【摘要】 对基于热辐射测量喷涂粒子速度、温度的检测系统,建立了单窗调制光阑下的信号演变过程模型,提取了4种基本信号特征类型,发现只有曲边梯形信号可准确测量粒子速度、温度与尺寸等状态参数,而其他类型信号的出现将增加测量误差.用超音速火焰喷涂实验验证表明,实测信号特征与理论模型分类基本相符,瞄准距离与孔径光阑直径对信号特征影响显著,减小孔径光阑直径可降低非曲边梯形信号引入的测量误差,但也会导致信号强度和捕获粒子总数的下降.更多还原

【Abstract】 Using a single-window modulating aperture, a theoretical model for the evolution of radiant pulse signal is proposed, which is suitable for the measurement system based on thermal radiation to diagnose velocity and temperature of spray particles. According to the geometrical characteristics of signals, the four types of characteristic signals are defined. It reveals that only the signal in curve-sided trapezoid shape with a saturated flat top can be used to measure reliably parameters of spray particles. The error in measured parameters of particles will be induced by the occurrence of other types of signals. The experiment results obtained using high velocity oxy-fuel spray process show that the measured signals present the characteristics predicted theoretically. The characteristics are significantly influenced by aiming distance and diameter of aperture diaphragm. The decrease in the diameter of aperture diaphragm leads to the decrease in measurement error of particle parameters, as well as in the amplitude of signal and the number of captured particles.更多还原