3D numerical and experimental analysis for thermal–hydraulic characteristics of air flow inside a circular tube with different tube inserts

摘要: Abstract Numerical and experimental analyses were carried out to study thermal–hydraulic characteristics of air flow inside a circular tube with different inserts. Three kinds inserts, including longitudinal strip inserts (both without holes) twisted-tape three twisted angles (α = 15.3°, 24.4° 34.3°) have been investigated for inlet frontal velocity ranging from 3 18 m/s. simulation was performed by 3D turbulence analysis the heat transfer fluid flow. Conjugate convective in field conduction are considered also. The experiments conducted shell exchanger overall counterflow arrangement. working side cold air, while hot Dowtherm on side. To obtain test section data, e-NTU (effectiveness-number unit) method is applied determine conductance (UA product) analysis. It found that coefficient pressure drop tubes (without hole) 7–16% 100–170% greater than those plain When holes used, 13–28% 140–220%, respectively, higher tubes. 13–61% 150–370%, Furthermore, it reduction ratio area approximately 18–28% may be obtained if used.