Aeroengine Fuel Atomization Prediction via VOF-DPM Coupling
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Solution Overview
Problem
Current methods for simulating the atomization process of aeroengine fuels are inefficient and lack accuracy, particularly in capturing the complex interactions and breakup mechanisms of droplets in combustion chambers, leading to high computational burdens and low accuracy in predicting performance.
Innovation Solution
A performance prediction method and system that establishes a 3D geometric model and physical fuel-gas-droplet multiphase flow model, using a combination of finite volume method, volume of fluid, discrete dynamic model, and smoothed discrete particle hydrodynamics to track the gas-liquid interface and simulate droplet interactions, transforming droplets into Lagrangian particles for reduced computational burden and improved accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Eulerian interface tracking method is used to simulate the whole atomization process, then the accuracy of reproducing liquid surface fluctuations and droplet generation is improved, but the computational burden becomes excessively high and the method is hardly applicable to real aeroengines
Solution Approach 1:
The atomization process is segmented into two distinct stages: primary atomization (liquid column/film breakup) simulated using Eulerian interface tracking, and secondary atomization (droplet breakup) simulated using Lagrangian particle tracking. This segmentation allows each method to be applied only where it is most effective, reducing overall computational burden while maintaining accuracy in both stages
Solution Approach 2:
A coupled VOF-DPM method is introduced as an intermediary approach, where the VOF method tracks the gas-liquid interface during primary atomization and generates droplet distributions, which then serve as initial conditions for DPM-based secondary atomization simulation. This intermediary coupling enables seamless transition between the two methods
2Productivity
If the Lagrangian particle dynamic method is used to simulate droplet breakup, then the computational burden is reduced, but the accuracy in describing the real jet breakup process and investigating atomization mechanisms is insufficient
Solution Approach 1:
The Eulerian VOF method is used to perform preliminary simulation of the primary atomization process, accurately capturing the jet breakup and droplet formation mechanisms before transitioning to Lagrangian particle tracking. This preliminary action ensures that the initial droplet distribution and flow field are accurately established, enabling subsequent Lagrangian simulation to maintain high accuracy
3Productivity
If the VOF-DPM coupled method is used to describe the whole atomization process, then the calculation efficiency is improved compared to complete interface tracking, but the fine-grained tracking of numerous small droplets still consumes lots of resources and collision details cannot be obtained
Solution Approach 1:
Different tracking methodologies are applied to different regions and stages of the atomization process: Eulerian VOF tracking is applied to the liquid column and film regions during primary atomization where interface dynamics are critical, while Lagrangian DPM tracking is applied to the dispersed droplet region during secondary atomization. This local quality differentiation optimizes resource allocation by applying fine-grained tracking only where necessary
Data Source
AI summary
A performance prediction method and system for a whole atomization process of an aeroengine fuel. The method includes: establishing a physical fuel-gas-droplet multiphase flow model; obtaining a central velocity field and a fluid volume fraction distribution of meshes with a finite volume method (FVM) based on the physical fuel-gas-droplet multiphase flow model; defining a gas and a liquid according to the central velocity field and the fluid volume fraction distribution; performing mesh refinement on the gas-liquid two-phase interface with an orthogonal adaptive Cartesian mesh method; transforming droplets less than a specified size in the atomization process into Lagrangian particle points; and performing calculation on different volume fractions for the Lagrangian particles included in the meshes to obtain flow field data and droplet data on different time nodes. The present disclosure has the advantages of less calculation burden, higher stability, adjustable liquid properties, trackable droplet trajectories, and so on.