Modification for helical turbulator to augment heat transfer behavior of nanomaterial via numerical approach

• Published in: Applied thermal engineering Vol. 182; p. 115935
• Main Authors: Sheikholeslami, M., Jafaryar, M., Said, Zafar, Alsabery, Ammar I., Babazadeh, Houman, Shafee, Ahmad
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 05-01-2021; Elsevier BV
• Subjects: Computational fluid dynamics; Convection; Exergy; Fluid flow; Heat exchangers; Heat transfer; Helical flow; Helical tape; Irreversibility; Nanomaterials; Nanoparticle; Nusselt number; Pumping; Reynolds number; Secondary flow; Temperature; Velocity gradient; Irreversibility; Exergy; Nanoparticle; Helical tape; Convection
• ISSN: 1359-4311; 1873-5606
• DOI: 10.1016/j.applthermaleng.2020.115935

•Helical tapes were applied to intensify turbulence intensity in this paper.•Copper oxide was dispersed into water to improve thermal features.•Insertion of helical tape leads to thinner boundary layer.•Thermal irrevesibility reduces about 89.95% with augment of pumping power.•Lower surface temperature causes exergy drop to decline.
Energy demand makes a noteworthy concern in these days. In engineering fields, heat exchangers were utilized for cooling purpose and to improve the efficiency, tapes with various configurations can be installed. Utilizing multi helical tape (MHT) is main purpose of current context. In current turbulent simulation, transportation of nanomaterial within a tube has been scrutinized. To augment flow blockage, helical tape (HT) was employed with various width ratio (BR). Multiple tapes make the flow more disturber and increase the resistance. Widths of MHT and inlet velocity were supposed as main variables and outputs were illustrated in view of contours and bar charts. Due to increase of velocity gradient, Sgen,f (frictional entropy) increases by about 58.9% with augment of width of tapes. The increased Sgen,f with augment of Reynolds number (Re) is attributed to greater secondary flow with augment of pumping power. Reduction of temperature of wall with rise of width of tapes results in higher Nusselt number. Moreover, Nusselt number (Nu) for maximum inlet velocity is around 2.3 times greater than that of minimum inlet velocity. Sgen,th (thermal irreversibility) reduces about 89.95% with augment of pumping power at BR = 0.098. Lower surface temperature causes exergy drop to decline as a result of augmenting in Re.