Heat Transfer Enhancement Using Al2O3-MWCNT Hybrid-Nanofluid inside a Tube/Shell Heat Exchanger with Different Tube Shapes

The high demand for compact heat exchangers has led researchers to develop high-quality and energy-efficient heat exchangers at a lower cost than conventional ones. To address this require-ment, the present study focuses on improvements to the tube/shell heat exchanger to maximize the efficiency either by altering the tube's geometrical shape and/or by adding nanoparticles in its heat transfer fluid. Water-based Al2O3-MWCNT hybrid nanofluid is utilized here as a heat transfer fluid. The fluid flows at a high temperature and constant velocity, and the tubes are maintained at a low temperature with various shapes of the tube. The involved transport equations are solved numerically by the finite-element-based computing tool. The results are presented using the stream-lines, isotherms, entropy generation contours, and Nusselt number profiles for various nanoparticles volume fraction 0.01 = ? = 0.04 and Reynolds numbers 2400 = Re = 2700 for the different shaped tubes of the heat exchanger. The results indicate that the heat exchange rate is a growing function of the increasing nanoparticle concentration and velocity of the heat transfer fluid. The diamond-shaped tubes show a better geometric shape for obtaining the superior heat transfer of the heat exchanger. Heat transfer is further enhanced by using the hybrid nanofluid, and the enhancement goes up to 103.07% with a particle concentration of 2%. The corresponding entropy generation is also minimal with the diamond-shaped tubes. The outcome of the study is very significant in the industrial field and can solve many heat transfer problems.

Automated summary

The present study focuses on improving the tube/shell heat exchanger by altering the tube's geometrical shape and/or adding nanoparticles in its heat transfer fluid, aiming to maximize efficiency and energy savings. The results show that increasing the nanoparticle concentration and velocity of the heat transfer fluid can enhance the heat exchange rate, and diamond-shaped tubes exhibit superior heat transfer performance. This study is highly significant in solving many heat transfer problems in the industrial field.