CFD – Aerodynamic Analysis

JOSUÉ MARTE GRANADOS RAMOS 965898

LUIS FELIPE PACHECO FLORES 968221

GERARDO BALTIERRA UREÑA 987708

VÍCTOR MANUEL GUTIÉRREZ LÓPEZ 1161698

DANIEL ALFONSO VELÁZQUEZ LECHUGA 1180365

Supermarine Spitfire

• Second World War (Royal Air Force)

• British high performance interceptor fighter aircraft.

• Designed by R.J Michel

• One passenger user.

• Elliptical wings

Supermarine Spitfire Characteristics

Velocity 320 mph (515

km/hr)

length 30 ft (9.14 m)

Wingspan 36 ft 10 in (11.23 m)

Height 10 ft (3.05 m)

Weight 7923 lb (3593 kg)

Weapon capacity (Type E):

• 20 mm Hispano MKII

cannon x2

• 12.7 mm M2 Browning

machine guns x2

• 250 lb bomb x2

Rolls Royce - Merlin Engine

MERLIN XX PERFORMANCE ENGINE

SEA LEVEL PERFORMANCE

Pi = 50 in Hg abs. Pe = 30.0 in Hg abs.

N = 3000 rpm

Supercharger gear ratio: 9.49

ALTITUDE PERFORMANCE @ 20, 000 ft.

Aircraft Velocity = 335 mph.

Pi = 48.24 in Hg abs. Pa = 13.75 in Hg abs.

Pe = 22.3 in Hg abs. N = 3020 rpm

Supercharger gear ratio: 9.49

AIR FLOW

(lb/min)

129.2 147.2

FUEL FLOW 9.48 10.0

SHAFT

HORSEPOWER

1236 1318

BRAKE

HORSEPOWER

1020 1132

• Twin turbocompresor V12 Engine 27 L

• Ethylene glicol coolant

• Shaft speed: 3000 rpm

• 1480 HP at 6000 ft

• Compression ratio 6:1

• Compressor and fuel efficiency improvements.

* There are many different types of Merlin Engine since it has been improved.

Discretization of the model:

Hypermesh

Figure 1.1 CAD model Figure 1.2 Mesh of the surfaceFigure 1.3 Exhaust engine outlet

Figure 1.4 Moving Reference Frame elements

Boundary layer theory

Figure 2.2 Boundary layer finite elements through the surface Figure 2.3 Boundary layer integrated into fluidFigure 2.1 finite elements of two different fluids

Boundary conditions & properties

Zone Type Edit

Inlet velocity inlet v= 143.06 m/s, P=0 Pa

oulet pressure outlet P= 0 Pa

symm symetry -

wall wall -

Figure 2.4 Scaling factor for the model in FLUENT.

Schematic internal structure

Figure 2.5 Internal components of the airplane

Results: Velocity & mass flow

Figure 3.1 Number of iterations in which mass flowconverges

Figure 3.2 Velocity of the fluid contour

Results: dynamic pressure

Figure 3.4 Convergence of residuals

Figure 3.3 absolute dynamic pressure contours through wing’s surface

Countour results: temperature

Figure 3.6 Exhaust valves of the Merlin Engine

Figure 3.5 Absolut temperature contours across the exhaust valves of the engine.

Aerodynamic forces (coefficients)

Drag force – projected

area on z axis.

Lift force – projected

area on y axis.

Liftforce Dragforce

Observations

Weapons contribute to increase the drag force

Density changes at high altitude

Merlin engine was improved in order to achieve better

efficiency

Lift and Drag coefficients are different through the

surface of the aircraft, there are presented the

maximum values.

Total area of the aircraft was considered.

References

White. F (2008). Fluid Mechanics. Mc Graw Hill

Lovesey, A.C (1945). Development of the Rolls-Royce Merlin from 1939 to1945. Retrieved at November 19, 2013 from: http://www.missbardahl.com/engine/hist/rr_merlin_dev.pdf

J. Raymond, R. (2011) Aircraft Engine Performance Analysis at Rolls-Royce ca. 1940. Retrieved at November 28, 2013 from: http://www.enginehistory.org/members/articles/ACEnginePerfAnalysisR-R.shtml

Royal AirForce (2013). Supermarine Spitfire. UK Crown. Retrieved at November 28, 2013 from: http://www.raf.mod.uk/history/supermarinespitfire.cfm