Thermographic particle velocimetry (TPV) for simultaneous interfacial temperature and velocity measurements
Thermographic particle velocimetry (TPV) for simultaneous interfacial temperature and velocity measurements
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DOI：
10.1016/j.ijheatmasstransfer.2016.02.050
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发表时间：
2016-06
影响因子：
5.2
通讯作者：
A. Charogiannis;Ivan Zadrazil;C. Markides
中科院分区：
文献类型：
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作者：
A. Charogiannis;Ivan Zadrazil;C. Markides
我们提出了一种实验技术，称为“热成像粒子测速”（TPV），它能够同时测量多相流界面处的二维（2-D）表面温度和速度。该技术的发展源于研究倾斜加热基底上重力驱动液膜流的需要，然而，相同的测量原理可以应用于在两个流体相之间具有足够密度梯度的任何流的界面处恢复二维温度场和速度场信息。所提出的技术依赖于单个红外（IR）成像仪，并基于高反射（此处为镀银）颗粒的使用，当这些颗粒悬浮在界面附近或界面处时，由于其不同的发射率，可以与周围的流体域区分开来。用于恢复温度和速度分布的图像处理步骤包括将每个原始原始红外图像分解为单独的热图像和粒子图像，应用透视畸变校正和空间校准，最后实施标准粒子测速算法。通过将该技术应用于开放容器中的加热和搅拌流来演示该过程。此外，还提出了两项验证实验，一项专门用于测量界面温度，一项专门用于测量界面速度。 TPV 生成的结果与伴随的传统技术生成的结果之间的偏差不超过与后者相关的误差。
We present an experimental technique, that we refer to as ‘thermographic particle velocimetry’ (TPV), which is capable of the simultaneous measurement of two-dimensional (2-D) surface temperature and velocity at the interface of multiphase flows. The development of the technique has been motivated by the need to study gravity-driven liquid-film flows over inclined heated substrates, however, the same measurement principle can be applied for the recovery of 2-D temperature- and velocity-field information at the interface of any flow with a sufficient density gradient between two fluid phases. The proposed technique relies on a single infrared (IR) imager and is based on the employment of highly reflective (here, silver-coated) particles which, when suspended near or at the interface, can be distinguished from the surrounding fluid domain due to their different emissivity. Image processing steps used to recover the temperature and velocity distributions include the decomposition of each original raw IR image into separate thermal and particle images, the application of perspective distortion corrections and spatial calibration, and finally the implementation of standard particle velocimetry algorithms. This procedure is demonstrated by application of the technique to a heated and stirred flow in an open container. In addition, two validation experiments are presented, one dedicated to the measurement of interfacial temperature and one to the measurement of interfacial velocity. The deviations between the results generated from TPV and those from accompanying conventional techniques do not exceed the errors associated with the latter.