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Quantitative measurement of hydroxyl radical(OH) concentration in premixed flat flame by combining laser-induced fluorescence and direct absorption spectroscopy 下载免费PDF全文
An accurate and reasonable technique combining direct absorption spectroscopy and laser-induced fluorescence(LIF)methods is developed to quantitatively measure the concentrations of hydroxyl in CH_4/air flat laminar flame. In our approach, particular attention is paid to the linear laser-induced fluorescence and absorption processes, and experimental details as well. Through measuring the temperature, LIF signal distribution and integrated absorption, spatially absolute OH concentrations profiles are successfully resolved. These experimental results are then compared with the numerical simulation. It is proved that the good quality of the results implies that this method is suitable for calibrating the OH-PLIF measurement in a practical combustor. 相似文献
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采用近似方法计算了CO分子的总配分函数;利用该分子的偶极矩函数和在Morse近似下的波函数,计算了分子的振转跃迁矩阵元及在常温和高温下的吸收系数。计算结果表明,在常温(296 K)和高温下(3 000 K),计算结果与HITRAN数据库和文献值符合的很好,表明对分子总配分函数和振转跃迁矩阵元的计算是可靠的。并首次计算了CO分子在更高温度(4 000和6 000 K)下的吸收系数。 相似文献
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Noninvasive technology for measuring instantaneously two-dimensional(2D) temperature distributions of flame using two-color planar laser induced fluorescence(PLIF) of OH is investigated.A calibration method is researched and developed.This method is based on the calibration experiments with a laminar premixed flame and thermocouple,and avoids complex calculation and uncertainty of the spectrum parameters.Measurements for a flat burner at ambient temperature under atmospheric pressure are also presented;calibration results are used to diagnose a supersonic combustion in scramjet combustor.The conclusion indicates that this method is useful,and a better precision of calibration can be acquired by correcting the line shapes of the spectral lines and lasers. 相似文献
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Numerical analysis of quantitative measurement of hydroxyl radical concentration using laser-induced fluorescence in flame 下载免费PDF全文
The aim of the present work is to quantitatively measure the hydroxyl radical concentration by using LIF(laserinduced fluorescence) in flame.The detailed physical models of spectral absorption lineshape broadening,collisional transition and quenching at elevated pressure are built.The fine energy level structure of the OH molecule is illustrated to understand the process with laser-induced fluorescence emission and others in the case without radiation,which include collisional quenching,rotational energy transfer(RET),and vibrational energy transfer(VET).Based on these,some numerical results are achieved by simulations in order to evaluate the fluorescence yield at elevated pressure.These results are useful for understanding the real physical processes in OH-LIF technique and finding a way to calibrate the signal for quantitative measurement of OH concentration in a practical combustor. 相似文献
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High sampling-rate measurement of turbulence velocity fluctuations in Mach 1.8 Laval jet using interferometric Rayleigh scattering 下载免费PDF全文
Interferometric Rayleigh scattering diagnostic technique for the time-resolved measurement of flow velocity is studied. Theoretically, this systematic velocity-measured accuracy can reach up to 1.23 m/s. Measurement accuracy is then evaluated by comparing with hot wire anemometry results. Moreover, the distributions of velocity and turbulence intensity in a supersonic free jet from a Laval nozzle with a Mach number of 1.8 are also obtained quantitatively. The sampling rate in this measurement is determined to be approximately 10 k Hz. 相似文献
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