How can i define the parameters? #499

Songyihu · 2024-03-06T02:12:10Z

Songyihu
Mar 6, 2024

Dear Francesco Witte:
Thank you for open-sourcing your great work! I'm trying to solve some engineering problems in thermodynamics with TESPy, but I'm having some problems with it.
The number of parameters is fixed when I create a network, but I don't know which parameters to set. The code below is an example of what I'm simulating, I'm sorry it has some Chinese set up in it, but that shouldn't matter. The network needs 250 parameters, but I've provided 259. How do I reasonably set the correct parameters for a beginner? I would be very appreciate if you could give me some advice.

`from tespy.components import Sink, Source, HeatExchanger
from tespy.connections import Connection
from tespy.networks import Network
from tespy.components import Drum, HeatExchanger, Sink, Source, Pump, Desuperheater, Splitter, Merge, DropletSeparator

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

w_source = Source('水源')
g_source = Source('热烟气')
s_sourceH = Source('高压缸蒸汽输入')

s_sink1 = Sink('蒸汽输出1')
s_sink2 = Sink('蒸汽输出2')
s_sink3 = Sink('蒸汽输出3')
g_sink = Sink('烟气输出')

smqL2 = HeatExchanger('低压省煤器2')
smqL2.set_attr(pr1=0.9967, pr2=0.8926, ttd_u=6.6)
smqI = HeatExchanger('中压省煤器')
smqI.set_attr(pr1=0.9968, pr2=0.9536, ttd_u=10.7)
smqH1 = HeatExchanger('高压省煤器1')
smqH1.set_attr(pr1=0.9968, pr2=0.984, ttd_u=9.9)
smqH2 = HeatExchanger('高压省煤器2')
smqH2.set_attr(pr1=0.9968, pr2=0.977, ttd_u=13.5)
zfqL = HeatExchanger('蒸发器1')
zfqL.set_attr(pr1=0.996, ttd_u=48.4)
zfqI = HeatExchanger('蒸发器2')
zfqI.set_attr(pr1=0.9977, ttd_u=40.2)
zfqH = HeatExchanger('蒸发器3')
zfqH.set_attr(pr1=0.9935, ttd_u=149.4)
zrq1 = HeatExchanger('再热器1')
zrq1.set_attr(pr1=0.9979, pr2=0.9846, ttd_u=35.6)
zrq2 = HeatExchanger('再热器2')
zrq2.set_attr(pr1=0.999, pr2=0.9736, ttd_u=30.1)

grqL1 = Desuperheater('低压过热器1')
grqL1.set_attr(pr1=0.999, pr2=0.9937, ttd_u=8.0)
grqL2 = Desuperheater('低压过热器2')
grqL2.set_attr(pr1=0.999, pr2=0.9667, ttd_u=8.8)
grqI = Desuperheater('中压过热器')
grqI.set_attr(pr1=0.999, pr2=0.983, ttd_u=8.9)
grqH1 = Desuperheater('高压过热器1')
grqH1.set_attr(pr1=0.998, pr2=0.9816, ttd_u=61.3)
grqH2 = Desuperheater('高压过热器2')
grqH2.set_attr(pr1=0.999, pr2=0.97, ttd_u=49.0)

drumL = Drum('低压汽包')
drumI = Drum('中压汽包')
drumH = Drum('高压汽包')

merge1 = Merge('汇合点1', num_in=2)
merge3 = Merge('汇合点3', num_in=2)
merge4 = Merge('汇合点4', num_in=2)

split1 = Splitter('分流点1', num_out=2)
split2 = Splitter('分流点2', num_out=2)
splitDrum = Splitter('汽包分离器',num_out=2)
splitL = Splitter('分流点低压气包', num_out=2)

pumpI = Pump('中压水泵')
pumpH = Pump('高压水泵')
pumpI.set_attr(pr=7.97, eta_s=0.85)
pumpH.set_attr(pr=22.31, eta_s=0.85)

g2 = Connection(w_source, 'out1', smqL2, 'in2')
g3 = Connection(smqL2, 'out2', drumL, 'in1')
g4 = Connection(drumL, 'out1', splitDrum, 'in1')
g5 = Connection(splitDrum, 'out1', zfqL, 'in2')
g6 = Connection(splitDrum, 'out2', splitL, 'in1')
g7 = Connection(zfqL, 'out2', drumL, 'in2')
g8 = Connection(drumL, 'out2', grqL1, 'in2')

