摘要
环形空气进口能够显著强化低速喷雾干燥器的干燥阶段。更精确一点,加入环形喷射进口能够延长有效干燥时间,但不能提高干燥速度。计算流体动力学分析进一步表明这是因为同轴环形被加热射流内部的"弯曲",导致在喷嘴雾化器下部区域产生明显的穿流和逆流。对大液滴干燥这种改善更加明显。以此构想为基础,在莫纳什大学开发了一种空气室原型,使得同轴环形射流用于低速喷雾塔中。此样机成功将酪蛋白、脱脂牛奶和乳糖溶液喷雾干燥成自由流动粉体。
Annulus air inlet was found to significantly intensify the drying period of low velocity spray dryers. To be more precise, incorporation of the annulus jet inlet prolonged the effective drying period but does not increase the drying rate. Computational fluid dynamics analysis further showed that this is due to the inwards ＇bending＇ of the concentric annulus heated jet which resulted in apparent cross flows and counter current flows in the region below the nozzle atomizer. This improvement in drying is particularly significant for larger droplets. Based on this concept, a prototype air plenum chamber was built which allowed concentric annulus jets to be used on the low velocity spray tower in Monash. The prototype was successfully tested with casein, skim milk and lactose solutions, spray dried into free flowing powders.
基金
2011年新员工研究基金
