管程扰流传热与阻力实验中的特征长度  

Characteristic length in the experiment of heat transfer and friction for tube side disturbed flow

作　　者：李锋祥[1] 阎华[1] 丁玉梅[1] 杨卫民[1] 谭晶[1] 

机构地区：[1]北京化工大学机电工程学院,北京100029

出　　处：《计算机与应用化学》2008年第7期867-871,共5页Computers and Applied Chemistry

摘　　要：以管程扰流雷诺数、努塞尔数和达尔西阻力因数中的特征长度为切入点,结合各特征数的物理意义提出管程扰流特征长度选取准则。指出管程扰流有动态扰流和静态扰流之分,应选取不同的特征长度。进而结合管程转子组合式强化传热与自清洁装置"洁能芯"的传热和阻力实验,将不同特征长度条件下的实验数据处理结果进行比较讨论,验证管程扰流特征长度选取准则,同时也阐述转子组合式强化传热装置"洁能芯"的强化传热与阻力特性。实验表明,当21 000≤Re≤56 000,与光滑圆管相比,"洁能芯"使得管程努塞尔数提高15%～20%,总传热系数提高约20%,达尔西阻力因数约为光管的3倍～5倍。实验中特征速度和定性温度分别为管程平均流速和平均温度。所提出的管程扰流特征长度选取准则对于内插件管程扰流强化传热技术具有普遍的参考价值。Considering physical significance of Reynolds number, Nusselt number and friction factor, characteristic lengths in these characteristic numbers were first investigated to put forward a characteristic length selection rule for tube side disturbed flow. Tube side disturbed flow includes dynamic disturbed flow and static one, which refer to different characteristic length. Heat transfer and friction experiment of ＂JNX＂ was launched in consequence and data processing results according to different characteristic length were compared and discussed to prove the characteristic length selection rule. Meanwhile, heat transfer enhancement and friction properties of ＂JNX＂ were illustrated in detail. In the condition of 21 000≤ Re ≤ 56 000, ＂JNX＂ improved tube side Nusselt number by （15 - 20 ）% , overall heat transfer coefficient by 20% , friction factor by （3 -5 ） times relative with the same smooth tube. Characteristic velocity and qualitative temperature were defined to be the average flow velocity and average fluid temperature of the tube side. The characteristic length selection rule advanced here can be referred to by many inserts techniques.

关 键 词：管程扰流 特征长度 特征数 强化传热 阻力 

分 类 号：TK124[动力工程及工程热物理—工程热物理]