Investigation on the Applicability of the Effervescent Atomizer in Spray Drying of Foods: Influence of Liquid Viscosity on Nozzle Internal Two‐Phase Flow and Spray Characteristics
Investigation on the Applicability of the Effervescent Atomizer in Spray Drying of Foods: Influence of Liquid Viscosity on Nozzle Internal Two‐Phase Flow and Spray Characteristics
复制标题
泡腾雾化器在食品喷雾干燥中的适用性研究：液体粘度对喷嘴内部两相流和喷雾特性的影响
DOI：
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发表时间：
2015
期刊：
影响因子：
--
通讯作者：
H. Schuchmann
中科院分区：
文献类型：
--
作者：
P. Stähle;V. Gaukel;H. Schuchmann
研究了食品基模型液体的粘度对雾化器内流型及喷雾的影响。粘度范围为0.001 ~ 0.308 Pa·s。随着液体体积流量的增加，液体粘度增加，雾化器内的流型从环形变为不利的弹状流。我们使用时间平均的Sauter平均直径（SMD）以及时间离散的液滴尺寸在其平均值附近的波动κt来表征喷雾。对于环状流，SMD和κt的值很小，与粘度无关;但随着流型转变为弹状流，SMD和κt显著增加。研究结果表明，将喷雾雾化原理应用于食品喷雾干燥，需要雾化器内部具有特定的流型。
实际应用
最初在燃烧科学领域发明的雾化器，据报道能够以低气体消耗将具有高粘度的液体雾化成小滴。这些属性使得雾化原理对于其他技术（例如食品的喷雾干燥）也是有意义的。如果实施是可能的，雾化技术提供了在低气体消耗下干燥具有高粘度的进料的潜力。这反过来又为食品喷雾干燥开辟了两种新的可能性：第一，通过更高浓度的进料节省干燥能量，第二，防止热敏成分受损，因为与传统的雾化器相比，可以选择雾化前较低的进料温度。不幸的是，一个不稳定的喷雾在某些操作条件下的报告。在这种情况下，应用程序可能会受到限制。
The influence of viscosity of a food-based model liquid on the flow patterns inside an effervescent atomizer as well as on the spray was investigated. Viscosity ranged from 0.001 to 0.308 Pa·s. The flow pattern inside the atomizer changes from annular to an unfavorable slug flow for liquids with increased viscosity with increasing liquid volume flow rate. We used the time averaged Sauter mean diameter (SMD) as well as the fluctuation κt of the time-discrete drop size around its mean to characterize the spray. For an annular flow, small values of SMD and κt are observed regardless of viscosity; but as the flow pattern transforms to slug flow, a considerable increase of SMD and κt is observed. The results indicate that the application of the effervescent atomizing principle to the tasks of food spray drying requires a specific flow pattern inside the atomizer.
Practical Application
The effervescent atomizer, originally invented in the field of combustion science, is reported to be capable of atomizing liquids with elevated viscosity into small drops at low gas consumption. These attributes make the atomizing principle also interesting for other techniques such as the spray drying of foods. If an implementation is possible, the atomization technique offers the potential of drying feeds with high viscosity at low gas consumption. This, in turn, opens two new possibilities in spray drying of foods: first, to save drying energy via a higher concentrated feed and, second, to prevent heat-sensitive ingredients from damage because a lower feed temperature prior to atomization could be chosen compared with conventional atomizers. Unfortunately, an unsteady spray is reported for certain operation conditions. In this case, an application is likely to be limited.
聚乙烯吡咯烷酮溶液的泡腾雾化：液体特性和雾化器几何形状对液体分解和喷雾特性的影响
影响因子：
1.2
作者：
Schröder;Günther;Schuchmann;Gaukel
通讯作者：
Gaukel