INVESTIGATION OF AIR INTAKE DESIGN OF A FIGHTER JET
ASLI BARIŞ
BENGU İREM BAŞER
CANER KUTAMIŞ
Supervisor:
ASST. PROF. İZZET MURAT AKŞİT
INLET OF A JET ENGINE
Figure 1 Schematic drawing of a turbojet engine
INLET OF A JET ENGİNE
2 main objectives of an air inlet:
Figure 2 Schematic drawing of a turbojet engine
Why intake is important?
STABILITY AND SAFETY OF ENGINE (BLADE DISTORTION)
PERFORMANCE AND EFFECTIVENESS
S-SHAPED DUCTS
those qualities stealth becomes
an important parameter.
located inside of the aircraft body.
study on S-shaped ducts.
Figure 3 : F-35 engine inlet duct response to medium wavelength
THEORETICAL BACKGROUND
There are three common parameters to define intake performance and stability:
Mass Flow Rate
intakes is mass flow rate.
flow entering the intake per second.
the type of turbojet or turbofan.
Figure 4 Mass flow rate illustration
MASS FLOW RATE
PRESSURE RECOVERY COEFFICIENT (PR)
Figure 5 Pressure Recovery detailed scheme
DISTORTION COEFFICIENT (DC)
DISTORTION COEFFICIENT (DC)
NUMERICAL APPROACH
NUMERICAL APPROACH
NUMERICAL APPROACH
VALİDATİON OF AGARD DP 3532 AND DP78 WİTH RAE M2129�
Quantity | Description | Value |
L | Duct Length | 45.72cm |
XAIP | Engine face position | 48.39 cm |
Rthroat | Throat radius | 6.44 cm |
RAIP | AIP radius | 7.6 cm |
RCapture | Capture area radius | 7.2 cm |
Table 1 Geometry information of M2129.
Condition | Value |
Freestream Mach Number | 0.21 |
Freestream Total Pressure | 101215.78 Pa |
Freestream Total Temperature | 293 K |
AIP Mach Number | 0.794 |
Pressure Recovery (PR) | 0.92 |
Table 2 Boundary conditions of validation study AGARD
Figure 6 Model 2129 S-duct classic illustration.
Figure 7 DP78 Engine Face Pressure Distributions Experimental and Simulation
Figure 8 Velocity vector of symmetric plane of duct test case 3.1 and simulation.
VALİDATİON STUDY OF “A PARAMETRİC STUDY FOR INTAKE FLOW”�
Figure 9 Face mesh structure of designed inlet 2.5m
Figure 10 Mesh structure of designed inlet
Condition | Value |
Freestream Static Temperature | 290.44 K |
Speed of Sound at Freestream | 341.61 m/s |
Freestream Static Pressure | 98152.27 Pa |
AIP Static Temperature | 277.08 K |
Speed of Sound at AIP | 333.66 |
AIP Static Pressure | 77245.56 |
Mass flow rate | 2.953 |
Property | Experimental Result | Analysis Result |
PR | 0.92 | 0.85 |
Mass flow(kg/s) | 1.476 | 1.494 |
Table 3 Additional information Boundary conditions of validation study
Table 4 Pressure Recovery and Mass flow rate comparison.
Figure 11 Mach contour at symmetric plane
Figure 12 Flow at AIP- Numerical results Figure 13 Flow at AIP- Experimental
RAE M2129 S-DİFFUSER VALİDATİON STUDY�
Figure 14 Geometry of the RAE M2129 S-Shaped
diffuser configuration.
Flow Conditions: |
|
Free stream Mach Number | 0.207 |
Free stream Total Pressure | 103011.2 Pa |
Free Stream Total Temperature | 282.6 K |
Angle of Attack | 0º |
Mass flow ratio Ao/Ac | 2.0425 |
Air mass flow at diffuser | 2.8727 kg/s |
Table 5 Flow conditions
Figure 15 Comparison of instantaneous and time-averaged Mach number distributions in the symmetry plane of the M2129 diffuser
MESH GENERATION
Figure 16 :ANSYS TUTORIAL 12 MESH TOPOLOGY
Figure 17: Z- axis front view
Table 5 : Details of mesh in Fluent Meshing.
Figure 18: ANYS FLUENT WORKBENCH
Figure 19: ANYS FLUENT WORKBENCH
Figure 20 Inflation layers on corner of outlet
Figure 21 Isometric view of S-Duct.
Figure 22 Symmetric view of S-duct
Table 6 Element size, orthogonal quality,
skewness and time variations.
Figure 23 details of AIP
Figure 24 Element size vs orthogonality
Figure 25 Element size vs Time graph of (3182653 cell mesh).
EFFECTIVE PARAMETERS IN OPTIMIZATION
Mass flow rate
Pressure
Angle of attack
PR (Pressure Coefficient)
DC
(Distortion Coefficient)
Table 7 Angle of attack and Pressure Recovery
Figure 26 :Pressure Recovery vs Angle of Attack
Velocity contours on planes
Figure 27 Velocity contours on planes
VELOCİTY VS PLANE NUMBER İN ∝ = 0, 5, 10 DEGREES
Figure 28 Velocity vs plane number
TOTAL PRESSURE VS DİSTANCE
Figure 29 Pressure vs distance
VELOCİTY CONTOURS ON SYMMETRİC PLANE
Figure 30 Velocity contours on symmetric plane
VELOCİTY VECTORS ON SYMMETRİC PLANE
Figure 31 Velocity vectors on symmetric plane
STATİC PRESSURE CONTOURS ON SYMMETRİC PLANE
Figure 32 Static Pressure contours
CONCLUSIONS
In this validation study we dealt with Pressure recovery (PR) and angle of attack. The ratio of the air's total pressure at AIP( aerodynamic interface plane) to the air's total pressure in the freestream is known as the pressure recovery coefficient. Pressure recovery coefficient important in terms of inlet efficiency. It represents the losses total pressure in inlet. The key in designs is to maximize this value because pressure loss is an undesirable effect and reduces efficiency. This value also affects the health of the engine in terms of thrust and stability. In our simulations we repeated the study at different angles of attacks with the same parameters which have the same mesh number.
CONCLUSIONS
According to obtained results PR decreases as the angle of attack increases. This is not a desirable result; however, patterns are similar. There are two important results: First, high inlet performance at small angles of attack. The other is that as the angle of attack increases, PR decreases This project is a preparative study for analyzing secondary flows in the inlet which cause drastic performance drops. CFD analysis allows engineers to collect data and optimize the geometry according to collected data. Because of the time limitation we could not study on optimization, yet it stands as the first steps for future works
QUESTIONS?
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REFERENCES