Session: 04-26 Atomization and Spray Combustion II
Paper Number: 126587
126587 - An Enhanced Predictive Method for Large Droplet Breakage Based on the Discrete Particle Model
In a combustion chamber using liquid fuel, the fuel is injected into the flame tube in the form of jets or liquid films. Subsequently, the liquid surfaces peel off large liquid droplets (100-200mm) and liquid ligaments, which then break into smaller droplets (10-50mm) and disperse within the combustion zone with the airflow. At the same Weber number, despite the similar breakup mode of large and small liquid droplets, after the initial fracture of large droplets, the remaining large droplet diameters remain significantly high, leading to a higher Weber number. Consequently, the processes and outcomes of large droplet and small droplet fragmentation differ significantly.
The Discrete Particle Model (DPM) serves as a widely employed tool for simulating droplet breakup phenomena within combustion chambers. Nevertheless, it faces constraints in accurately forecasting the spatial distribution of smaller droplets when dealing with larger droplets, particularly those exceeding a diameter of 200 mm. This limitation arises from the singular "parcel" approach used to represent substantial droplets, which falls short of capturing the intricate dynamics of their deformation and fragmentation processes.
In the course of our investigation, we leveraged Large Eddy Simulation (LES) in conjunction with Volume of Fluid (VOF) and Adaptive Mesh Refinement (AMR) technology to conduct direct numerical simulations on droplets with a 200 mm diameter, spanning a Weber number range from 20 to 120. The results exhibited an concurrence with experimental data. Our analysis of droplet fragmentation across various Weber numbers unveiled a staged fragmentation process, with each stage featuring a distinct breakup mode dictated by the Weber number.
Drawing from these findings, we put forward a multi-parcel injection method and established breakup models for diverse modes, all grounded in the DPM framework. The outcomes demonstrated effective predictive capabilities regarding the spatial distribution of smaller droplets post-fragmentation, closely aligning with the results from direct numerical simulations. This research presents a pragmatic solution for the prediction of large droplet breakup when employing the DPM approach.
Presenting Author: Ju Hongyu Northwestern Polytechnical University
Presenting Author Biography: I am Ju Hongyu, a doctoral candidate holding both bachelor's and master's degrees in Aerospace from Northwestern Polytechnical University. My current research focus lies in the development of a simulation model for aeroengine combustion chamber sprays.
Authors:
Ju Hongyu Northwestern Polytechnical UniversitySuo Jianqin Northwestern Polytechnical University
Li Yue Northwestern Polytechnical University
An Enhanced Predictive Method for Large Droplet Breakage Based on the Discrete Particle Model
Paper Type
Technical Paper Publication