摘要
为了减少传热过程中的热阻,实现节能降耗,强化换热是行之有效的措施。采用异型管和肋片相结合的方式以达到强化换热的目的。通过将扭曲管和不连续斜肋相结合,建立了不同肋排数的扭曲内肋管的几何和数学模型;在给定条件下,对模型进行了验证,并进行热力性能的三维数值模拟。结果表明:在相同雷诺数Re下,加肋扭曲管的努赛尔数大于不加肋扭曲管的努赛尔数,且加肋排数越多,努赛尔数Nu越大。相同条件下,带肋的扭曲换热管的阻力系数大于无肋的换热管,加肋排数越多,阻力系数越大。带肋扭曲管的j因子要比没有加肋扭曲管大,但随着流体流速的增加,压损增加,换热性能有所下降;八排肋扭曲管的强化换热因子(j)比不加肋扭曲管提高约9%。由场协同数判定:加肋扭曲管的场协同数优于不加肋扭曲管。因此,所研究的扭曲内肋管性能更优越。
Enhancing heat transfer is an effective method to reduce the heat transfer resistance and achieve energy saving in the flow process.The paper combines shaped tubes and fins to achieve the aims of enhancing heat transfer.To this end,the geometric and mathematical models of twisted inner fin tube with different number of tubes are established by the combination of the twisted tube and the discontinuous oblique fin.Under given conditions,the model is verified and the three-dimensional numerical simulation is carried out.The results show that the Nusselt number of the finned twisted tube is larger than that of the non-finned twisted tube at the same Reynolds number,and the more finned rows are,the larger the Nusselt number is.The resistance coefficient of the twisted tube is larger than that of the finless heat exchange tube at the same conditions,and the more finned rows are,the larger the resistance coefficient is.The heat transfer enhancement factor(j)of the finned twisted tube is larger than that of the twisted tube without the fin.However,the pressure loss increases and the heat transfer performance decreases as the fluid flow rate increases.The heat transfer enhancement factor(j)of the eight rows of finned twisted tubes is about 9%higher than that without fins.To the extent,the number of field synergies of the finned twisted tubes is superior to that of the un-finned twisted tubes.Therefore,the performance of the twisted inner fin tube is superior.
作者
李慧君
闫琪
LI Huijun;YAN Qi(School of Energy Power and Mechanical Engineering,North China Electric Power University,Baoding 071003,China)
出处
《电力科学与工程》
2019年第12期61-67,共7页
Electric Power Science and Engineering
关键词
扭曲内肋管
斜肋
换热性能
流阻性能
数值模拟
twisted inner fin tube
inclined fin
heat transfer performance
flow resistance performance
numerical simulation
