Amirkabir University of Technology Amirkabir Journal of Mechanical Engineering 2008-6032 53 5 2021 07 23 Numerical simulation of heat transfer and pressure drop of pseudo-plastic fluid in a pipe heat exchanger equipped with a modified twisted tape Numerical simulation of heat transfer and pressure drop of pseudo-plastic fluid in a pipe heat exchanger equipped with a modified twisted tape 3077 3098 3880 10.22060/mej.2020.3880 FA Bahador Fathipour Department of Mechanical Engineering, Arvandan Nonprofit Higher Education Institute, khoramshahr, Iran 0000-0001-6457-5688 Ashkan Ghafouri Departmant of Mechanical Engineering, Islamic Azad University Ahvaz branch, Ahvaz, Iran 0000-0002-2259-9080 Kazem Mohammadzadeh department of energy engineering, quchan univercity of tecnology, quchan, iran, P.O. box 947771-67335 0000-0002-7421-6774 Journal Article 2019 12 17 The present paper, heat transfer and flow of shear-thinning non-Newtonian fluids in a circular tube under constant heat flux with a modified twisted tape, have been numerically studied in a laminar, steady-state and three-dimensional regime. The finite volume method was used to numerically solve the governing equations, modified power-law model be used to describe the dependence between the stresses and shear rates. The physical model is a circular tube with a standard twisted tape with decreasing its width, also a hollow tape in circular tube with an increase in the central cavity of the tape. The heat transfer and the overall performance are unfavorable by cutting off the tape edge. Instead, a decrease in tape width ratio, hollow tape with different removal ratios was used to improve thermal efficiency. the numerical results show that the removal ratio (hollow width of the tape divided by the initial width) equal to 0.3 in the fluids with behavioral indexes 0.86, 0.55 and 0.41 can cause 17.95%, 18.49% and 19.69% increase in thermal performance compared to the best thermal performance mode, respectively. Therefore, the hollow twisted tape is a promising technique for laminar convective heat transfer enhancement. The present paper, heat transfer and flow of shear-thinning non-Newtonian fluids in a circular tube under constant heat flux with a modified twisted tape, have been numerically studied in a laminar, steady-state and three-dimensional regime. The finite volume method was used to numerically solve the governing equations, modified power-law model be used to describe the dependence between the stresses and shear rates. The physical model is a circular tube with a standard twisted tape with decreasing its width, also a hollow tape in circular tube with an increase in the central cavity of the tape. The heat transfer and the overall performance are unfavorable by cutting off the tape edge. Instead, a decrease in tape width ratio, hollow tape with different removal ratios was used to improve thermal efficiency. the numerical results show that the removal ratio (hollow width of the tape divided by the initial width) equal to 0.3 in the fluids with behavioral indexes 0.86, 0.55 and 0.41 can cause 17.95%, 18.49% and 19.69% increase in thermal performance compared to the best thermal performance mode, respectively. Therefore, the hollow twisted tape is a promising technique for laminar convective heat transfer enhancement. https://mej.aut.ac.ir/article_3880_0dd1bc593a91620daecf7723d2235624.pdf