Enhancement of heat transfer in thermal systems by modification in geometry and fluid properties

Abstract

The current industry needs high-performance thermal systems with newlinehigher heat transfer rates. A heat exchanger is one of the major subsystems in newlinepower plants and various process industries. Such a system needs to be newlinecompact and losses minimized. In the heat transfer process, the heat transfer newlinecoefficient is considered to be the derived property that depends on geometric, newlineflow and fluid properties. Hence the research is devoted to enhance the newlinethermal performance of heat exchangers by modification of geometry and newlineheat transfer fluids. Modification of geometry with the use of alternative newlineturbulator inserts would pave the way for better performance. Moreover, newlinewhen alternative nanofluids are tried, there is a scope for finding a better newlinesolution. newlineAs a modification of geometry, an evolved design of a serrated newlinetwisted tape turbulator based on an owl s serrated wings is performed and newlineexperimented with. The effectiveness of heat exchangers without and with newlineturbulator is 0.41 and 0.47 respectively. Hence, the Thermal Enhancement newlineFactor (TEF) achieved due to the turbulator is 1.15. newlineFew nanoparticles have been synthesized and then characterized. newlineThe FESEM results provide the particle sizes to be 15, 20 and 25 nm for Ag, newlineSiO2 and CaCO3 respectively. The nanofluids have been prepared with varying newlinevolumetric percentages of the nanoparticles and adding very small quantities of newlineCaCO3 nanoparticles as stabilizers. 0.02 volumetric percentage of SiO2 + 0.004 newlinevolumetric percentage of CaCO3 nanofluid has got a zeta potential of newline-36.1 mV which is close to that of silver newline