speed Range ◽  
Jet Velocity

Hypersonic Transport Propulsion System Research (HYPR) Project was started in 1900 to develop technologies for the propulsion system of a Mach 5 Hypersonic Civil Transport, which could be environmentally acceptable and economically viable. The engine being studied is the methane fueled combined cycle engine composed of a turbo-accelerator for low speed range and a ramjet engine for high speed range. what is called a turbo/ramjet engine. The turbo-accelerator is required to meet the low noise regulations at take-off and achieve high specific thrust at high speed flight like the second generation SST (Supersonic Transport) engine. The single bypass turbofan engine (SBE) with variable cycle concept was selected as the turbo-accelerator engine to meet the above requirements in one engine. The engine was conceived to have variable geometry in compressor stator, low pressure turbine stator, fan bypass flow nozzle aren and exhaust nozzle area for low jet velocity at take-off and high jet velocity at altitude high speed and be equipped with a mixer ejector in the exhaust nozzle for further noise reduction. This paper describes the cycle study and conceptual design of the demonstrator of a turbo-accelerator engine being planned to be tested in 1903.

scholarly journals Research on Performance Test System of Space Harmonic Reducer in High Vacuum and Low Temperature Environment

Machines ◽  
2020 ◽  
Vol 9 (1) ◽  
pp. 1
Author(s):  
Jing Wang ◽  
Zhihua Wan ◽  
Zhurong Dong ◽  
Zhengguo Li
Keyword(s):  
Low Temperature ◽  
High Speed ◽  
Performance Test ◽  
High Reliability ◽  
High Vacuum ◽  
Test System ◽  
Low Noise ◽  
Speed Ratio ◽  
Space Harmonic ◽  
Temperature Environment

The harmonic reducer, with its advantages of high precision, low noise, light weight, and high speed ratio, has been widely used in aerospace solar wing deployment mechanisms, antenna pointing mechanisms, robot joints, and other precision transmission fields. Accurately predicting the performance of the harmonic reducer under various application conditions is of great significance to the high reliability and long life of the harmonic reducer. In this paper, a set of automatic harmonic reducer performance test systems is designed. By using the CANOpen bus interface to control the servo motor as the drive motor, through accurately controlling the motor speed and rotation angle, collecting the angle, torque, and current in real time, the life cycle test of space harmonic reducer was carried out in high vacuum and low temperature environment on the ground. Then, the collected data were automatically analyzed and calculated. The test data of the transmission accuracy, backlash, and transmission efficiency of the space harmonic reducer were obtained. It is proven by experiments that the performance data of the harmonic reducer in space work can be more accurately obtained by using the test system mentioned in this paper, which is convenient for further research on related lubricating materials.

Simulation of jet velocity in the melt-blowing process using the coupled air–polymer model

2018 ◽  
Vol 89 (16) ◽  
pp. 3221-3233 ◽  
Author(s):  
Xibo Hao ◽  
Hui Huang ◽  
Yongchun Zeng
Keyword(s):  
High Speed ◽  
Flow Model ◽  
Processing Parameters ◽  
High Speed Photography ◽  
Critical Factors ◽  
Polymer Model ◽  
Melt Blowing ◽  
Two Phase ◽  
Jet Velocity ◽  
Jet Velocities

The polymer jet velocity is one of the most basic and critical factors in the melt-blowing process and has always been difficult to measure online. Much effort has been made on the numerical prediction of the jet velocity. However, little work has involved the complex interaction between the air flow and the polymer. Here, the Level-Set method is used to develop the coupled air–polymer two-phase flow model, and to simulate the polymer jet motion in the melt-blowing process considering the coupled effect of the air and polymer. Meanwhile, high-speed photography is adopted in the experiments to verify the simulation results. The x- and y-components of the jet velocities and the whipping amplitude of the jet motion are discussed. The rapid increase of jet velocity and the decrease of jet diameter show that most attenuation of the polymer jet occurred within a distance close to the die (10 mm). Based on the model, the effects of the processing parameters on the jet velocity are examined numerically.

scholarly journals Development of intelligent preamplifier for semiconductor detectors

2021 ◽  
pp. 8-8
Author(s):  
Vladimir Kondratjev ◽  
Vasily Litvinsky ◽  
Serhii Pohuliai ◽  
Stanislavs Lozkins
Keyword(s):  
Liquid Nitrogen ◽  
High Speed ◽  
Temperature Sensors ◽  
Low Noise ◽  
Nitrogen Level ◽  
Semiconductor Detectors ◽  
Resistive Feedback ◽  
Charge Sensitive Preamplifier ◽  
Gamma Detectors

The results of engineering an intelligent preamplifier for HPGe gamma-detectors are presented. An intelligent preamplifier is a low-noise, high-speed resistive feedback charge-sensitive preamplifier with a built-in microcontroller and additional units that enable control of preamplifier and detector parameters. It also allows to manage performance of the internal testing pulser, sensor of liquid nitrogen level in Dewar, humidity, pressure and temperature sensors in a sealed preamplifier section. Intelligent preamplifier operation, setup and parameter measurements are controlled by a software.

Propelling Nozzle Research

1964 ◽  
Vol 68 (647) ◽  
pp. 717-727 ◽  
Author(s):  
W. G. E. Lewis
Keyword(s):  
High Speed ◽  
High Performance ◽  
Research Programme ◽  
Static Tests ◽  
Transport Aircraft ◽  
Supersonic Transport ◽  
Design Behaviour ◽  
Base Bleed ◽  
Critical Phases ◽  
The Ideal

SummaryThe current interest in supersonic transport aircraft makes it appropriate to consider the problems of propulsion nozzle systems for high speed flight. The discussion will be confined mainly to this field of activity.In the absence of external drag and weight factors, the ideal configuration to maintain optimum thrust at all flight speeds would employ a mechanically variable area ratio nozzle. By such means the jet flow could be fully and properly expanded at all times.A practical design to accommodate such variations is inherently complex, and so an alternative solution using aerodynamic techniques has been sought. It is necessary to remember that the success of whatever method is eventually chosen must rest on its ability to combine a high performance at cruise with very small loss during other critical phases of the flight plan.This paper describes some of the results of a nozzle research programme aimed primarily at solving the above problem, with an attempt to explain the philosophy behind the aerodynamic techniques tried. Some discussion is given of the experimental difficulties in establishing a sufficiently accurate standard of measurement for design point performance. In a few chosen configurations experimental results have been extensively backed by theoretical studies.The need to demonstrate off-design behaviour in the presence of an external flow field is stressed, with special reference to the misleading results often obtained from static tests.Finally, some attention is given to the question of base bleed, with its repercussions on the installation of the propulsion nozzle in an aircraft.

A Low-Noise Design Technique for High-Speed CMOS Optical Receivers

2014 ◽  
Vol 49 (6) ◽  
pp. 1437-1447 ◽  
Author(s):  
Dan Li ◽  
Gabriele Minoia ◽  
Matteo Repossi ◽  
Daniele Baldi ◽  
Enrico Temporiti ◽  
...  
Keyword(s):  
High Speed ◽  
Low Noise ◽  
Optical Receivers ◽  
Design Technique ◽  
Low Noise Design
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