Accurate characterization of bubble mixing uniformity in a circular region using computational geometric theory--颗粒学报PARTICUOLOGY

Sun, H., Xu, J., Wang, S., Cai, G., Wang, H., & Yin, W. (2024). Accurate characterization of bubble mixing uniformity in a circular region using computational geometric theory. Particuology, 86, 149-159. https://doi.org/10.1016/j.partic.2023.05.005

Accurate characterization of bubble mixing uniformity in a circular region using computational geometric theory

Hui Sun ^{a b c}, Jianxin Xu ^{a b *}, Shibo Wang ^{a b}, Guangcheng Cai ^c, Hua Wang ^{a b}, Wuliang Yin ^d

a State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, 650093, China
b Faulty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, China
c Faculty of Science, Kunming University of Science and Technology, Kunming, 650500, China
d Department of Elec. and Electronic Engineering, University of Manchester, Manchester, M13 9PL, UK

10.1016/j.partic.2023.05.005

Volume 86, March 2024, Pages 149-159

Received 21 March 2023, Revised 30 April 2023, Accepted 11 May 2023, Available online 29 May 2023, Version of Record 6 June 2023.

E-mail: kmustjianxinxu@163.com

Highlights

• The proposed method is based on computational geometric theory.

• The method can quantify the uniform distribution of bubble swarm Accurately.

• Effectiveness of the novel method is verified on both numerical and experimental.

• Evaluation indicator is established to evaluate the uniform distribution in circular region.

• The method can be used in engineering fields of uniformity evaluation in circular region.

Abstract

The present study proposes a novel method based on the geometric theory for measuring the distribution of bubble swarms in the circular region of a direct-contact heat exchanger. It was determined that the mixing is uniform when the average distance between the bubble swarms in the unit circular region is approximately 0.9054, which is the standard reference value. The effect of sample size (i.e., the number of bubbles) on mixing uniformity was investigated to determine the optimal sample size. It was verified that the metric's accuracy and stability were higher with a sample size of 155. Accordingly, it was proposed to increase the sample size by filling irregular bubbles using a segmentation method, which enabled a further accurate assessment of the mixing uniformity. The mixing uniformity of bubble swarms in the circular region and its maximum internal connection with the square region was accurately quantified. It was revealed that the relative average error increased by approximately 3.47% due to information loss. The proposed method was demonstrated to be rotationally invariant. The present study provided novel insights into evaluating mixing uniformity, which would guide enhanced heat transfer and the effective evaluation of the spatiotemporal characteristics of transient mixing in circular regions or the cross-sections of chemical transport pipelines.

Graphical abstract

Keywords

Direct-contact heat exchanger; Circular region; Bubble swarm; Distribution uniformity; AD-Circle method

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