Numerical Study on Heat transfer and Pressure Drop Characteristic in Double Pipe Heat Exchanger

Double-pipe heat exchanger (DPHE) is one of the type of heat exchangers which usually used for low capacity application. This heat exchanger generally consist of two concentric pipe with plain or finned inner pipe. One fluid flow through the inner pipe, and the other fluid flow through the annulus pipe in counter flow condition to get highest performance for given surface area. This heat exchanger is widely used because it's simple, economically, easy construction, cheaper, greater flow capacity, easier maintenance, and better thermal performance than the others. Double-pipe heat exchanger performance is determined based on heat transfer coefficient, pressure drop and effectiveness. Heat transfer efficiency and pressure drop are defined in terms of the Nusselt (Nu) number and the friction factor (f), respectively. The purpose of this study is to analyze the performance of multiple pipe heat exchangers by varying the Reynolds number as follows 2500, 3500, 4500, 5500, and 6500 using Ansys Fluent software. Based this research, it is found that the increase Nre (reynold number), Nu (nusselt number) and e (effectiveness) are also increasing, and f (friction factor) is decreasing. The Nusselt number is increased 2.13 times from 22.68 to 48.33, the friction factor decreased 2.44 times from 0.083 to 0.034, and the effectiveness increased 1.36 times from 0.225 to 0.306.