Estimating velocity vectors in automotive injectors is primarily required for model validation purposes. Phase Doppler Anemometry has been used by several investigators to obtain time resolved velocities in GDI sprays.^1–3 In addition, high-speed videos have been used in the past to obtain plume penetration velocities as a function of time.^4–7 Extinction measurements at two heights have also been used to obtain plume velocities in GDI injectors.⁸ These imaging methods rely on using different types of edge detection methods to identify the variation in spray boundary as a function of time so as to obtain an approximate velocity. However, most of these methods are only applicable for the far-field spray behavior where the spray density is low. Particle imaging velocimetry (PIV) technique has been used to probe the internal structure of the sprays,^9,10 but its usefulness is limited to the far downstream region of the spray where the droplet density is relatively low so that images of the individual droplets can be resolved. The PIV technique will not provide reliable velocities if the particle image is not clearly resolved.¹¹

中文翻译：

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使用统计模式成像测速仪估算汽油直喷喷雾的速度

出于模型验证目的，主要需要估算汽车喷油器中的速度矢量。几位研究人员已使用相多普勒风速计来获得GDI喷雾器中时间分辨的速度。^1-3此外，过去使用高速视频来获取羽流穿透速度随时间的变化。^4–7在两个高度的消光测量也已用于获得GDI注射器中的羽流速度。⁸这些成像方法依赖于使用不同类型的边缘检测方法来识别喷雾边界随时间的变化，从而获得近似速度。但是，大多数这些方法仅适用于喷雾密度较低的远场喷雾行为。粒子成像测速（PIV）技术已用于探测喷雾的内部结构^9,10，但其用途仅限于喷雾密度相对较低的喷雾下游区域，因此单个液滴的图像可以得到解决。如果粒子图像无法清晰分辨，PIV技术将无法提供可靠的速度。¹¹