numeric simulation of a pig move inside service pipes

8/17/2019 Numeric simulation of a pig move inside service pipes

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NUMERIC SIMULATION OF A PIGMOVE INSIDE SERVICE PIPES

Dr.-Ing. Max Suell Dutra

M.Sc. (e. c.) John Faber Archila Diaz

Robotics Laboratory

COPPE/UFRJ


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Index

• LabRob Presentation• Problem Description

• Methodology

• Mathematical Models

• Simulations

• Conclusion

• References


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Robotics Laboratory UFRJ

• The Robotics Laboratory (LabRob) is part of thepostgraduate program in mechanical engineeringof Institute Alberto Luiz Coimbra of postgraduate

and investigation of engineering, COPPE/UFRJ,is linked to the sector of the machine design and

is specialized in development of products in thearea of mechatronics.

http://www.labrob.coppe.ufrj.br/


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Robotics Laboratory

• The LabRob works with kinematical anddynamical analyses, virtual prototypes, technicalfeasibility studies, design, construction and

testing of mechanical systems.

www.labrob.coppe.ufrj.br/


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Problem Description

• The pipelines correspond to the veins andarteries of our cities and industries.

• Its use is universal and has records of first pipesto 4000 B C.

Distribution of pipes in the world (Bueno, 2007)


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Problem Description

• In the U.S. it is estimated that 80000km of pipelines to be rehabilitated inthe next 9 years. In other countries

like Russia approximately 20% of oiland gas pipelines are near the end

of life. In 15 years 50% of allpipelines in the world come to the

end of its operation.

• In Brazil it is estimated that thereare more than 30000 km ofpipelines buried.


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Problem Description

• The maintenance of pipelinesis a part of the program of

integrity assurance, which arebased on data frominspections of service lines.

• In case of buried pipelinesone of the main tools ofinspection is the PIG

(Pipeline Inspection Gauge)which is used for inspection,maintenance, and is a

procedure standard for gasand oil.

Integrity evaluation process of the threat of external corrosion

(Thomas et al., 2000)


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Problem Description

• The PIGs have several purposes during the travel intothe pipeline, like: cleaning the pipe, removal of liquid,

separation of products and inspection, among others.An operation with PIG demand the evaluation of variousoperational parameters such as maximum and minimumpressures and speed of movement of the pig during the

planning stage and keept certain limits during themonitoring of the operation.


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Methodology

Methodology (ARCHILA et. al., 2008)


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Methodology

CFD Methodology used in this work

– Mathematical Modeling• Kinematics

– Fluid

– PIG

• Dynamics

– Fluid

– PIG

• Solve equations system


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Mathematical Modeling

• Kinematics.

MEDGAZ

OCENSA

OSPAR


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• Kinematics

φ

( ) ( )

( ) ( )

' sin / 2 sin / 2

cos / 2 cos / 2

/ /

i

d

x c c

r y c c

c b c b

φ φ ω

φ φ ω

φ

− −

′ ′= = ′ −

( )

( )

( )

0

0

00

0

0

sin

2

co s

2

t

d i

t

d i

t

d i

cdt

x xc

y y dt

c

dt b

φ ω ω

φ ω ω

φ φ

ω ω

− +

= + +

−

∫

∫

∫


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• DynamicsContinuity equation

θ

0 D dxτ π PA

( )PA A dx x

ρ ∂

+∂

AP dx

x

∂

∂

( ) ( ) 0 Adx AV dxt x

ρ ρ ∂ ∂+ =∂ ∂

1 1dA A dP V A

A dt A P dt A s

∂ ∂= +

∂ ∂

2

1 1d dp

dt a dt

ρ

ρ ρ =

2 2 0P P V V A

V c ct x x A x

ρ ρ ∂ ∂ ∂ ∂

+ + + =∂ ∂ ∂ ∂

2 2 / c a ξ = ( )2

21 1'

a D

t E

ρ ξ ν = + −

Fluid compressibility (Isothermal)

Change of pipe area


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• Dynamics

X

dx

θ

0 D dxτ π PA

( )PA A dx x

ρ ∂

+∂

AP dx

x

∂

∂

s

DV F A dx

Dt ρ =∑

08

f V V τ ρ =

64

Re f =

2

0,9

5,740, 25 log

3, 7 Re D f

ε −

= +

2 53, 073 10 3,14 10 Re f − −= − × + ×

( )0 , 0exp Pc P P µ µ µ = −

1sin

2

V V V V P f V g

t x x Dθ

ρ

∂ ∂ ∂+ = − − −

∂ ∂ ∂

Friction

Viscosity


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• Dynamics

θ

x d L LF dt x x

∂ ∂

= − ∂ ∂ ∑ &

21

2 L mV mgh= −

( )1 2 x aF P P A F = − −∑

( )2

1 22 sin ad xm P P A mg F

dt θ = − − −


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Simulations

• Results


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Simulations

• Results


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Simulations

• Results


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Simulations

• Results


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Simulations

• Results


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Simulations

• Results


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Conclusion

• The solution of the mathematical modeling ofcoupled nonlinear differential equations using the

finite differences in a rectangular grid, withcoordinates of time and position, was presented.

• An algorithm to simulate movement of PIGs in

service lines, modelled using Matlabenvironment, obtaining solutions for differentconfigurations of the pipelines under some

conditions of operation was developed andpresented.


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Conclusion

• The results of the simulations show that thepressure can achieve 1.3 times the operation

pressure. This fact shows the importance of theeffect analysis during the passage of PIGs inservice lines.

• The maximum allowed pressure of operation(PMOA) can be oversteped.

• The minimum conditions of pressure generating

conditions for slack line flow, damaging the pipeor decreasing its life can be achieved and mustbe avoided.


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References

• ARCHILA, J. F. D., DUTRA, M. S., 2008, “NumericSimulation of a PIG move inside service pipes”. In: 3rd

Latin American CFD Meeting Applied to Oil & GasIndustry, Rio de Janeiro, Brasil.

• ARCHILA, J. F. D., DUTRA, M. S., 2008, “PipelinesInspection Robots”. In: Rio Oil & Gas Expo andConference, Rio de Janeiro, Brasil.

• ARCHILA, J. F. D., STUECK, A., DUTRA, M. S., 2008,“Robôs para inspeção de linhas de serviço”. In: V

National Congress of Mechanical Engineering, Salvador,Bahia, Brasil.


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References

• AZEVEDO, L. F., BRAGA, A. M., NIECKELE, A. O.,1997, Relatório final Projeto e Simulação de

Deslocamento de PIGs, Departamento de EngenhariaMecânica Pontifícia Universidade Católica do Rio PUC-Rio, Rio de Janeiro, Brasil.

• BUENO, A. H. S., 2007, Avaliação Integrada deMecanismos de Falha por Corrosão em Dutos, Tese deDoutorado, COPPE/UFRJ, Rio de Janeiro, Brasil.

numeric simulation of a pig move inside service pipes

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