Problems with drum simulation

[icarofvilasboas]

Problems with drum simulation
Hi, I'm studying about tespy and I had problems with drum simulation. For example, below I wrote a case study on a diesel engine exhaust gas recovery boiler and I always get the Singularity in jacobian matrix error. I tried to apply the starting values tutorial ideas, but the problem remains the same. Can you help me?

from tespy.components import Drum, HeatExchanger, Sink, Source
from tespy.networks import Network
from tespy.connections.connection import Connection
from CoolProp.CoolProp import PropsSI as PSI

drum = Drum('drum')
pre = HeatExchanger('preheater')
evap = HeatExchanger('evaporator')
w_source = Source('water source')
w_sink = Sink('water sink')

g_source = Source('gas source')
g_sink = Sink('gas sink')

nw = Network(fluids=['Water', 'air'])
nw.set_attr(p_unit='bar', T_unit='C', h_unit='kJ / kg', iterinfo=True)

# main flux
c1 = Connection(w_source, 'out1', pre, 'in1', label='1')
c2 = Connection(pre, 'out1', drum, 'in1', label='2')
c3 = Connection(drum, 'out1', evap, 'in1', label='3')
c4 = Connection(evap, 'out1', drum, 'in2', label='4')
c5 = Connection(drum, 'out2', w_sink, 'in1', label='5')

nw.add_conns(c1, c2, c3, c4, c5)

# gas flux
cg1 = Connection(g_source, 'out1', evap, 'in2', label='g1')
cg2 = Connection(evap, 'out2', pre, 'in2', label='g2')
cg3 = Connection(pre, 'out2', g_sink, 'in1', label='g3')

nw.add_conns(cg1, cg2, cg3)

# component parameters
pre.set_attr(pr1=0.96, pr2=0.96)
evap.set_attr(pr1=0.96, pr2=0.96)

# fixed parameters
# water from pump
c1.set_attr(fluid={'Water': 1, 'air':0}, p=15, T=45)
# flue gas from diesel engines
cg1.set_attr(fluid={'Water': 0, 'air': 1}, m=21.42, T=231.18)

# project parameters
# water after preheater
c2.set_attr(Td_bp=-2)
# ttdl at preheater
pre.set_attr(ttd_u=5)
# water after evaporator
c4.set_attr(Td_bp=2)


nw.solve('design')

[fwitte]

Hi @icarofvilasboas,

I am out of office right now without having my laptop with me.

I try to give you some ideas, but I cannot confirm: You need to connect the heat exchangers correctly, hot side is index 1, which should be the flue gas part. Then pressure information information is missing on the flue gas part (cg1). Finally, the drum implies equality of pressure at all inlets and outlets, therefore you cannot impose the pr2 for the evaporator. Removing it should do the job. Could you give me feedback, if that did work?

Have a nice day

Francesco

[icarofvilasboas]

Hi @fwitte,

Tank you so much for your support. It solved my problem.
Below the correct version, to whom it may concern.

from tespy.components import Drum, HeatExchanger, Sink, Source
from tespy.networks import Network
from tespy.connections.connection import Connection
from CoolProp.CoolProp import PropsSI as PSI

drum = Drum('drum')
pre = HeatExchanger('preheater')
evap = HeatExchanger('evaporator')
w_source = Source('water source')
w_sink = Sink('water sink')

g_source = Source('gas source')
g_sink = Sink('gas sink')

nw = Network(fluids=['Water', 'air'])
nw.set_attr(p_unit='bar', T_unit='C', h_unit='kJ / kg', iterinfo=True)

# main flux
c1 = Connection(w_source, 'out1', pre, 'in2', label='1')
c2 = Connection(pre, 'out2', drum, 'in1', label='2')
c3 = Connection(drum, 'out1', evap, 'in2', label='3')
c4 = Connection(evap, 'out2', drum, 'in2', label='4')
c5 = Connection(drum, 'out2', w_sink, 'in1', label='5')

nw.add_conns(c1, c2, c3, c4, c5)

# gas flux
cg1 = Connection(g_source, 'out1', evap, 'in1', label='g1')
cg2 = Connection(evap, 'out1', pre, 'in1', label='g2')
cg3 = Connection(pre, 'out1', g_sink, 'in1', label='g3')

nw.add_conns(cg1, cg2, cg3)

# component parameters
pre.set_attr(pr1=0.96, pr2=0.96)
evap.set_attr(pr1=0.96)

# fixed parameters
# water from pump
c1.set_attr(fluid={'Water': 1, 'air':0}, p=15, T=45)
# flue gas from diesel engines
cg1.set_attr(fluid={'Water': 0, 'air': 1}, p=1.01325, m=21.42, T=231.18)

# project parameters
# water after preheater
c2.set_attr(Td_bp=-2)
# ttdl at preheater
pre.set_attr(ttd_u=5)
# water after evaporator
c4.set_attr(Td_bp=2)


nw.solve('design')

[fwitte]

Great! If you are planning on simulation of the engine as well, there is a internal combustion engine component by the way. If you need it implemented differently let me know. Maybe we can come up with something.

Cheers

[icarofvilasboas]

Ok! This is very interesting!
I will keep in touch.
Once again, thank you very much.