Researching a doctoral thesis at the College of Engineering at the University of Basrah to improve turbulent flow and heat transfer in a tube using different types of twisted tapes by Mohsen Habib Fajr.

In this study, the effect of introducing new forms of twisted tapes into a tube on the thermal and hydrodynamic fields was selected practically and numerically. The new forms presented included two types of tapering tapes, increasing and decreasing. As well as two types of twisted tapes with an increasing and decreasing tapering center. In addition to new types of twin twisted tapes, a constant heat flux was applied to the wall of the tube and the fluid used in the research, air, was running turbulently in the Reynolds range of 10,000 to 40,000. The complex nature of flow and heat transfer is described by the continuity and momentum equations as well as the energy equation. Twisted tapes were also designed and manufactured from aluminum, design and assembly of the test system. The thesis concluded that the use of these twisted tapes led to an increase in the number of Nusselt as well as in the coefficient of friction when compared with its counterparts of the empty tube. It also gave all cases of twisted tapes with a central tapering cut, as well as many Double and tapered twisted tapes have a higher thermal performance coefficient than that obtained in the case of traditional twisted tape. Three twist rates for these tapes are 3,4,5 were tested in this study, where the results showed an increase in Nusselt number, friction coefficient and thermal performance coefficient when decreasing the value of Twisting the results also showed an increase in the Nusselt number and a decrease in each ratio of the number of Nuts and the coefficient of friction and the ratio of the coefficient of friction in addition to the coefficient of thermal performance when increasing the Reynolds number