Experimental Investigation of Emissivity of Aluminum Alloys and Temperature Determination Using Multispectral Radiation Thermometry (MRT) Algorithms

2002 ◽  
Vol 11 (5) ◽  
pp. 551-562 ◽  
Author(s):  
Chang-Da Wen ◽  
Issam Mudawar
Keyword(s):  
Experimental Investigation ◽  
Aluminum Alloys ◽  
Radiation Thermometry ◽  
Temperature Determination ◽  
Multispectral Radiation Thermometry

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.

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%.

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