Temperature Measurement Method of Flame Image Fusion with Different Exposures

Fixed exposure will lead to underexposure or overexposure of collected flame radiation images using CCD, which has a great influence on the temperature measuring accuracy. A temperature measurement method was proposed by image fusion with multi-exposure, which can eliminate the influence of insufficient underexposure and overexposure. The approach was first to acquire a group of flame radiation images during different exposures. Then a partial region with good exposure effect in each radiation image was obtained by segmentation, with which the complete flame image can be spliced together. An experimental system was built to calibrate the temperature measurement parameters by two-color pyrometry through a blackbody furnace. The relation between exposure time and monochromatic gray level, as well as the relation between the temperature and temperature measurement coefficient were obtained. A candle flame was selected as the measuring object and the complete and accurate flame temperature distribution was acquired following our proposed method. The experimental results show that, compared with the temperature measurement using a single exposure time, our method can effectively avoid the measurement error caused by underexposure and overexposure, and improve the measurement accuracy.

Download Full-text

Turbine Blade Three-Wavelength Radiation Temperature Measurement Method Based on Reflection Error Correction

Applied Sciences ◽

10.3390/app11093913 ◽

2021 ◽

Vol 11 (9) ◽

pp. 3913

Author(s):

Kaifeng Zheng ◽

Jinguang Lü ◽

Yingze Zhao ◽

Jin Tao ◽

Yuxin Qin ◽

...

Keyword(s):

Temperature Measurement ◽

Turbine Blade ◽

Measurement Method ◽

Turbine Blades ◽

Target Surface ◽

Maximum Error ◽

Radiation Temperature ◽

Average Error ◽

Real Surface ◽

Wavelength Radiation

The turbine blade is a key component in an aeroengine. Currently, measuring the turbine blade radiation temperature always requires obtaining the emissivity of the target surface in advance. However, changes in the emissivity and the reflected ambient radiation cause large errors in measurement results. In this paper, a three-wavelength radiation temperature measurement method was developed, without known emissivity, for reflection correction. Firstly, a three-dimensional dynamic reflection model of the turbine blade was established to describe the ambient radiation of the target blade based on the real surface of the engine turbine blade. Secondly, based on the reflection correction model, a three-wavelength radiation temperature measurement algorithm, independent of surface emissivity, was proposed to improve the measurement accuracy of the turbine blade radiation temperature in the engine. Finally, an experimental platform was built to verify the temperature measurement method. Compared with three conventional colorimetric methods, this method achieved an improved performance on blade temperature measurement, demonstrating a decline in the maximum error from 6.09% to 2.13% and in the average error from 2.82% to 1.20%. The proposed method would benefit the accuracy in the high-temperature measurement of turbine blades.

Download Full-text

Experimental Study of Natural Gas Fuel Temperature Influence on Radiation Enhancement and Emission

ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, Volume 1 ◽

10.1115/esda2010-24486 ◽

2010 ◽

Author(s):

S. Mohammad Javadi ◽

Pourya Nikoueeyan ◽

Mohammad Moghiman ◽

M. Ebrahim Feyz

Keyword(s):

Radiation Intensity ◽

Flame Temperature ◽

Photovoltaic Module ◽

Exhaust Gas ◽

Gas Temperature ◽

Fuel Temperature ◽

Flame Radiation ◽

Exhaust Gases ◽

No Formation ◽

Exhaust Gas Temperature

The enhancement of the flame radiation in gas fueled burners not only improves the thermal efficiency, but also can suppress the rate of NO emission due to reducing the flame temperature. In this experimental investigation, the effect of inlet gas temperature on the flame radiation intensity and the rate of NO formation are studied. To serve this aim, with increasing the temperature of inlet methane to the burner up to 310°C, the variations of CO and NO level in exhaust gases and also the exhaust gas temperature are recorded by gas analyzer device. In each case, the flame radiation intensity was also measured by a photovoltaic module. The results revealed that by increasing the inlet gas temperature up to 250°C, the NO concentration and the exhaust gases temperature are raising. But when the inlet gas temperature exceeds from 250°C and reaches to 310°C, the flame luminosity gradually increases which results in 70 percent growth in flame radiation and 10 percent drop in exhaust gas temperature. The results of the preheating of inlet air also show the same behavior.

Download Full-text