Detection method of combustion oscillation characteristics under strong noise background

2020 ◽  
Vol 21 (6) ◽  
pp. 612
Author(s):  
Yunkun Wei ◽  
Tianhong Zhang ◽  
Zhonglin Lin ◽  
Qi Xie ◽  
Yan Zhang
Keyword(s):  
Radiation Thermometry ◽  
Hydroxyl Group ◽  
Interference Signal ◽  
Engine Vibration ◽  
Combustion Technology ◽  
Lean Fuel ◽  
Combustion Oscillation ◽  
Aero Engines ◽  
Temperature Measurement System ◽  
Multispectral Radiation Thermometry

After the lean fuel premixed combustion technology is applied to aero engines, severe combustion oscillations will be cased and led to hidden safety hazards such as engine vibration, further energy waste and other problems. Therefore, it is increasingly important to actively control combustion oscillations. In this paper, a multispectral radiation thermometry (MRT) is used to analyze the hydroxyl group, which is a measurable research object in the combustion chamber of an aero engine, and to fit the functional relationship between the radiation intensity ratio and the temperature in different bands. The theoretical value of the error is <2%. At the same time, in order to solve the problem of weak detection signal and excessive interference signal, an improved frequency domain filtering method based on fast Fourier transform is designed. Besides, the FPGA platform is used to ensure the real-time performance of the temperature measurement system, and simulations and experiments are performed. An oscillating signal with an oscillation frequency of 315 Hz is obtained on the established test platform, and the error is only 1.42%.

An Undergraduate Industrial Design Exercise at Rolls-Royce plc

2006 ◽  
Author(s):  
G. D. Lock ◽  
M. Child ◽  
V. Cheng ◽  
R. Johnson ◽  
W. Mezzullo ◽  
...  
Keyword(s):  
Rotor Dynamics ◽  
Design Tool ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Engine Vibration ◽  
Previous Design ◽  
Undergraduate Programme ◽  
Aero Engines ◽  
The University ◽  
Related Design

The Department of Mechanical Engineering at the University of Bath has been conducting an undergraduate engine-related design exercise at Rolls-Royce, Bristol since 2000. Each year a team of six undergraduates complete an engine-related design project under supervision from the company between February and September. This work is coordinated and assessed at both the company and university, and counts overall as 20% of the student’s four-year degree. In addition to working at Rolls-Royce, the students submit reports and give seminars at the university. The design exercise is predominantly technical in nature but must include a significant business element. The students are paid as company employees, typically £7.2k for the six months. This paper describes the design exercise and how it is accommodated into the undergraduate programme of study at the University of Bath. The benefits to the university, the students and the company are discussed. In addition, the six students undertaking the 2005 exercise describe their projects. This year there were three projects, two of which were continuations from previous design exercises. The three projects are listed below. Aero-Engine Rotor-Dynamics (V Cheng and S Peet): An experimental and computation study of engine vibration using a rotor-dynamics rig, simulating the engine. The aim was to assess the accuracy and improve the modeling techniques used at Rolls-Royce. Implementing Design for Environment on Gas turbine engines using a Design Tool (W Mezzulo): A study to create a tool to enable the designer to evaluate the environmental aspects of the life of an engine component. Aero-thermodynamics of aero-engines (M Child, R Johnson and C Pattinson): Various design aspects of aero-engines, both computational and business. Note that M Child’s project is not discussed here for reasons of Rolls-Royce proprietary and confidentiality.

Experimental Investigation of Emissivity of Aluminum Alloys and Application of Multispectral Radiation Thermometry

2010 ◽  
Author(s):  
Chang-Da Wen
Keyword(s):  
Aluminum Alloys ◽  
Temperature Measurement ◽  
Radiation Thermometry ◽  
Surface Oxidation ◽  
Spectral Emissivity ◽  
Absolute Temperature ◽  
Real Surface ◽  
Emissivity Model ◽  
Higher Temperature ◽  
Multispectral Radiation Thermometry

Experiments were first conducted to measure the spectral normal emissivity values of a variety of aluminum alloys at 600, 700, and 800 K. Multispectral radiation thermometry (MRT) using linear emissivity models (LEM) and log-linear emissivity models (LLE) were then applied to predict surface temperature. Results show that the spectral emissivity decreases with increasing wavelength and increases with increasing temperature. Alloy effect becomes evident at higher temperature. The surface oxidation becomes fully-developed after the first hour heating and results in constant emissivity. Half of temperature predictions by MRT emissivity models provide the absolute temperature error under 10% and a quarter if the results are under 5%. The better emissivity model to suitably represent the real surface emissivity behaviors the more accurate inferred temperature by MRT can be achieved. Increasing the order of emissivity model and increasing the number of wavelengths cannot improve temperature measurement accuracy. More accurate temperature measurement by MRT can be achieved at higher temperature. Overall, three emissivity models give good results most frequently and provide the best compensation for different alloys, the number of wavelengths, and temperatures.

Rotordynamic Analysis Method of Small Turbo-Fan Engine Based on Finite Element Models

2010 ◽  
Author(s):  
Jie Hong ◽  
Meng Chen ◽  
Yanhong Ma ◽  
Liming Zhang
Keyword(s):  
Sensitivity Analysis ◽  
High Speed ◽  
Relative Sensitivity ◽  
Vibration Modes ◽  
Coupled Modes ◽  
Critical Speeds ◽  
Compressor Rotor ◽  
Engine Vibration ◽  
Rotor Support ◽  
Aero Engines

Small size, light weight and high speed are remarkable characteristics of modern small aero-engines. The rotor components of engine are always series connected by spline joints or face tooth joints, so dynamic interaction of different rotor components have to be taken into account in aero-engine vibration analysis. Firstly, a modal analysis of the integral series connected rotor is performed as well as the analysis of each rotor components including fan rotor, compressor rotor and turbo rotor. The result captures the effects of the rotor components on the integral rotor, the modes of the integral rotor are composed of the modes of the rotor components and the coupled modes of them. Secondly, one special characteristic of this rotor is that No.3, 4, and 5 compressor disks and compressor shaft is interference connected initially. Based on calculation of connecting state, two models of the compressor rotor are presented, including a model with connecting state effects and a general model without connecting state effects, and a rotordynamic analysis is performed with the two models. The effect of the connecting state between shaft and disks of compressor rotor on rotordynamics is captured, as well as the true critical speeds and vibration modes. Thirdly, due to different assembly state and variable mechanical force, typical parameters which affect rotordynamics directly, such as rotor support stiffness and joints structure stiffness are not constant. A sensitivity analysis of critical speeds and vibration modes with respect to typical parameters (joints structure stiffness) is performed with finite difference method, two approaches are carried out, including relative sensitivity analysis and absolute sensitivity analysis. The effect of the parameters on rotordynamics is captured, as well as the variation range of critical speed. Finally, the analysis of test data validates the author’s method.

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