نوع مقاله : مقالة تحقیقی (پژوهشی)
نویسندگان
پژوهشگاه هوافضا، وزارت علوم، تحقیقات و فناوری، تهران، ایران
چکیده
هدف از این تحقیق تخمین مشخصات حرارتی یک منبع گرمایی با استفاده از روش حرارتی معکوس است. از تست تجربی و روش عددی برای تخمین ضریب انتقال حرارت جابه‌جایی و دمای منبع استفاده شده است. از یک روش مناسب عددی به نام روش گرادیان مزدوج در این تحلیل استفاده شده است. تغییرات زمانی دما با استفاده از یک سنسور در نقطه‌ای مشخص از یک میله فلزی ثبت شده و به عنوان ورودی در حل عددی مورد استفاده قرار گرفته است. دمای منبع حرارتی و ضریب انتقال حرارت جابه‌جایی جریان خروجی منبع بر حسب فاصله از میله، تخمین زده شده است. دو نسبت فاصله بدون بعد 2 و 6 مد نظر بوده و دلیل انتخاب این دو مقدار، بیرون و داخل بودن میله در ناحیه پتانسیل مرکزی جت بوده است. شناسایی مشخصات منبع گرمایی با استفاده از حرارت معکوس می‌تواند در تخمین خواص اجسامی که به ویژه در سپرهای حرارتی مورد استفاده‌اند کاربری مفید داشته باشد.
کلیدواژه‌ها
عنوان مقاله [English]
Hot Air Gun Identification by Inverse Heat Transfer
نویسندگان [English]
- Amir Mahdi Tahsini
- Samaneh Tadayon Mousavi
Aerospace Research Institute; Ministry of Science, Research and Technology.Tehran.IRAN
چکیده [English]
The aim of this paper is to identify the unknown properties of an industrial hot air gun using inverse heat transfer approach. A combination of experiments and numerical analyses is used to define the convection coefficient and the produced temperature of this device. A numerical solver is developed by employment of a straightforward and powerful inverse heat transfer method: “The conjugate gradient method for parameter estimation”. The variation of temperature versus time in a fixed point of a steel-304 rod is sensed by a thermocouple and is given as an input to the numerical solver. The produced temperature of the hot air gun and the variation of convection heat transfer coefficient of this device as a function of distance between gun and rod are estimated in this research. Two non-dimensional distances between hot air gun and head of rod, H/D, are considered in this research: 2 and 6. These distances are chosen based on the hot jet potential core, the former is inside the potential core and the latter is outside it. The identifications of this gun are used in the process of determining unknown thermal properties of insulating and ablative materials, which are essential components of ablative heat shields, by inverse heat transfer methods.
کلیدواژه‌ها [English]
- Inverse Heat Transfer
- Conjugate Gradient Method
- Forced Convection
- thermal properties
- Numerical analysis
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