مطالعه تجربی جت مایع مستطیلی با ضریب منظری بالا در جریان گازی موازی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه صنعتی امیرکبیر، دانشکده مهندسی هوافضا

2 صنعتی امیرکبیر*مهندسی هوافضا

3 دانشگاه صنعتی امیرکبیر

چکیده

در این پژوهش، فیزیک جریان یک جت مستطیلی تزریق شده به درون جریان هوای موازی به صورت تجربی مورد مطالعه قرار گرفت. جریان جت مایع توسط یک انژکتور مستطیلی با ضخامت 0/64 میلیمتر و ضریب منظری 21 تولید شد. این انژکتور به صورت موازی و با استفاده از یک نگهدارنده خاص برای کاهش اثرات اغتشاشی در مرکز اتاقک آزمون تونل باد فروصوت قرار گرفت. به منظور شناسایی فیزیک جریان از روش سایه‌نگاری و برای ثبت تصاویر از عکسبرداری سرعت بالا استفاده شد. به منظور بررسی و تحلیل فیزیک جریان، آزمایش‌ها در بازه گسترده‌ای از شرایط جریان انجام شده و تصاویر آشکارسازی ارائه شده است. در این پژوهش عدد وبر جت و عدد وبر گاز به ترتیب بین 3 تا 120، و 0/2 تا 13 تغییر یافته‌اند. نشان داده شد که اثرات جریان گاز باعث ایجاد موج‌های متناوب کمانی شکل بر روی ستون جت مایع می‌شود که باعث تسریع شکست جت می‌شوند. همچنین، برای اولین بار رژیم‌های مختلف جریان شامل رژیم ستونی، ستونی/گرانشی، کمانی، کیسه و ترکیبی شناسایی و معرفی شدند. یک نقشه دسته‌بندی با متغیرهای عدد وبر گاز و نسبت مومنتوم نیز برای تفکیک این رژیم‌ها ارئه شد. طول شکست جریان مایع نیز اندازه‌گیری شد و نتایج آن بر حسب متغیرهای مختلف ارائه شد. نتایج نشان می‌دهد با افزایش عدد وبر جت سیال در سرعت ثابت جریان گازی، طول شکست افزایش می‌یابد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Investigation of a High Aspect Ratio Rectangular Liquid Jet in Parallel Airflow

نویسندگان [English]

  • Ashkan Alimehr 1
  • Mehran Tadjfar 2
  • Amin Jaberi 3
1 Department of Aerospace Engineering
2 Aerospace Engineering Department
3 Amirkabir University of Technology
چکیده [English]

In this study, the flow dynamics of a high aspect ratio rectangular liquid jet issued into parallel airflow was experimentally investigated using a proof of concept setup, a more appropriate setup will be designed for a complete study later. The liquid flow was emanated from a rectangular injector with a thickness of 0.64 mm and an aspect ratio of 21. The injector was set in the center of the test section and the effects of airflow on the liquid flow were evaluated. A particular holding mechanism was designed and built to minimize the induced perturbations on the liquid flow. To identify the physics of the liquid flow shadowgraphy technique and high-speed imaging were implemented. In order to provide a comprehensive study of the problem, the experiments were performed for a wide range of flow conditions, and flow visualizations were presented. Jet Weber number and Gas Weber number were varied from 3 to 120 and 0.2 to 12, respectively Also, five regimes of the liquid flow including column, column/gravity, arcade, bag, and multimode were recognized. A mapping with gas Weber number and momentum ratio as the determining variables was suggested to distinguish these regimes from each other. The breakup length of the liquid jet was also measured. It was found that with the increase of jet Weber number the breakup length was increased at constant gas speed. Moreover, it was revealed that the breakup length was elongated with the increase of gas Weber number.

کلیدواژه‌ها [English]

  • Parallel injection
  • rectangular liquid jet
  • liquid flow instability
  • Experimental study
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