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UNPLUGGING OF HIGH LEVEL WASTE TRANSFER PIPELINES:Method of Characteristics
Stephen Wood DOE Fellow
• At least one cross-site transfer line in Hanford is plugged. Several other pipelines may be partially plugged.
• Pipeline plugging can happen during cross-site slurry pipeline transfers from single shell tanks to double shell tanks.
– Plugged pipelines are difficult to repair and put back into operation. They are often abandoned and new ones are constructed.• Schedule delays• Increased costs
• Unplugging technologies are needed to remove the blockages in transfer lines.
• 149 Single Shell tanks store waste at Hanford – To date seven single-shell tanks have been emptied (ORP
09-006)
Background
NuVision Testing
Results
AcknowledgementsDr. Seckin GokaltunDr. Leonel LagosProfessor George DulikravichDOE/FIU Science & Technology Workforce Development Initiative
Differential Evolution
Method of Characteristics
k=generation=0, n=population size =20
F=mutation=0.8,CR=crossover=0.6
Choose randomly three members of P (α,β,γ)
Generate a random number R;
0<R<1
A
Go to A
R<CR?
Replaces in P
Best member is the optimum
Xik +1 = ∂1Xi
k +∂2 α + F(β − γ )[ ]
U Xik +1( )< U Xi
k( )
∂1 = 0∂2 =1
∂1 =1∂2 = 0
Xik +1
Xik
k = k +1
Xik
Convergence?
1- Maximum number of iterations reached2- U(best member) reaches 03- 90% of population hasn’t improved for 10 generations.
YES
YES
NO
NO
NO
YES
Xik =
ith friction _coeff .ithgeom._ loss
=
fik
cgik
U Xik( )= PMax _ Exp. − PMax _ i
k
Minimize
Design Variables
Coded based on algorithm’s presented in EML 5509 Spring 2009
Objective function
is the i-th individual vector of parameters. α, β and γ are three members of the population matrix P. k is the number of generations In the minimization process, if ,
then replaces in the population matrix P.Otherwise, is kept in the population matrix.
Xik
U Xik +1( )< U Xi
k( )
Xik +1
Xik
Xik
is kept in P
Hr(t)
Method of Characteristics Model of 285ft NuVision Test case
Hr(t)
Modified Method of Characteristics Model of 285ft NuVision Test case
Optimized from parameter ranges:f = [ 0.01 : 0.04 ]
cg = [ 0 : 1 ]
20 generations1.67 CPU Hours
@ 1.3 Ghz on Tesla-1285 min clock time
Over estimates peak pressure by 0.01% an
improvement of 0.9%
Peak pressure advanced 0.4% and improvement of 2.6%
f = 0.021cg = 0.3
Basic Differential Equations for Transient Flow
Conclusions & Applications
Derivation of Momentum Equation Derivation of Continuity Equation
By neglecting small terms, using a Darcy-Weisbach friction factor, and simplifying with steady flow assumptions:
By expansion, and grouping of material and restraint conditions for a pipeline anchored throughout:
• The inclusion of a loss factor that accounts for the presence of 90° elbows enhances accuracy of the model.o Peak pressure predictiono Wave form shape
• The use of differential evolution to determine model parameters (e.g. f, cg, m) provides timely solutions which accurately characterize a pipeline.
• Once a pipeline is characterized, appropriate inlet pressures to achieve desired transients can be determined through differential evolution.