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Xin Yi Ong

Postgraduate Research Student
+44 (0)1483 684601
34 BC 02

Academic and research departments

Department of Chemical and Process Engineering.

My publications


Ong X, Taylor SE, Ramaioli M (2017) The effect of interfacial properties and liquid flow on the
stability of powder islands,
EPJ Web of Conferences 140 EDP Sciences
This study aims at understanding the interplay between the interfacial properties of the powder grains and the characteristics of the liquid flow used to disperse them, in order to obtain an effective dispersion of a powder in a liquid, avoiding air entrainment. The dispersion of grain ?rafts? and powder islands ?stacks? was investigated both on a static and on a moving air-liquid interface. Powder wicking prevents the formation of a powder island when the grain contact angle is below a critical contact angle. Above the critical contact angle, a powder island forms and grows to a critical depth that depends on grain radius and contact angle. Imposing a flow on the air-liquid interface can either promote water impregnation, reducing the depth of the powder island or destabilise the whole island. In the latter case, the island sinks, forming a heterogeneous powder structure that is wet outside and dry inside.
Ong X, Taylor S, Ramaioli M (2017) Rehydrating Food Powders and Avoiding Lumps: Effect of
Powder Properties and Liquid Flow,
Chemical Engineering Transactions. ISBN 978-88-95608- 48-8 57 pp. 1939-1944 The Italian Association of Chemical Engineering
Poor dispersion of beverages from dehydrated powders is a defect that obstructs the development of novel
dehydrated food powders. We investigate how the physico-chemical properties of the powder grains affect the
dispersion process. We used insoluble and non-cohesive grains to form islands of powders at a static water
surface. Liquid ?wicking? can avoid the formation of lumps, lead to complete sinking of powder grains when the
grain contact angle is below a critical value in the range 51°-77°. The effect of grain size on powder sinking, or
on the depth of island formed, was experimentally studied to understand the impact of particle size
enlargement on powder dispersion. The interplay of grain contact angle and size was also quantitatively
demonstrated. We also report the conditions leading to the detachment of a powder island from the interface,
forming a powder lump that is wet outside and dry inside. Importantly, introducing flow in the liquid by agitation
does not necessarily improve the dispersion process.