Investigation of Effective Parameters on the Thermo-Hydrodynamic Characteristic of Nanofluid Flow at a Double-Pipe Heat Exchanger with Ultrasonic Assistance

This study analyzes a heat exchanger enhanced with piezoelectric components to produce ultrasonic vibrations using Computational Fluid Dynamics (CFD). The hot fluid, a water-aluminum oxide nanofluid, flows through the inner pipe, while water serves as the cold fluid. Nanofluid concentrations of ۰.۲% to ۰.۸% by volume were investigated. The ultrasonic transducer's effect was modeled as a harmonic time function, and flow turbulence was evaluated using the k-ε turbulence model. The impact of various parameters, including the length of the heat exchanger, the diameter of the outer pipe, the velocity of the incoming fluid, the number of piezoelectrics, and the amplitude and frequency of the waves, on the pressure loss, the Nusselt number, and the overall efficiency of the heat exchanger were investigated. This study introduces a novel approach by applying ultrasonic excitation to the inner tube of a heat exchanger and systematically evaluating both thermal and hydraulic performance. Unlike prior research, which considered a limited set of parameters, this paper examines a broader range of factors, including flow rate, heat exchanger geometry, piezoelectric elements, and wave characteristics. The findings highlight the significant influence of these parameters on overall thermo-hydraulic efficiency. The study revealed that extending the length of the heat exchanger significantly improved heat transfer performance, yielding an approximate ۷۰% enhancement. The simulation data indicate that higher nanoparticle concentrations in the nanofluid enhance heat transfer efficiency, resulting in a ۲۰% increase in systems with piezoelectric elements and a ۹% increase in those without. When the number of piezoelectric elements was increased from ۳ to ۵, an additional ۳۶% improvement in heat transfer was observed under high flow rate conditions. Additionally, the presence of piezoelectric components amplified the nanofluid's impact on heat transfer by ۴۵%. Finally, elevating the amplitude and frequency of the waves further enhanced heat transfer efficiency by ۲۴% and ۶۲%, respectively.

کلیدواژه ها:

Double-pipe heat exchanger ، nanofluid ، Ultrasonic vibrations ، Pressure drop ، Heat Exchanger Efficiency