Study of primary atomisation phenomenon of modified starch solution stream at elevated temperature

• Published in: Materials research innovations 2014-12, Vol.18 (sup6), p.S6-135-S6-139
• Main Authors: Naz, M. Y., Sulaiman, S. A., Ariwahjoedi, B., Ku Shaari, K. Z.
• Format: Article
• Language: English
• Subjects: Biopolymers; Jet breakup; Phase doppler anemometry; Spray imaging; Tapioca starch
• ISSN: 1432-8917; 1433-075X
• DOI: 10.1179/1432891714Z.000000000944

The objective of the work was to study the primary atomisation phenomenon of the starch-urea-borate complex solutions at elevated temperature. Firstly, the dynamic viscosity and surface tension of the solutions were studied as a function of temperature and applied shear rate. Secondly, using a high-speed camera (Phantom v9·1) and phase Doppler anemometry, the jet breakup dynamics, Sauter mean diameter and droplet velocity vectors were studied. A shear-thinning behaviour followed by shear thickening was observed for all solution compositions. The surface tension was decreased concomitantly with an increase in solution temperature. However, an increasing trend in a spray cone angle was noticed when solution temperature was elevated up to 80°C. The phase Doppler anemometry studies revealed that at 80°C solution temperature and 1·5 bar load pressure, the spray droplets start getting uniform sizes and move in random directions at 120 cm downstream of the nozzle exit.