Published Paper Details:

Working towards the goal of saving energies and to make compact design for mechanical , chemical devices and plants. The enhancement of heat transfer is one of the key factors in design of heat exchangers. In this process without application of external power can enhance the heat transfer rate by modifying the design by providing the helical tubes, extended surface or swirl flow devices. Helical tube heat exchanger provides certain advantage such as compact structure, larger heat transfer surface area and improved heat transfer capability. This thesis shows the deviation of Nusselt Number and friction factor for different curvature ratio(????/???? ratio) and Reynolds Number. CFD analysis has been done for varying inlet conditions keeping the heat flux of the outer wall constant. The turbulent flow model with counter flow heat exchanger is considered for analysis purpose. Copper was used as the base metal for both inner and outer pipe. Water and nano fluid(Al2O3-H2O) was taken as the working fluid for both inner and outer tube. The results show that Nusselt Number and friction factor depend on curvature ratio. From the results complicated behavior of fluid flow is captured for both the fluids flowing inside the tube. With increase in D/d ratio (inverse of curvature ratio) the Darcy friction factor decreases with increase in Reynolds number. The value of Nusselt number was found to increase with increase in mass flow rate.