Combinations of We, Re and Ohnesorge Oh numbers defined the droplet maximum spread factor, the number of secondary droplets generated as a result of the splashing process and the transition between the different impact outcomes. These criteria can then be used in field scale spray deposition and drift models to better understand agricultural spray operations.
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Issue 34, Previous Article Next Article. From the journal: Soft Matter. With these effects it is important to note that measuring obstacles placed within these flows such endoscopes may not see a true depiction of the flow properties. This study looks at the effects of droplet size caused by the intrusive obstacle using DIA techniques. Experimental setup: The DIA technique is based on the extraction of information from the digital images. In order to acquire these images, several components or equipments have been utilised.
The following sub-topics describe the function of each component and also explain about the DIA system setup. Components of the DIA system: There was three main components used in the development of DIA system and they included a laser, a digital camera and a computer Fig.
All these components were integrated to make the whole systems work. Besides that, a software program was developed using LabView codes in order to perform automated image processing and analysis tasks. In the development of DIA system Fig. A proper amount of light was necessary so that a good quality of drops images can be achieved. The maximum output of the laser was around mJ and it produced a pulsed beam with a nm in wavelength.
A pulsed beam was critical for fast moving droplets and desirable even for slow moving fluid. The laser beam was converted to a laser cone using a concave lens, and then it was diffused by a diffuser.
Droplets and Sprays : Saptarshi Basu :
This trigger signal was used to synchronise the detection of the digital camera. Digital camera was used to capture shadow images of the droplets which were back-lighted by the diffused light. The DIA technique was applied to process and analyse the images to determine droplet size distribution in real-time using custom developed software. It equipped with IEEEb connectors to allow high image transfer speed.
This monochrome camera has a resolution up to x pixels. It also has an ability to receive an external triggering signal for synchronization with the pulsed laser. The purpose of DIA system was to characterise small particles or droplets in the range of micron sizes.
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Thus, it was important to have a higher magnification of image. Therefore, a mm micro-lens equipped with a spacer or bellow were used in this study. As a result, field of view FOV of the image with a resolution of x pixels was at 1.
The optical configuration of this current setup has produced a magnification factor of 2. The DIA system was equipped with a computer for controlling the laser and the camera. The developed software was installed in this computer and used as a platform for synchronisation between the pulsed laser and the camera. A monitor of the computer was used to display on-line results. These results were obtained from the developed software where the software automatically processed and analysed the acquired images and plotted them into graphs.
- ISBN 13: 9781447163855.
- Droplets and Sprays.
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- Droplet size measurements;
Working principle of the DIA system: In this experiment, the DIA system was applied to perform an on-line characterisation of spray droplets. A schematic diagram of the system setup was depicted in Fig. A computer was used to send commands to the laser to fire the beam at required light intensity.
The commands were written using Hyperterminal windows program and sent to a laser power supply via serial RS cable. Once the commands were entered, the pulsed beam was fired from the laser unit and converted to laser cone by a concave lens. The repetition rate and duration of this pulsed were about 0. The droplets were back-lighted with a light source and the camera acquired the shadow image of the drops in a sequence of frames.
This signal was then triggered the camera to acquire a raw image of the drops. The resolution of acquired image was at x pixels.
Combustion of Droplets and Sprays of Some Alternative Fuels
The working distance between the drops and a focal lens was about mm. The image was then directly transferred from the camera to a memory of computer via IEEEb FireWire cable for instant processing. The image was processed and analysed using the developed software in order to obtain the droplet size distribution and the mean size. Digital image processing and analysis: The DIA technique was applied to extract valuable information from an image.
Once the raw image was received by the software, it was processed to enhance its appearance and then analysed to extract the desired information such as a number of pixels occupied by a single droplet. The developed software was produced using a LabView platform. The flowchart of the algorithms was outlined in Fig. After image acquisition, the first processing stage was image enhancement.