Flow Characteristics of Two-Dimensional Supersonic Under-Expanded Coanda-Reattached Jet

• 作者: Tetsuji Ohmura Toshihiko Shakouchi Shunsuke Fukushima Koichi Tsujimoto
• 来源期刊: 流量控制、测量及可视化(英文)
• 学科: 物理学
• 关键词: Supersonic Flow Under-Expanded Jet Coanda Reattached Jet Flow Visualization Gas-Atomization Experimental Analysis Numerical Analysis
• 年，卷（期）: 2021,（1）
• 页码范围: 1-14
• 页数: 14页
• 分类号: O35

摘要

<span><span style="font-family:;" "=""><span style="font-family:Verdana;"></span><span style="font-family:Verdana;">When there is a wall near the jet, it deflects and flows while being attached to the wall owing to the Coanda effect. The flow characteristics of the incompressible and two-imensional (2D) Coanda-reattached jets have been considerably explained. However, 2D supersonic under-expanded jets, reattached to side walls, have not been sufficiently investigated. These jets are used in gas-atomization to produce fine metal powder particles of several micrometers to several tens micrometers. In this case, the supersonic under-expanded jets are issued from an annular nozzle, which is set around a vertically in</span><span style="font-family:Verdana;">stalled circular nozzle for molten metal. The jet flow at the center</span><span style="font-family:Verdana;"> cross</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">-</span></span></span><span><span><span style="font-family:;" "=""><span style="font-family:Verdana;">section of the annular jet resembles a 2D Coanda-reattached jet that deflects and attaches on the central axis. In this study, the flow characteristics of a supersonic under-expanded Coanda air jet from a 2D nozzle that reattaches to an offset side wall are elucidated through experiment and numerical analysis. For numerical analysis, we show how much it can express experimental results. The effects of supply pressure </span><i><span style="font-family:Verdana;">P</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"></span></i>_{<span style="font-family:Verdana;">0</span><span style="font-family:Verdana;"></span>}</span><span style="font-family:Verdana;"></span><span style="font-family:Verdana;"> on the flow characteristics such as the flow pattern, size of shock cell, reattachment distance, and velocity and pressure distributions, etc. are examined. The flow pattern was visualiz