عنوان مقاله [English]
This study investigates the performance of two-fluid nozzle. The nozzle type is automatic pneumatic, which works by air pressure and flow rate and is used mainly in spray and coating systems in drug industries. Nozzle characteristics has determined by the image processing method. At first, the spray is photographed by a digital camera and then the desired images are modified and prepared for processing by MATLAB software. The results presented by means of the photography method include angle of spray. Furthermore, spray volume is calculated according to air and liquid flow rate variances. The results indicate that increasing air flow rate has a greater impact on the spray angle than increasing the liquid flow rate. Also, by changes in the ratio of air and liquid flow rate, spray angle can change. It also shows that the effect of air flow rate in the process of droplet atomization in the spray is much greater than the impact of liquid flow rate. In addition, a pneumatic two-fluid nozzle used in pharmaceutical industry and fluid bed dryers was investigated, because the spray angel and operating conditions are very important to produce the desired product.