Numerical analysis of the use of nanofluids and turbulator on heat transfer properties in double-tube heat exchangers

This study aimed to investigate the effect of using nanofluids and turbulators on the efficiency of two-pipe heat exchangers and compare between co-current and non-co-current flows. Several experiments were conducted at different temperatures and with different concentrations of nanofluids, and the results were evaluated using co-current and non-co-current flows. The results showed that the use of nanofluids has a positive effect on improving heat transfer efficiency. Increasing the concentration of nanoparticles from ۰.۱% to ۰.۷% in all experiments resulted in a significant increase in efficiency. For example, at a temperature of ۶۰ °C and using ۰.۷% nanofluid, the efficiency increased from ۴۴% in the pure water state to ۶۰% in the co-current state and to ۶۵% in the non-co-current state. These results indicate the high potential of nanofluids in improving the performance of heat transfer systems. Nanoparticles with their high thermal conductivity effectively accelerate heat transfer, and this is especially evident at higher concentrations. The turbulator played a very important role in improving the heat transfer efficiency. Using the turbulator, the system efficiency increased significantly, especially in combination with nanofluids with higher concentrations. For example, at ۶۰ °C and using ۰.۳% nanofluid and turbulator, the co-current efficiency increased from ۴۵% to ۵۰% and the non-co-current efficiency increased from ۴۹% to ۵۲%. The use of the turbulator causes turbulent flows inside the tubes, which leads to an increase in system efficiency by reducing the thermal boundary layer and increasing the effective contact of the fluid with the wall. The best conditions for optimizing the performance of the two-tube heat exchanger in this study were the use of ۰.۷% nanofluid and turbulator in non-co-current flow. In this case, the system efficiency reached a maximum value of ۶۵%. This result shows that the simultaneous use of high-concentration nanofluids and turbulators with non-coordinated flow is the most effective method for improving heat transfer.

کلیدواژه ها:

nanofluid ، flow turbulator ، heat transfer ، double-tube heat exchanger ، computational fluid dynamics ، mathematical modeling ، turbulators