Papers by Keyword: Spray Imaging

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Authors: Muhammad Yasin Naz, Shaharin Anwar Sulaiman, Bambang Ari-Wahjoedi, Ku Zilati Ku Shaari
Abstract: The use of starches as a material in urea granules coating industry is a recent development. The pure starches do not meet the standards set by many industrial processes due to slow tacking and to low viscosities, and require necessary modifications in their physical properties. The objective of the work was to synthesize and characterize the tapioca base biopolymers for future urea granules coating applications. For this purpose, three compositions of starch-urea-borate complex were prepared and their sprays were characterized using a bottom to top spraying system. The characterization of physical properties of the synthesized starch adhesives was carried out by determining the effect of temperature, shear rate and mass concentration of thickener/stabilizer on solution viscosity. A shear-thinning behavior followed by shear-thickening was observed for all solution compositions. This shear thinning to shear thickening transition becomes less prominent above 80°C of solution heating temperature. Using a high speed camera (Phantom v9.1), the jet breakup dynamics were also visualized as a function of the solution temperature and pumping pressure. . An increasing trend was noticed in spray cone angle with temperature upto 80°C and thereafter it became almost constant. Similarly, a linear increase in spray tip penetration was noticed with time from start of the injection which became steady after 70 ms of injection time.
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Authors: Muhammad Yasin Naz, Shaharin Anwar Sulaiman, Bambang Ari-Wahjoedi
Abstract: In this paper, an attempt was made to integrate the effect of jet injection time, load pressure and solution physical properties on jet breakup parameters. A starch-urea-borax complex solution was prepared and tested with an axi-symmetric full cone nozzle. The jet injection time was set to 100, 200, 300 and 400, the solution heating temperature was set to 20°C and 80°C ms, the load pressure was set to 1, 2, 3, 4, and 5 bar, and corresponding spray patterns were imaged by using a high speed camera. The imaging study of the developing spray patterns revealed that the unheated solution forms only spinning jets for all used load pressures. No jet breakup was seen in the near and far-nozzle imaged regions except at 5 bar load pressure, where minor spreading in the jet was seen after 80 mm downstream of the nozzle exit. At 80°C temperature and 5 bar load pressure, very dense spray patterns with an increased spray cone angle were emerging from the nozzle. After 300 ms of injection time, these developing spray jets were changed into fine spray patterns.
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Authors: Muhammad Yasin Naz, Shaharin Anwar Sulaiman, Bambang Ari-Wahjoedi
Abstract: The presented research work was focused onto the understanding of the jet behavior of the sprays of heated water during the low pressure atomization process. This task was accomplished using an in-house built intermittently forced liquid spraying system capable of lowering the liquid viscosity and surface tension to a desired value and then atomizing it into a full cone spray patterns in the ambient air surrounding. Using a high speed camera, the jet breakup dynamics were visualized as a function of system input parameters. The analysis of the grabbed images confirmed the strong influence of these processing parameters on full cone spray characteristics. It was also predicted that heated liquids generate a dispersed spray pattern by utilizing the partial evaporation of the spraying medium that is the induction of thermal energy enhances the jet disintegration ability. The spray cone width and angle did not vary significantly whereas the Weber and Reynolds numbers along with other nozzle flow parameters showed an appreciable response to the load pressure and temperature at early stages of water injection. The ultimate objective of the work was to understand and control the airless spray jet breakup mechanism under reduced load pressure and high water temperature.
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Authors: Muhammad Yasin Naz, Shaharin A. Sulaiman, Bambang Ari-Wahjoedi, Ku Zilati Ku Shaari
Abstract: The liquid jet breakup is a ubiquitous phenomenon in nature and a classic problem in hydrodynamics. The understanding of the jet breakup mechanism of hot liquids is still a challenge for researchers. The objective of this work was to understand and control the hot water spray jet breakup mechanism at moderate pumping pressures and elevated temperature. For this purpose, the visual and comparative studies were conducted on hollow cone water spray patterns generated by three hollow cone spray nozzles which were installed in an in-house built intermittently forced liquid spraying system. Using a high speed camera, the jet breakup dynamics were visualized as a function of system input parameters. The analysis of the grabbed images confirmed the strong influence of these processing parameters on spray characteristics. It was also predicted that heated liquids generate the dispersed spray patterns and the induction of thermal energy into the system enhances the jet disintegration ability. The spray cone width and angle were not varied significantly whereas the Weber and Reynolds numbers along with other spray parameters showed an appreciable response to the load pressure and water heating temperature at early stages of water injection.
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