四类螺旋翅片管束热力特性数值研究

对气流横掠螺旋翅片管错列管束的流动与换热特性进行了数值研究,在雷诺数Re=10 000～40 000范围比较了四类(连续型、平齿I型、平齿L型和扭齿型)螺旋翅片管束的换热、阻力及热力综合性能。结果表明:与常规的连续型管束相比,在相同Re下,平齿I型、平齿L型和扭齿型管束的努塞尔数Nu分别提高约24%、32%和38%,欧拉数Eu分别增大约24%、85%和90%;在相同的换热量、流体输运功耗和翅片管结构参数下,平齿I型、平齿L型和扭齿型管束所需的换热面积较之连续型管束所需的分别减小约9%、6%和12%,扭齿型表现最佳;在管束紧凑性方面,连续型、平齿I型和扭齿型管束无明显差别,但选用平齿L型会使管束体积相对增大约18%。

Numerical study on thermal-hydraulic characteristics of four types of helical finned tube banks

A numerical study on the flow and heat transfer characteristics of helical finned tube bank with staggered layouts was performed. The comparison of heat transfer, pressure drop and overall thermal-hydraulic performance among four types of fin structures such as solid-fin, I-foot serrated-fin, L-foot serrated-fin and twisted-fin was conducted in Reynolds number Re range of 10 000~40 000. The results showed that comparing with the solid-fin tube bank under the same Re, Nusselt numbers of I-foot serrated-fin, L-foot serrated-fin and twisted-fin tube banks increased by approximately 24%, 32% and 38%, respectively. Meanwhile, their Euler numbers augmented by approximately 24%, 85% and 90%, respectively. Under the same heat duty, power consumption for fluid transportation, and structure parameters of finned tube banks, the heat transfer areas of I-foot serrated-fin, L-foot serrated-fin and twisted-fin tube banks decreased by approximately 9%, 6% and 12%, respectively, meaning that the twisted-fin tube bank had the best performance of saving heat transfer area. Regarding the compactness of tube banks, there was no difference among the solid-fin, I-foot serrated-fin and twisted-fin tube banks, while the spatial volume of the L-foot serrated-fin tube bank enlarged by 18% in comparison with the other tube banks.