Thermal performance investigation of double pipe heat exchanger embedded with extended surfaces using nanofluid technique as enhancement

Abstract

In the present work, a numerical investigation of heat transfer enhancement in a “double pipe heat exchanger” embedded with an extended surface on the inner tube's outer surface with the addition of “Alumina nanofluid” has been carried out. Through the annuli, water with varying mass flow rates (0.03–0.07 kg/s) and hot de-ionized water with varying Reynolds numbers (250–2500) flows, while hot de-ionized water flows through the inner tube. One type of nanoparticle (Al2O3) having volume concentrations (1%, 3%, and 5%) was used during simulation. Numerical analysis was performed using Computational Fluid dynamics, and the Solid works was used to generate the model. A Semi-Implicit Method for Pressure Linked Equations technique was used to solve the governing equations and discretized using the finite volume method. The simulated results show that the use of a finned tube heat exchanger resulted in an improvement ratio between (2.3) and (3.1). The coefficient of convective heat transfer increased numerically as the volume concentration and Reynolds number increased. The heat transfer coefficient and thermal conductivity rise by 20% and 4.7%, respectively, at a volume concentration of 5%.

Keywords

• Double pipe heat exchanger
• Extended surface
• Nanofluid