r14 = Connection(grqL1, 'out2', grqL2, 'in2')
r15 = Connection(grqL2, 'out2', s_sink3, 'in1')

g9 = Connection(splitL, 'out1', pumpH, 'in1')
g10 = Connection(splitL, 'out2', pumpI, 'in1')

g11 = Connection(pumpH, 'out1', smqH1, 'in2')
g12 = Connection(smqH1, 'out2', smqH2, 'in2')
g13 = Connection(smqH2, 'out2', drumH, 'in1')
r1 = Connection(drumH, 'out1', zfqH, 'in2')
r2 = Connection(zfqH, 'out2', drumH, 'in2')
r3 = Connection(drumH, 'out2', grqH1, 'in2')
r4 = Connection(grqH1, 'out2', grqH2, 'in2')
r5 = Connection(grqH2, 'out2', s_sink1, 'in1')

g14 = Connection(pumpI, 'out1', smqI, 'in2')
g15 = Connection(smqI, 'out2', drumI, 'in1')
r6 = Connection(drumI, 'out1', zfqI, 'in2')
r7 = Connection(zfqI, 'out2', drumI, 'in2')
r8 = Connection(drumI, 'out2', grqI, 'in2')
r9 = Connection(s_sourceH, 'out1', merge1, 'in1')
r10 = Connection(grqI, 'out2', merge1, 'in2')
r11 = Connection(merge1, 'out1', zrq1, 'in2')
r12 = Connection(zrq1, 'out2', zrq2, 'in2')
r13 = Connection(zrq2, 'out2', s_sink2, 'in1')

b1 = Connection(g_source, 'out1', zrq2, 'in1')
b2 = Connection(zrq2, 'out1', grqH2, 'in1')
b3 = Connection(grqH2, 'out1', zrq1, 'in1')
b4 = Connection(zrq1, 'out1', grqH1, 'in1')
b5 = Connection(grqH1, 'out1', zfqH, 'in1')
b6 = Connection(zfqH, 'out1', smqH2, 'in1')
b7 = Connection(smqH2, 'out1', split2, 'in1')
b8 = Connection(split2, 'out1', grqI, 'in1')
b9 = Connection(split2, 'out2', merge4, 'in1')
b10 = Connection(grqI, 'out1', merge4, 'in2')
b11 = Connection(merge4, 'out1', zfqI, 'in1')
b12 = Connection(zfqI, 'out1', grqL2, 'in1')
b13 = Connection(grqL2, 'out1', split1, 'in1')
b14 = Connection(split1, 'out1', smqH1, 'in1')
b15 = Connection(split1, 'out2', smqI, 'in1')
b16 = Connection(smqH1, 'out1', merge3, 'in1')
b17 = Connection(smqI, 'out1', merge3, 'in2')
b18 = Connection(merge3, 'out1', grqL1, 'in1')
b19 = Connection(grqL1, 'out1', zfqL, 'in1')
b20 = Connection(zfqL, 'out1', smqL2, 'in1')
b21 = Connection(smqL2, 'out1', g_sink, 'in1')

nw.add_conns(g2, g3, g4, g5, g6, g7, g8, g9, g10, g11, g12, g13, g14, g15,
r1, r2, r3, r4, r5, r6, r7, r8, r9, r10, r11, r12, r13, r14, r15, b1, b2, b3,
b4, b5, b6, b7, b8, b9, b10, b11, b12, b13, b14, b15, b16, b17, b18, b19,
b20, b21)

g2.set_attr(fluid={'water': 1, 'air':0}, T=84.2, p=15.89, m=101.69)
b1.set_attr(fluid={'water': 0, 'air':1}, p=1.0445, T=202.9, m=622.69)
r9.set_attr(fluid={'water': 1, 'air':0}, T=397.7, p=37.9, m=73.6422)

g5.set_attr(m=13.42462)
g9.set_attr(m=76.814)
b9.set_attr(m=278.584)
b11.set_attr(fluid={'air':1})

b14.set_attr(m=546.5758)

nw.solve("design")
nw.print_results()`

Songyihu · 2024-03-10T09:13:35Z

Songyihu
Mar 10, 2024
Author

Please forget my question above, I just want to know, in a network, is there a clear specification for the way to set parameters? Thanks a lot if you could give me some advice.

