مدلسازی سه بعدی جریان حول کلکتور برای تعیین ضرایب آیرودینامیکی و بار دینامیک سازه

نوع مقاله: مقاله مکانیک

نویسندگان

1 دانشگاه تفرش

2 دانشکده مهندسی مکانیک، دانشگاه تفرش - تفرش

چکیده

در میان روش های تولید برق به کمک انرژی خورشیدی، مزرعه خورشیدی با آینه های سهموی شکل دارای هزینه رقابتی با نیروگاه های دیگر می باشد. یکی از اساسی ترین بخش های طراحی این نیروگاه ها، بخش سازه کلکتورهای سهموی می باشد. در این سازه ها نیروی باد مهمترین موضوع در بحث طراحی می باشد. در این مقاله نحوه تعیین نیروی باد و عوامل موثر بر میزان نیروی پسا تشریح شده است. برای محاسبه نیروی باد از روش دینامیک سیالات محاسباتی کمک گرفته شده است. در نهایت به کمک ضرایب آیرودینامیکی تحلیل تنش وارده بر کلکتور خورشیدی محاسبه شده و سازه کلکتور در برابر این باد بررسی می شود. برای مدلسازی از هندسه سه بعدی استفاده شده این موضوع باعث می شود که اثر لبه و شیارها دقیق تر مدل گردد و پروفیل فشار در کل آینه و ممان وارده بر سازه قابل محاسبه باشد. درنهایت محاسبات تنش انجام پذیرفته است. جریانهای مورد بررسی برای سرعت های 5 ، 10 و 20 متر بر ثانیه معادل رینولدز 1 الی 4 میلیون بوده است. نتایج سه بعدی نشان داده است که اثر گردابه های پشت کلکتور قابل توجه بوده و این گردابه ها باعث نوسان و ایجاد بار دینامیک قابل توجه می شود. گردابه ها باعث نوسان در ضریب پسا و برا در حدود 16.4% می شود و عدم مد نظر قرار دادن این موضوع باعث می شود که بار دینامیک محاسبه نشده و تنش بیشینه در حدود 35.3% کمتر محاسبه گردد.

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Three-Dimensional Simulation of Air Flow around Collectors to Obtain Aerodynamic Coefficients and the Collectors Dynamic Loads

نویسنده [English]

  • zahra baniamerian 2
2 Department of Mechanical Engineering, Tafresh University, Tafresh, Iran
چکیده [English]

Fossil fuels are going to either be gone or they are going to become too expensive to realistically use. This issue along with the air pollution caused by these kinds of fuels provides specific concentrations for renewable energies. Most of the common methods for electricity generation by use of solar energy are not economic. However, among the methods, solar plants equipped with parabolic collectors are more acceptable. A parabolic trough collector (PTC) is a system in which reflective parts (like mirror or aluminum plates) are installed in parabolic form upon steel bases. Parallel arrays of such collectors are commonly installed subsequently in vast open fields to form a power plant, called solar farm. These power plants are usually subjected to high wind speeds without much shelter or protection. The aerodynamic loads due to wind blow should be reduced as far as possible. Designing the collector arrangement as well as collectors structures is of most important sections of establishing such power plants due to the wind force effects. In the present study, methods of calculating wind force and the effective parameters on the drag force are discussed. Wind force calculation is accomplished using CFD. Aerodynamic factors are calculated in the 3D model and in consequence shear analysis is performed for the collector and its structure. Simulating the problem in three-dimension provides the condition for more precise modeling of flow in between collectors distance, pressure distribution in collectors and the exerted moment on collectors structures.

کلیدواژه‌ها [English]

  • Twisted tape
  • Solar plant
  • Aerodynamic forces
  • Drag and Lift force
  • Structural design

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