Newsletter  2022.11  Index

Theme : "20th The Dream of Flow Contest” Preface Byungjin AN, and Masaaki MOTOZAWA Report on the 20th Dreams of Flow Contest Motohiko NOHMI (Ebara Corporation) Investigation into efficient ventilating methods Yoichiro TAMADA, Shota YOSHIDA, Naoya OHBA, and Kohei KUYAMA (Waseda University) Amazing Liquid Metal Crown Ryuto ONOZUKA, Ryunosuke NISHIO, Kenshi OHNO, Ken HAYASHIDA, Ryuhei MUTO, and Toranosuke HORIKAWA (Tokyo Institute of Technology) The Dream of Flow Contest Retrospective Shunya UDA, and Yoshiharu KANETA (Nihon University) Demonstration of Portable electrical tomography system and its application  So SEGAWA (Chiba University)

 

Amazing Liquid Metal Crown

Ryuto ONOZUKA, Ryunosuke NISHIO, Kenshi OHNO, Ken HAYASHIDA, Ryuhei MUTO,
and Toranosuke HORIKAWA (Tokyo Institute of Technology)

Ryuhei MUTO, Ryuto ONOZUKA, Ryunosuke NISHIO and Toranosuke HORIKAWA

Abstract

The theme of the 20^th dream of flow contest was "The flow technology realizing a safe, peaceful and secure society”. Our team “Liquid Metal Crowns” challenged to observe a milk crown phenomenon with liquid metal fluid. The milk crown phenomenon is generally observed when a liquid droplet impacts onto a liquid surface. Our team challenged to express the theme of the contest through the technology with liquid metal fluid which is one of the candidate coolants of next-generation nuclear power plants. Crown represents the development and prosperity of a human society. Liquid metal gallium which is a low-melting-point metal was used in our experiment to form the liquid metal crown. The droplets of liquid Ga were produced and dropped onto the surface of liquid Ga pool as shown in Fig. 1. The distance between the liquid Ga droplet and the liquid Ga surface was 80 cm. The depth of liquid Ga pool was 4 mm. The dynamic behavior of crown formation was then observed with a high-speed camera. For comparison, experiments were also performed using colored water. The number of fingers formed on the top of the liquid metal crown was different from that of the colored water crown. The shape of the liquid metal crown was also different from that of water crown as shown in Movie. 1. The number of fingers observed in the experiment was theoretically analyzed. The number of fingers observed in the colored water experiments was almost the same with that of theoretical estimation. The number of fingers observed in the liquid metal experiments was much smaller than that of theoretical estimation. The number of fingers decreased possibly due to the coalescence of small fingers in the liquid metal experiments. Liquid metal Ga has a higher surface tension than colored water. The conical shape of the liquid metal crown might be formed due to large surface tension of liquid metal.

Key words

Liquid metal, Milk crown, Gallium, Flow.

Figures

Fig. 1  Experimental apparatus

(a) Liquid metal	(b)  Colored water
Movie. 1  Formation of the crown