Numerical evaluation of heat transfer parameters in shell and tube exchangers using water-based TiO2 nanoparticles

Abstract

The objective of this research is to evaluate, through a numerical simulation, the heat transfer parameters using a mixture of water and 5% nanoparticle (TiO2) as hot fluid in a tube and shell type heat exchanger. For this, the thermal equipment was designed with 13 tubes with internal and external diameters of 0.004 and 0.006 m respectively, shell diameter 0.05 m, one passage through the tubes and one passage through the shell and with 5 deflectors. The material of the tubes is copper and the shell is steel, the working fluids used in the research are water as cold fluid (tube side) and 5% TiO2 nanoparticle mixture as hot fluid (shell side). It was obtained that the exit temperatures for increasing the hot flow of 0.0208 kg/s, 0.0250 kg/s and 0.0375 kg/s, maintaining the cold fluid constant, the temperatures vary between 2.5% and 4.4% for the cold flow and between 5% and 10% for hot flow. Regarding the velocity field, a uniform behavior was observed between the baffles, that is, it is not affected by the fluid flow in the heat exchanger, which is an indicator that the design is efficient. This conclusion is reinforced with the uniform pressure field in the inside of the shell. The heat transfer parameters evaluated were the heat flux increases and this due to the presence of the nanoparticle in the order of 17.6%, the convective coefficient on the side of the tubes increased by 1.2% and a decrease in the overall heat transfer coefficient. heat transfer which decreases by 37.8%.