0 replies

tub-hofmann · 2024-03-13T13:58:46Z

tub-hofmann
Mar 13, 2024

Your network is huge. As a beginner, you should start with a smaller network and build it up step by step. Then parameter setting and solver stability debugging is much easier.
For a gas turbine, I did a step-by-step creation, you can find here:
https://github.com/tub-hofmann/tespy-gt

0 replies

fwitte · 2024-03-13T16:08:26Z

fwitte
Mar 13, 2024
Maintainer

Please forget my question above, I just want to know, in a network, is there a clear specification for the way to set parameters? Thanks a lot if you could give me some advice.

I am not sure what you want to say with this to be honest. The specifications are fully the designers choice... You have to make sure, that all mass flows, pressure values and enthalpy values can be determined from the combination of your specifications.

0 replies

Songyihu · 2024-03-14T06:26:19Z

Songyihu
Mar 14, 2024
Author

@fwitte @tub-hofmann Thank you for your reply. Yes, it's a very large network, but the network works when I set the heat transfer Q as a configuration parameter for the heat exchanger. However, when I change the parameter Q to other parameters, such as the heat transfer coefficient kA or the temperature difference ttd_u, an error occurs.
"ValueError: Temperature to QT_flash [0 K] must be in range [273.06 K, 647.096 K]"
It really confuses me. What do I need to pay attention to when I want to use other parameters？ I would be very appreciate if you could give me some advice!

5 replies

fwitte Mar 14, 2024
Maintainer

My guess is, that it might be starting value related: The error message is from CoolProp and somewhere a value in two-phase region is tried to be accessed but with a temperature of 0K. That usually only happens, if there is not a valid solution available. Could you create a mini-example, that triggers this behavior? I would try to see, if it is a bug, that can be resolved from the tespy side, or if it is just nothing to do about, because of bad starting values.

Run the simulation using Q and then unset the specification (.set_attr(Q=None)) and instead specify the value of the parameter that should replace Q. Then it is more likely that you can find a solution.

Songyihu Mar 15, 2024
Author

@fwitte Hi, here is the mini-example and the framework picture.

The code is below:

from tespy.components import Sink, Source, HeatExchanger
from tespy.connections import Connection
from tespy.networks import Network
from tespy.tools import document_model
import shutil
from tespy.components import Drum, HeatExchanger, Sink, Source, Pump, Desuperheater, Splitter, Merge, DropletSeparator
from tespy.tools import ComponentProperties as CP 

# initialize the Network
nw = Network(fluids=['H2O', 'O2', 'CO2', 'N2', 'Ar'])
# nw = Network(fluids=['water', 'air'])
nw.set_attr(p_unit='bar', T_unit='C', h_unit='kJ / kg',m_unit="kg / s", iterinfo=True)

# define input and output
s_source = Source('中压蒸汽源')
s_source2 = Source('高压蒸汽源')
s_source3 = Source('高压排汽蒸汽源')
g_source = Source('热烟气')

s_sink = Sink('中压蒸汽输出')
s_sink2 = Sink('高压蒸汽输出')
g_sink = Sink('烟气输出')

# define component
merge1=Merge('汇合点1', num_in=2)
zsqI2=HeatExchanger('再热器2')
grqH2=HeatExchanger('高压过热器2')
zsqI1=HeatExchanger('再热器1')
grqH1=HeatExchanger('高压过热器1')
drumH = Drum('高压汽包')
zfqH = HeatExchanger('高压蒸发器')
smqH2 = HeatExchanger('高压省煤器2')
grqI=HeatExchanger('中压过热器')

