FLUID DYNAMIC ANALYSIS OF A SWIRL INJECTOR

FLUID DYNAMIC ANALYSIS
OF A SWIRL INJECTOR
Authors: H. Dabin
L. Armas
F. Bacchi
Company Overview
Computational Fluid Dynamic Group
(GFC-FI-UNLP)
Introduction
Types of Injectors
SWIRL Injectors
Advantages:
 LOWER DROP PRESSURE
 LOWER CHAMBER LENGTH
 HOMOGENOUS ATOMIZATION
 COMBUSTION STABILITY
Physics of Atomization
2nd Breakup
23,9 mm
1st Breakup
Continuos flow
Φ: 1,4 mm
Ligaments/
Droplets
Droplets
Mesh
Mesh refinement
Lmín: 20 µm
Mesh Details
Methodology of VOF model
Simulation → Fluent 14
•
•
•
•
•
•
Transient
Pressure based model
Incompressible
Turbulence Models: k-ε Realizable y RSM
Multiphase Model (VOF)→ Fuel & Air
Adaptative time step → t < 1  10−7 s
Goals: Determination of system variables
Ve
Fuel
α
φ
Air
α : Spray Angle
φ : Droplet diameter
ho : Sheet Thickness
Ve : Velocity Exit
Results: flow visualization
Results: flow visualization
Results: flow visualization
Results: Comparison with empiric eq.
4,E+06
PRESION [BAR]
3,E+06
3,E+06
2,E+06
2,E+06
1,E+06
5,E+05
0,E+00
0
0,005
0,01
0,015
0,02
0,025
0,03
0,035
0,03
0,035
CAUDAL MÁSICO [KG/S]
Empírico
numerico
3,00E-04
SMD [M]
2,50E-04
2,00E-04
RSM
1,50E-04
1,00E-04
5,00E-05
0,00E+00
0
0,005
0,01
0,015
0,02
0,025
CAUDAL MÁSICO [KG/S]
Empírico
numerico
empirico corregido
Results: Comparison with empiric eq.
SEMI-ÁNGULO [º]
60
50
RSM
40
30
20
10
0
0
0,005
0,01
0,015
0,02
0,025
0,03
0,035
0,03
0,035
CAUDAL MÁSICO [KG/S]
Series1
numerico
semiempirico
VELOCIDAD DE SALIDA
60,00
50,00
40,00
RSM
30,00
20,00
10,00
0,00
0
0,005
0,01
0,015
0,02
0,025
CAUDAL MÁSICO
Empírico
Numérico
Empírico corregido
Accuracy Vs Time
25
TIEMPO (DÍAS)
20
15
10
5
0
200.000
1.000.000
5.500.000
Nº DE ELEMENTOS
* Procesamiento en AMD A8: 3.6 GHz, 16 Gb RAM (4 núcleos en paralelo)
** Modelos K-ℰ
from VOF to DPM
DPM
VOF
Continuous Flow
Ligaments /
droplets
Droplets
3D Model with DPM
Application of DPM: Film Cooling
Conclusions
→ The process of atomization requires great CPU cost.
→ The goal of capture the process of atomization was reached
succesfully.
→ Comparing different models, the RSM one was the most efficient.
→ DPM approach results in a very interesting way to model the second
breakup. It also could be use for film cooling applications
Future Works
Experimental validation
Continue with Film cooling
Multiple injectors
Combustion Simulation
Thanks for your attention !