In a groundbreaking study published in the International Journal of Thermofluids, researchers led by Mohammadreza Asadi from the Mechanical Engineering Department at Sharif University of Technology in Tehran have delved into the fascinating dynamics of droplet impacts on molten phase change materials (PCMs). This research could have significant implications for various industries, including maritime applications, particularly in the realm of thermal energy storage systems.
The core of the study revolves around the impact of acetone droplets on a pool of molten paraffin. This process not only initiates the boiling of the acetone but also solidifies the paraffin in contact with it. The ability to enhance heat transfer between fluids is crucial for many applications, and this research offers a novel approach to improving the efficiency of thermal energy storage systems, which are becoming increasingly vital in maritime operations. As ships and offshore platforms look to optimize energy use and reduce emissions, the findings from this study could play a key role in developing more efficient thermal management systems.
Asadi and his team observed the dynamics of droplet impact under varying conditions, specifically looking at different Weber numbers and temperatures of the molten PCM. They discovered that increasing these parameters led to larger craters and more vigorous jet formations. “An increase in the Weber number or surface temperature leads to a larger crater and higher jet and crown,” Asadi noted, emphasizing the importance of understanding these dynamics for practical applications.
One of the standout features of this research is the use of particle image velocimetry (PIV) and high-speed imaging to capture the velocity field created during the droplet impact. This is the first time such detailed measurements have been taken, providing a fresh perspective on the physical phenomena at play. The results revealed that the maximum velocity occurs at the lowest point of the crater, reaching about 10% of the impact velocity. This insight could be pivotal for engineers designing systems that rely on precise thermal management.
Moreover, the study highlights how the solidified area of paraffin increases with higher Weber numbers and lower surface temperatures. For instance, at a Weber number of 297 and a temperature of 90 °C, the solidified area was found to be 9.3% of that at 65 °C. This information could help in optimizing the materials and conditions used in energy storage systems on ships, where efficient heat transfer can lead to reduced fuel consumption and lower operational costs.
The findings also included the visualization of acetone vapor using Z-type Schlieren imaging, which showed that the evaporation rate of acetone increases with the Weber number. This could open up avenues for further research into how vaporization can be harnessed in maritime applications, potentially leading to innovations in cooling systems or even in the development of new materials that can withstand extreme conditions.
As the maritime industry continues to seek sustainable solutions and improve energy efficiency, the insights from Asadi’s research present exciting opportunities. By enhancing our understanding of droplet dynamics and phase change materials, this work could lead to the development of advanced thermal management systems that not only improve performance but also contribute to a greener future for maritime operations.