# component setting

# zsqI2.set_attr(pr1=0.999210, pr2=0.968935,ttd_l=57.4)
# grqH2.set_attr(pr1=0.999175, pr2=0.964662,ttd_l=102.3 )
# zsqI1.set_attr(pr1=0.998030, pr2=0.982252,ttd_l=147.6)
# grqH1.set_attr(pr1=0.998613, pr2=0.979507,ttd_l=149.4 )
# zfqH.set_attr(pr1=0.993865)
# smqH2.set_attr(pr1=0.996986, pr2=0.973955,ttd_l=42.8 )
# grqI.set_attr(pr1=0.999162, pr2=0.936634,ttd_l=40.2)


zsqI2.set_attr(pr1=0.999210, pr2=0.968935,Q=-7258333.3331000)
grqH2.set_attr(pr1=0.999175, pr2=0.964662,Q=-15147222.221000 )
zsqI1.set_attr(pr1=0.998030, pr2=0.982252,Q=-29880555.561000)
grqH1.set_attr(pr1=0.998613, pr2=0.979507,Q=-43386111.111000)
zfqH.set_attr(pr1=0.993865)
smqH2.set_attr(pr1=0.996986, pr2=0.973955,Q=-28013888.89)
grqI.set_attr(pr1=0.999162, pr2=0.936634,Q=-1513888.889)

##System input setting

label_M4=Connection(s_source, 'out1', grqI, 'in2') 
label_M8=Connection(s_source3, 'out1', merge1, 'in2') 
label_11=Connection(g_source, 'out1', zsqI2, 'in1')
label_H3=Connection(s_source2, 'out1', smqH2, 'in2') 

##System output setting

label_20=Connection(grqI, 'out1', g_sink, 'in1')
label_M7=Connection(zsqI2, 'out2', s_sink, 'in1')
label_H7=Connection(grqH2, 'out2', s_sink2, 'in1') 
##connection setting
label_12=Connection(zsqI2, 'out1', grqH2, 'in1') 
label_M6=Connection(zsqI1,'out2', zsqI2, 'in2') 
label_13=Connection(grqH2, 'out1', zsqI1, 'in1') 
label_M9=Connection(merge1, 'out1', zsqI1,'in2') 
label_H6=Connection(grqH1, 'out2', grqH2, 'in2') 
label_14=Connection(zsqI1, 'out1', grqH1, 'in1') 
label_H5=Connection(drumH, 'out2', grqH1, 'in2') 
label_15=Connection(grqH1, 'out1', zfqH, 'in1')
label_Z5=Connection(drumH, 'out1', zfqH, 'in2') 
label_Z6=Connection(zfqH, 'out2', drumH, 'in2')
label_H4=Connection(smqH2, 'out2', drumH, 'in1') 
label_16=Connection(zfqH, 'out1', smqH2, 'in1') 
label_17=Connection(smqH2, 'out1', grqI, 'in1')
label_M5=Connection(grqI, 'out2', merge1, 'in1')

nw.add_conns(label_11,label_12,label_13,label_14,label_15,label_16,label_17,label_20,label_M4,label_M5,label_M6,label_M7,label_M8,label_M9,label_H3,label_H4,label_H5,label_H6,label_H7,label_Z5,label_Z6)
label_11.set_attr(fluid={'water': 4.39/100, 'O2':17.79/100, 'CO2':3.34/100, 'N2':73.17/100, 'Ar':1.31/100}, p=1.652, T=598.1, m=622.19)

label_H3.set_attr(fluid={'water': 1}, p=111.72, T=244.6, m=76.75)
label_M4.set_attr(fluid={'water': 1}, T=245.4, m=11.37)
label_M8.set_attr(fluid={'water': 1}, p=36.9, T=397, m=73.67)
label_Z6.set_attr(T=318)

nw.solve("design")
nw.print_results()

When i change the parameter Q to ttd_l, the error will raise.

Songyihu Mar 16, 2024
Author

The python version is 3.11; the tespy version is 0.7.1.post1; the coolprop version is 6.6.0

fwitte Mar 16, 2024
Maintainer

Thanks, I'll have a look. If you are interested in joining, the next online user meeting is on Monday 17 CET.

Songyihu Mar 17, 2024
Author

Thank you so much for the invitation to join the online user meeting. I truly appreciate it. However, due to the time difference, the meeting occurs at midnight in my timezone (Beijing time), which makes it challenging for me to attend. Thank you for your understanding, best regards!

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How can i define the parameters? #499

Songyihu Mar 6, 2024

Replies: 4 comments · 5 replies

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Songyihu
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Songyihu
Mar 10, 2024
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Mar 13, 2024

fwitte
Mar 13, 2024
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Songyihu
Mar 14, 2024
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fwitte Mar 14, 2024
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Songyihu Mar 15, 2024
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Songyihu Mar 17, 2024
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