The heat that is conducted through a body must frequently be removed (or delivered) by some convection process. For example, the heat lost by conduction through a furnace wall must be dissipated to the surroundings through convection. In heat-exchanger applications a finned-tube arrangement might be used to remove heat from a hot liquid. The heat transfer from the liquid to the finned tube is by convection. The heat is conducted through the material and finally dissipated to the surroundings by
convection. Obviously, an analysis of combined conduction-convection systems is very important from a practical standpoint.
Fin equation:
Consider the one-dimensional fin exposed to a surrounding fluid at a temperature T? as shown in figure . The temperature of the base of the fin is Tb. We approach the problem by making an energy balance on an element of the fin of thickness dx as shown in the figure. The defining equation for the convection heat-transfer coefficient is recalled as where the area in this equation is the surface area for convection. Let the cross-sectional area of the fin be (Ac) and the perimeter be (P). Then the energy quantities are Energy in left face = ,
Can be applied to three types of fins, depending on physical situation
CASE 1 The fin is very long, and the temperature at the end of the fin is essentially that of the surrounding fluid.
CASE 2 The end of the fin is insulated
CASE 3 The fin is of finite length and loses heat by convection from its end.
For case1 :- The boundary conditions are
المادة المعروضة اعلاه هي مدخل الى المحاضرة المرفوعة بواسطة استاذ(ة) المادة . وقد تبدو لك غير متكاملة . حيث يضع استاذ المادة في بعض الاحيان فقط الجزء الاول من المحاضرة من اجل الاطلاع على ما ستقوم بتحميله لاحقا . في نظام التعليم الالكتروني نوفر هذه الخدمة لكي نبقيك على اطلاع حول محتوى الملف الذي ستقوم بتحميله .
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