Heat transfer with laminar flow has wider applications in various field of engineering such as chemical industries, desalination plants, solar energy collectors etc. Improvement to increase the heat transfer rate in existing heat exchangers becomes essential with increase in operational time of heat exchanger because of factors like fouling and scaling. Various techniques have been described in literature to enhance heat transfer rate in heat exchangers. However, most of the studies are restricted to plain tubes of small hydraulic diameter. In most of the past studies the friction factor was correlated to Reynolds number. Science in a large hydraulic diameter pipe hydrostatic pressure is one of the major parameter in addition to Reynolds number the prediction of friction factor using correlations based on Reynolds number only may deviate from reality for large hydraulic diameter pipe. In some applications, such as air liquefaction process, crude oil transport over large distance involves large diameter pipes demanding large amount of pumping power. Determination of accurate friction factor is essential for such devices. Hence there is a need for studying friction factor for large hydraulic diameter systems. In the present work a flow visualisation study has been conducted in a newly built Reynolds apparatus to know the flow pattern with twisted tape and wire coil insert. An analysis has been done to correlate the friction factor as a function of Reynolds number and hydrostatic pressure. Experimental setup has been fabricated and a series of experiments conducted to know the friction factor and Nusselt number variation with Reynolds number in a large diameter duct with and without twisted tape insert. Correlation developed for friction factor as a function of Reynolds number Re, and new number Jaga, Ja for flow in a smooth pipe and an annulus. The present results can be applicable for a large hydraulic diameter setup. The thesis is organised as below. 1. Certificate 2. Dedication 3. Acknowledgements 4. Abstract 5. Content 6. Introduction 7. Literature Review 8. Experimental Setup 9. Flow Visualization 10. Results and Discussion 11. Conclussion and Future Scope 12. References 13. Appendix --------------------------------- 1. Download the full thesis as a PDF file 2. Also publications from this thesis and related topics by P. Suresh Kumar are offered for download