Journal of Research in Mechanical Engineering and Applied Mechanics ISSN: 3107-4510 (Online)

Authors:-Mohammed Mostafizur Rahman, Md. Shamim Ahmed, Mohammad Zoynal Abedin

Abstract:-In order to develop highly efficient, low cost, lightweight, and small heat exchangers, the analysis of heat transfer enhancement has always been an interesting topic in the scientific community. In terms of thermal performance characteristics, this paper reviews the investigation of heat transfer enhancement by coiled tubes. It is founded that the heat transfer rates on the external side of a coiled tube are higher than the internal side of a coiled tube and the addition of few amounts of nanoparticles (Al2O3) significantly increases the heat transfer performance up to 1%. The study also summarizes that the best heat transfer characteristics of nanofluid were achieved when it flows through a coiled tube rather than a straight tube and Al2O3 nanofluid provides better performance in the heat transfer enhancement than that of CuO nanofluid in coiled tubes. It is also found that the turbulent heat transfer coefficient in the air could be achieved as much as two times higher and the effectiveness could be achieved as much as two times higher when compared with a straight tube for Reynolds number ranging from 20000 to 45000. In addition, the heat transfer coefficient in the air could be achieved as much as two times higher and the effectiveness could be achieved as much as 1.25 times higher when compared with a straight tube for low Reynolds number ranging from 6000 to 22000.