مطالعه‌ی آزمایشگاهی اثر چرخش جت سیال بر پرش‌های هیدرولیکی دایروی

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشگاه بیرجند

2 Shahid Avini

3 گروه مکانیک دانشگاه فردوسی مشهد

چکیده

هرگاه یک جت سیال متقارن محوری به صورت عمودی به یک صفحه‌ی هدف افقی برخورد کند، یک پرش هیدرولیکی شکل می‌گیرد. مطالعات زیادی در زمینه‌ی پرش‌های هیدرولیکی دایروی انجام شده‌است. اما تاکنون هیچ گاه اثر پارامتر مهم و کلیدی چرخش جت سیال در پرش‌های هیدرولیکی مورد توجه قرار نگرفته‌است. هدف اصلی در این تحقیق مطالعه‌ی اثر چرخش جت سیال بر پدیده‌ی پرش هیدرولیکی دایروی است. نتایج این تحقیق که به کمک روش آزمایشگاهی بدست‌آمده‌است، نشان می‌دهد هر چه قدر سرعت زاویه‌ای بیشتر شود، میزان افزایش شعاع پرش دایروی بیشتر می‌شود. ترسیم نمودار شعاع بی‌بعد پرش بر اساس عدد بی‌بعد چرخش نشان می‌دهد که دو دسته خطوط قابل شناسایی است. دسته‌ی اول خطوط سرعت زاویه‌ای ثابت با شیب منفی و دسته‌ی دوم خطوط دبی ثابت با شیب مثبت است. نتایج نشان داد که افزایش سرعت زاویه‌ای جت چرخشی نسبت به افزایش دبی سیال اثر کمتری بر افزایش شعاع پرش هیدرولیکی دایروی دارد. همچنین آزمایشات نشان می‌دهد که پرش‌های هیدرولیکی ایجادشده به وسیله‌ی یک جت چرخشی، با کمی اختلاف از روند نتایج تئوری اصلاح شده‌ی واتسون پیروی می‌کند.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Experimental Study of the Effect of Fluid Jet Swirl on Circular Hydraulic Jump

نویسندگان [English]

  • Ali Asadi 1
  • Seyyed Majid Malek Jafarian 2
  • Ali Reza Teymourtash 3
1 Department of Mechanical Engineering, University of Birjand, Birjand, Iran
2 Shahid Avini
3 Department of Mechanical Engineering, Ferdowsi University of Mashhad, Mashhad, Iran
چکیده [English]

When an axially symmetrical fluid jet impacts on a horizontal plate vertically, a hydraulic jump is formed. Numerous studies are conducted on circular hydraulic jumps. However, the effect of the important and key parameter of fluid jet swirl on hydraulic jumps is not investigated. The main purpose of this study is to investigate the effect of this parameter on the circular hydraulic jump. The results of this study, achieved by using experimental method, show that the higher the angular velocity, the higher the increase in the radius of the jump. Drawing the diagram of the dimensionless radius of jump based on the dimensionless number of swirl shows two categories of lines. The first category is the constant angular velocity lines with a negative slope and the second category is the constant flow rate lines with a positive slope. The results showed that increasing the angular velocity of the swirling jet has less effect on increasing jump radius than increasing the flow rate. Experiments also showed that the hydraulic jumps created by a swirling jet follow the trend results of modified Watson’s theory with a non-significant difference.

کلیدواژه‌ها [English]

  • Circular Hydraulic Jump
  • Swirl Jet
  • Angular Velocity of Nozzle
  • Modified Watson’s Theory
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