cfd analysis of flow inside the poppet valve duct system

CONFIDENTIALHi-Tech Outsourcing ServicesHi-Tech House, Gurukul, Ahmedabad-380 052, Gujarat, India.Contact: +91-794-000-3237Website: www.hitechos.com | www.hitechcaddservices.com

15 April, 2013

CFD analysis of flow inside the Poppet valve duct system

Prepared by: Rahul Shukla

Reviewed by: Mehul Patel

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Objective

• CFD simulation of air-fuel mixture flow inside the RTO poppet valve duct

system, for the visualization of flow pattern and analysis of flow properties

distribution.

2Hi-Tech Outsourcing ServicesHi-Tech House, Gurukul, Ahmedabad-380 052, Gujarat, India.Contact: +91-794-000-3237Website: www.hitechos.com | www.hitechcaddservices.com

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Summary/ Conclusion

• In this report, the results for the CFD analysis of air-fuel mixture flow inside the RTO poppet valve duct system, for Time-2 configuration is presented.

• For the above purpose, incompressible flow model with species transport in ANSYS FLUENT is used.

• The flow profile obtained at duct outlet from the previous simulation in the system-fan duct is implemented as inlet boundary condition for the current simulation.

• The outlet boundary is extended in order to ensure that the numerical solution is not affected by the duct exit boundary condition.

• Comparatively higher fuel mass fraction is observed in the flow coming out of far end duct outlets. This is due to the fact that the velocity and fuel mass fraction distribution at inlet is not uniform.

• Horizontal stratification of fuel mass fraction is observed in the main duct, which implies that the convection effect is significantly more dominant than diffusion mixing.


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CAD Model


Air-fuel mixture Inlet

Flow exit to chamber

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Meshing Information


Nodes 1,825,590Elements 10,272,111

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Mathematical Model


• For incompressible flow simulation of air with fuel injection and turbulence modeling, following equations are used:

o Conservation of mass:

o Conservation of momentum:

o Conservation of energy:

o Realizable k-epsilon turbulence model with standard wall function is used for

turbulence modeling.

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Input Parameters• Fluid properties:

• Mixture Inlet:


Fluid: Air

Density 0.0462 lb/cf

Fluid: Fuel

Density 0.046 lb/cf

Velocity

Flow profile obtained at duct outlet from the previous simulation performed for the system-fan duct is implemented as inlet boundary condition.

Pressure

Temperature

Fuel mass fraction

Turbulence Parameters

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Boundary Conditions


Mixture Inlet: Flow properties are extracted on inlet patch, from previous simulation.

Outlet: Calculated from the extended domain.

Velocity profile at inlet

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Results: Velocity Distribution


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Velocity profile at duct outlets is not uniform.

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Results: Velocity Vector


Large recirculation zone is created in the main entrance duct.

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In all duct outlets, large recirculation zone is observed.

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Results: Relative Pressure Distribution


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Results: Fuel Mass Fraction


Fuel Mass Fraction

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Fuel Mass Fraction

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Due to non uniform fuel mass fraction observed at inlet, a low fuel content area is created here.

Fuel Mass Fraction

From top view, species content stratification is observed.

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Higher fuel mass fraction is observed in the far end duct outlet.Fuel Mass Fraction

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Results


Inlet Exit-1 Exit-2 Exit-3 Exit-4

Velocity (m/sec)(Area weighted average) 20.10 21.53 19.50 21.78 24.47

Mass flow rate (kg/sec) 23.96 5.77 5.17 6.39 6.64

Fuel mass fraction(Area weighted average) 0.001698 0.001405 0.001377 0.001491 0.001672

Inlet

Exit-4

Exit-3

Exit-2

Exit-1

cfd analysis of flow inside the poppet valve duct system

Documents

fuel flow

fuel mixture flow

cfd analysis of flow

systemfan duct

main duct

mixture inlet flow exit

incompressible flow

rto poppet valve duct