Characteristics of an internal-mixing atomiser with supersonic configuration for metal powder production. (November 2015)

• Record Type: Journal Article
• Authors: Wang, M.-R.; Chen, P.-J.
• Is Part Of: Materials research innovations. Volume 19(2015)Supplement 8
• Page Start: S8-740
• Page End: S8-742
• Publication Date: 2015-11
• Subjects: Gas atomisation -- Internal-mixing atomiser -- Droplet size; Materials -- Research -- Periodicals; Matériaux -- Recherche -- Périodiques; 620.1105
• DOI: 10.1179/1432891715Z.0000000001880
• Languages: English
• ISSNs: 1432-8917

Abstract

Abstract : This paper describes the production of metal powder using an atomiser with internal-mixing mechanisms under supersonic configuration. The atomiser is designed with a convergent–divergent channel and a confinement section. The atomisation gas was first accelerated to supersonic speed through the annular convergent–divergent channel. It was then introduced to the confinement section and impinged onto the melt injected from the delivery tube. The interaction between the atomisation gas and the melt in the confinement section resulted in the atomisation of the melt. The confinement of the region downstream of the delivery tube is called the internal-mixing zone. Flow expansion was observed in the internal-mixing zone as the supersonic flow came out from the divergent section. The liquid phase was confined by the high-speed gas flow in the centre of the atomiser. The velocity of atomisation gas can further increase through the flow expansion and the high-velocity region of atomisation gas is extended. The results showed that the negative pressure at the outlet of the delivery tube decreased as the confinement length increased at different gas pressure owing to the enlargement of high-velocity region of atomisation gas. It is also found that the atomiser with a longer internal-mixing length can produce the same median droplet size at lower gas-to-liquid ratio and has higher atomisation efficiency. It can be concluded that the confined section of the atomiser can be used to enhance the atomisation process and to control the particle size.