ارائه یک شیوه جایگزین برای طراحی کانالهای انتقال هوا از طریق برنامه نویسی در نرم افزار EES
محورهای موضوعی : یافته های نوین کاربردی و محاسباتی در سیستم های مکانیکی
1 - گروه مکانیک، واحد مشهد، دانشگاه آزاد اسلامی، مشهد، ایران
کلید واژه: روش سطح پاسخ, فن, تعیین اندازه, نرم افزار EES, کانال هوا,
چکیده مقاله :
در طراحی کانالهای هوا ابتدا یک سرعت مجاز برای هوا در شاخه اصلی در نظر می گیرند. سپس، بر اساس این سرعت و دبی در شاخه اصلی، قطر کانال و اتلاف هد در آن تعیین می شود. البته، برای کانالهای مستطیلی، ابعاد را با توجه محدودیت ارتفاع کانال مشخص می کنند. سپس، قطر کانال (یا ابعاد کانال مستطیلی) در شاخه های دیگر بر پایه دبی در هر شاخه و مقدار اتلاف هد شاخه اصلی به دست می آید. در پایان، هد فن بر پایه اتلاف هد در پراتلافترین شاخه تعیین می شود. بدیهی است که در صورت تغییر در شرایط، همه محاسبات باید تکرار شود. برای رفع این مشکل، در مقاله حاضر یک شیوه جایگزین از طریق برنامه نویسی در نرم افزار EES پیشنهاد می شود. در این روش، کافیست یک بار، شاخه ها به نرم افزار معرفی شوند. در ادامه، با تغییر شرایط، تنها لازم است برنامه دوباره اجرا شود. به منظور نمایش برتری این روش، از آن برای طراحی یک کانال نمونه استفاده می شود. در ادامه، یک تحلیل پارامتری برای تحلیل اثر ارتفاع کانال و سرعت در شاخه اصلی بر سطح ورق مصرفی انجام می شود. این تحلیل با استفاده از روش سطح پاسخ صورت می گیرد.
In the design of air ductworks, a permissible velocity for air in the main branch is taken firstly. Then, according to this velocity and flow rate in the main branch, the diameter of the duct and the corresponding head loss are computed. Here, for the rectangular ducts, the dimensions are found taking into account the limitations in the height of the duct. Thereafter, the diameter of the duct (or the dimensions of the rectangular duct) are calculated in other branches according to the flow rate in each branch as well as the head loss in the main branch. Finally, the fan head is obtained based on the head loss in the branches having the highest losses. It is obvious that change in the conditions in accompanied with the repetition of the computations. To remove this shortcoming, in this work, an alternative method is proposed through coding in the EES software. In this method, the branches are input to the code once. Then, with any changes in the conditions, the code is required to be run once more. To demonstrate the suitability of this method, it is utilized here for the design of a typical ductwork. Thereafter, a parametric analysis is undertaken to examine the effects of the duct height as well as the velocity on the main branch on the area of the consumed plate. This analysis is based on the response surface method.
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