Choice of inlets of combustion chamber affects simulation convergence

[tub-hofmann]

https://tespy.readthedocs.io/en/main/api/components.html#tespy.components.combustion.base.CombustionChamber

The note on combustion chamber reads:

The fuel and the air components can be connected to either of the inlets.

But changing the topology of the inlets (air from in1 to in2, and fuel from in2 to in1) results in abort of calculation. No convergence.

from tespy.networks import Network
from tespy.components import (Sink, Source, CombustionChamber)
from tespy.connections import Connection

# fluids
air = {'O2': 0.2, 'N2': 0.8}
fuel = {'CH4': 1}

# network
combustion = Network(T_unit='C', p_unit='bar', h_unit='kJ / kg', m_unit='kg / s')

# components
src_air = Source('air-source')
src_fuel = Source('fuel-source')
snk_fluegas = Sink('flue-gas-sink')
cmp_cc = CombustionChamber('combustion chamber')

# connection
c01 = Connection(src_air, 'out1', cmp_cc, 'in1')
c02 = Connection(src_fuel, 'out1', cmp_cc, 'in2')
c03 = Connection(cmp_cc, 'out1', snk_fluegas, 'in1')

combustion.add_conns(c01, c02, c03)

# parameters

# components
cmp_cc.set_attr(lamb=1.05)

# connections
c01.set_attr(p=1, T=25, fluid=air)
c02.set_attr(m=1, T=25, fluid=fuel)

# solve
combustion.solve(mode='design')
combustion.print_results()

#changing topology of combustion chamber inlets
combustion.del_conns(c01, c02, c03)

c01 = Connection(src_air, 'out1', cmp_cc, 'in2')
c02 = Connection(src_fuel, 'out1', cmp_cc, 'in1')
c03 = Connection(cmp_cc, 'out1', snk_fluegas, 'in1')

combustion.add_conns(c01, c02, c03)

# parameters

# components
cmp_cc.set_attr(lamb=1.05)

# connections
c01.set_attr(p=1, T=25, fluid=air)
c02.set_attr(m=1, T=25, fluid=fuel)

# solve
combustion.solve(mode='design')
combustion.print_results()

[fwitte]

Hi @tub-hofmann,

thanks for the hint, I have found the bug, #483 resolves it. I'll upload one more version to pypi then... ;)

Best