3种平直翅片的散热能力分析与比较

Analysis and comparison of heat dissipation capacity of three straight fins

从一维导热模型出发,推导建立了横截面分别为矩形、三角形、抛物线形的平直翅片的散热速率表达式,研究了它们在不同应用条件下各自的散热能力。研究表明:在充分利用给定单位空间(长方体或正方体)的情况下,矩形翅片具有最大的散热速率,三角形翅片、抛物线形翅片次之,抛物线翅片具有最大的单位体积(基于材料消耗)散热速率,其余二者次之。在给定材料消耗、给定翅片基底厚度与翅片宽度的情况下,随着外部换热系数的逐渐提高,3种翅片散热速率的相对大小会发生变化,逐渐从"抛物线形>三角形>矩形"变化到"矩形>三角形>抛物线形",翅片高厚比的大小决定了抛物线翅片在某个较小或较大的传热系数h值范围内保持相对于其余2种翅片的固有散热优势,而这种优势最终会被矩形翅片所代替。

Proceed from one-dimension-heat-conduction model, the cooling rate equations of the fins were deduced with their cross sections in shape of rectangular, triangular, parabolic. With the different application background, the cooling capacity of these fins was calculated and studied. The investigation shows that in full use of a given unit space （cuboids）, rectangular fin has the highest cooling rate, followed by the triangular and parabolic fins. Parabolic fin has the biggest unit volume cooling rate （based on the materials consumption ） , the triangular and rectangular come second. In a given material consumption, fin based thickness and width, along with the increasing external heat transfer coefficient, the relativity of their cooling rates may change, and gradually from ＂parabolic 〉 triangular 〉 rectangular＂ changes to ＂ rectangular 〉 triangular 〉 parabolic＂ , the ratio of height to thickness determines whether the parabolic fin in a smaller or larger range of the coefficient of heat transfer keeps the relative preponderant to the rest of the two fins because of its inherent advantages, and this advantage can eventually be rep.laeed by the rectangular fin.