The development of flow control method for the circular jet using surrounding sub nozzles

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K23500
• Research Category: Grant-in-Aid for Research Activity Start-up
• Allocation Type: Multi-year Fund
• Review Section: 0301:Mechanics of materials, production engineering, design engineering, fluid engineering, thermal engineering, mechanical dynamics, robotics, aerospace engineering, marine and maritime engineering, and related fields
• Research Institution: Ishikawa National College of Technology
• Principal Investigator: Teramoto Hiroshi 石川工業高等専門学校, 機械工学科, 助教 (70847376)
• Project Period (FY): 2019-08-30 – 2022-03-31
• Keywords: 噴流 / 複数円形ノズル / 流体計測 / 流体混合 / 噴流の干渉 / 熱線流速計

Outline of Final Research Achievements

The purpose of this study is to investigate the flow characteristics of multiple jets formed by a circular nozzle surrounded by multiple sub nozzles, and to propose a method to control mixing of the circular main jet by the sub jets.
When circular sub nozzles are used, the velocity ratio is 1. When the diameter ratio of the main and sub nozzles is 1/2, the main jet reached about 5 times the nozzle diameter.
The merging of the jets is caused by the spreading of the each circular jets, regardless of the number of sub nozzles, and mixing of the main jets can be accelerated by increasing the distance between the main nozzle and the circular sub nozzles to about three times the main nozzle diameter. A similar effect can be obtained with elliptic sub nozzles, where the distance between the main and sub nozzles is also about three times the diameter of the main nozzle.

Free Research Field

流体工学

Academic Significance and Societal Importance of the Research Achievements

本研究により得られた成果は複数噴流利用機器の性能向上や設計に資する知見と考える．
これまでに研究報告例が極めて少ない，円形主噴流に対する円形及び楕円形複数副噴流による受動的制御について実験的な手法によって種々の流動特性を明らかにし，円形主噴流の到達距離の短縮・混合の促進が可能な条件を見出した．
その他にも噴流の発達過程における速度分布の変化や混合の強さ，また噴流の変形の様子などについて明らかにした．