| Issue |
EPJ Web Conf.
Volume 361, 2026
ASPOWERCN 2024 – The 8th Joint Conference of Aerospace Propulsion and the 44th Aerospace Propulsion Technology Information Society (APTIS) Technical Conference
|
|
|---|---|---|
| Article Number | 08001 | |
| Number of page(s) | 15 | |
| Section | Piston Engine | |
| DOI | https://doi.org/10.1051/epjconf/202636108001 | |
| Published online | 13 April 2026 | |
https://doi.org/10.1051/epjconf/202636108001
Spray and droplets characteristics of air assisted nozzle under extreme low fuel temperature
1 State Key Laboratory of Intelligent Green Vehicle and Mobility, Tsinghua University, Beijing 100084, China
2 Chongqing Zongshen Innovative Technology Research Institute Co., Chongqing 400054, China
* Corresponding author: Xiao Ma, PhD, Tsinghua University, State Key Laboratory of Intelligent Green Vehicle and Mobility, No 30, Shuangqing Road, 100084, Beijing, China. E-mail: This email address is being protected from spambots. You need JavaScript enabled to view it.
Published online: 13 April 2026
Abstract
To extend the range of unmanned aerial vehicles (UAVs), internal combustion engines using aviation kerosene are utilized because of its high efficiency and power density. The air assisted nozzle are used in the engines of UAVs due to the requirement of light weight. But the extreme low temperature at high altitude pose a great challenge to the air assisted nozzle because of the high viscosity and low volatility of fuel under low temperature. In this paper, a cryogenic fuel injection system coupled with an air assisted nozzle are utilized to realize the injection under low fuel temperature down to – 55 °C. The high-speed imaging and Phase Doppler Particle Analyzer (PDPA) technologies are employed to analyze the spray and droplets characteristics. Results showed that large visible droplets come out of the nozzle under low temperature, indicating the incomplete breakup inside the nozzle. The Sauter mean diameter (SMD) significantly increase from 14 μm to 25.4 μm with the fuel temperature decrease from 25°C to – 55°C, leads to deterioration in atomization and evaporation. Furthermore, increasing assisted air injection pressure and duration can reduce the large droplets and improve the atomization. Results indicate that eliminating the large visible droplets is a key issue to improve the atomization performance. The design of fuel storage grooves or threads on the inside surface of the nozzle may reduce the fuel accumulation in the exit of the nozzle and reduce the incomplete breakup.
Key words: air assisted nozzle / low fuel temperature / spray characteristics / droplets measurement / unmanned aerial vehicles (UAVs)
© The Authors, published by EDP Sciences, 2026
This is an Open Access article distributed under the terms of the Creative Commons Attribution License 4.0, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.