【摘要】 在垂直自由下降液膜试验台上,利用CCD(Charge Coupled Device)的图像快速采集功能,获得了不同雷诺数下自由下降液膜流的瞬时流态图像,并用图像处理方法对这些原始图像进行计算机数字化处理。研究了某一区域内瞬时液膜厚度沿流向演化特征和某一位置上液膜厚度随时间的演化特征,并给出了不同雷诺数下平均液膜厚度和雷诺数间的实验关联式。实验结果表明:在雷诺数小于4000时测量精度较准,在雷诺数大于4000时,由于采样设备的影响,误差较大。本文实现了液膜流动特征的无接触测量,为数字图像处理技术应用到薄膜流动特性研究方面做出了有益的尝试。更多还原

【Abstract】 On a vertical free-falling liquid-film test rig,by employing the image rapid-acquisition function of a CCD (Charge Coupled Device),the transient flow-pattern images of a free-falling liquid-film flow at different Reynolds numbers were obtained and then digitally processed on a computer by using an image processing method.Studied were the evolution characteristics of the transient liquid-film thickness along the flow direction in a certain zone and the time-dependent evolution characteristics of the above thickness at a certain location.Also given was an experimental formula showing the correlation of the average liquid film thickness with Reynolds numbers under the condition of different Reynolds numbers.The test results show that the measurement accuracy is comparatively high when the Reynolds number is less than 4000 and the measurement error is relatively big when the Reynolds number is over 4000 due to the influence of sampling facilities.The authors have undertaken a non-contact measurement of flow characteristics of liquid films,initiating a useful attempt for applying digital image processing technology to the study of thin-film flow characteristics.更多还原