正反扭转扭带层流换热及摩擦特性的实验研究  

Experimental Study on Laminar Flow Heat Transfer and Friction Characteristics in Circular Tubes with Left-right Twisted Tapes

作　　者：满长忠[1] 姚金钰 吕晓刚[1] 孙培岩[1] 

机构地区：[1]大连理工大学海洋能源利用与节能教育部重点实验室,辽宁大连116024

出　　处：《热能动力工程》2017年第1期18-24,共7页Journal of Engineering for Thermal Energy and Power

摘　　要：本文提出将一种正反扭转且带有双排半圆切口的新型扭带用在套管式换热器上在层流条件下对换热器其换热性能和流动特性进行实验研究并分析这种扭带的综合性能。实验工质为水,Re(雷诺数)变化范围为540~1 440。本实验采用4种不同长度扭带做对比,4种分别是全长、3/4长、半长和1/4长扭带。结果显示,插入全长、3/4长、半长和1/4长扭带的换热Nu(努塞尔数)分别是光管的1.92~3.80,1.69~3.20,1.60~2.62和1.48~2.23倍;f(摩擦阻力系数)分别是光管的3.69~6.30,3.30~5.51,2.72~4.67,2.33~3.55倍;对应的PEC(综合性能指标)分别为1.24~2.06,1.14~1.81,1.15~1.57和1.11~1.47。插入全长扭带在实验范围内达到了最优,插入其它长度扭带的PEC也都高于1,可以应用在压力较小的工况下。最后,本文还对该类型扭带拟合了实验关联式,通过对比实验值和预测值,Nu和f的误差均在10%以内,这为今后的研究提供了理论依据。This paper presents a left-right twisted tape with a double-row semicircular cut. Through experimental study of heat transfer and flow characteristics in a dual-pipe heat exchanger at laminar flow condition,the overall performance of this type of twisted tape was analyzed. With Working fluid water and Re range from 540- 1 440,four different lengths twisted tape were selected to do comparison; a full length,3 /4 length,half-length,and 1 /4 length,respectively. The results showed that the Nusselt numbers between the fluid and inner tube for these four cases are1. 92- 3. 80,1. 69- 3. 20,1. 60- 2. 62,and 1. 48- 2. 23 times as large as that of the plain tube. The frictionfactors( f) for each case are 3. 69- 6. 30,3. 30- 5. 51,2. 72- 4. 67,and 2. 33- 3. 55 times that of the plain tube. The corresponding performance evaluation criteria( PEC) are 1. 24- 2. 06,1. 14- 1. 81,1. 15- 1. 57,and1. 11- 1. 47,respectively. The full-length twisted tape achieves the optimal effect with the experimental range.However,the PEC for other types is also higher than 1,and they also have plenty of room for applications under low pressure conditions. Additionally,the correlation between Nusselt number and friction factor was also established in this paper. The comparison between the correlation prediction and experimental data indicated the error for Nusselt number and friction factor is within 10%.

关 键 词：正反扭转扭带 层流 强化换热 套管式换热器 

分 类 号：TK124[动力工程及工程热物理—工程热物理]