Flow field in pressure-swirl injector based on vof interface tracking method and experimental inestigation
- Paper number
IAC-11,C4,1,16,x11611
- Author
Ms. Liu Juan, College of Aerospace and Materials Engineering, National University of Defense Technology, China
- Coauthor
Prof. Li Qinglian, College of Aerospace and Materials Engineering, National University of Defense Technology, China
- Coauthor
Prof. Zhenguo Wang, National University of Defense Technology, China
- Year
2011
- Abstract
The pressure swirl injector is widely used in aero-engine, boiler and liquid rocket engines, particularly in engines developed in Russia and China. The first theoretical predictions were made in 1948 by Abromvich and got the relationship between liquid sheet cone angle and injector geometry parameter A. But the theoretical formula can’t give the detailed flow field. With the development of numerical simulation, more and more detailed flow field has been unclosed. Experimental results and numerical simulation are used to analyze the flowfield of injectors. Commercial software Fluent is used to give the details with interface tracking method VOF and RNG $\kappa$-$\varepsilon$ turbulence model. A transparent injector, which is made up of acrylic, is used to validate the flow process. Water is used to simulate actual fuel. The injectors analyzed here have diameters between 3 and 6mm, lengths between 15 and 60mm. The pressure drops are between 1.0 and 3.0MPa. The influence of injector length on atomization characteristics are especially analyzed, such as liquid sheet thickness, liquid sheet cone angle and oscillation frequency. Liquid sheet thickness is one of the most important factors in drops formation. The thinner the sheet is, the smaller the liquid drops are. The thicknesses are got through post-processing of numerical results, which are concluded based on the same mass flow rate. The injectors have thicker sheet when they have longer length because of the velocity is smaller at the injector exit. Liquid sheet cone angle can give the distribution area of liquid drops, which influence the mixing of fuel and oxidant. The angles are measured by imaging software from experimental photos. The results show that the longer the injector is, the larger the angle is. It is also validated from numerical results. Velocity and pressure distribution in injectors are analyzed and found that the maximum total pressure loss exists in the convergent section and central post. So, the longer the injector is, the pressure loss is larger so as to decrease the cone angle. Liquid sheet undergoes instable process which is associated with combustion instability. From the numerical results, several hundreds Hz frequency are found when inlet face pressure, mass flow rate and volume of fluid are monitored. These types of instabilities are observed not only inside the injector, but also at an external location. The breakdown of an air-core inside the swirling injector and instantaneous process of liquid filling may explain the instability.
- Abstract document
- Manuscript document
IAC-11,C4,1,16,x11611.pdf (🔒 authorized access only).
To get the manuscript, please contact IAF Secretariat.