83 lines
2.8 KiB
Python
83 lines
2.8 KiB
Python
""" A combustor. Two separate stream - one pure methane and the other
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air, both at 300 K and 1 atm flow into an adiabatic combustor where
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they mix. We are interested in the steady-state burning
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solution. Since at 300 K no reaction will occur between methane and
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air, we need to use an 'igniter' to initiate the chemistry. A simple
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igniter is a pulsed flow of atomic hydrogen. After the igniter is
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turned off, the system approaches the steady burning solution."""
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from Cantera import *
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from Cantera.Reactor import *
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from Cantera.Func import *
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# use reaction mechanism GRI-Mech 3.0
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gas = GRI30()
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# create a reservoir for the fuel inlet, and set to pure methane.
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gas.set(T = 300.0, P = OneAtm, X = 'CH4:1.0')
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fuel_in = Reservoir(gas)
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fuel_mw = gas.meanMolarMass()
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# use predefined function Air() for the air inlet
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air = Air()
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air_in = Reservoir(air)
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air_mw = air.meanMolarMass()
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# to ignite the fuel/air mixture, we'll introduce a pulse of radicals.
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# The steady-state behavior is independent of how we do this, so we'll
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# just use a stream of pure atomic hydrogen.
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gas.set(T = 300.0, P = OneAtm, X = 'H:1.0')
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igniter = Reservoir(gas)
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# create the combustor, and fill it in initially with N2
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gas.set(T = 300.0, P = OneAtm, X = 'N2:1.0')
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combustor = Reactor(contents = gas, volume = 1.0)
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# create a reservoir for the exhaust
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exhaust = Reservoir(gas)
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# lean combustion, phi = 0.5
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equiv_ratio = 0.5
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# compute fuel and air mass flow rates
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factor = 0.1
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air_mdot = factor*9.52*air_mw
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fuel_mdot = factor*equiv_ratio*fuel_mw
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# create and install the mass flow controllers. Controllers
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# m1 and m2 provide constant mass flow rates, and m3 provides
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# a short Gaussian pulse only to ignite the mixture
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m1 = MassFlowController(upstream = fuel_in,
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downstream = combustor, mdot = fuel_mdot)
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# note that this connects two reactors with different reaction
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# mechanisms and different numbers of species. Downstream and upstream
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# species are matched by name.
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m2 = MassFlowController(upstream = air_in,
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downstream = combustor, mdot = air_mdot)
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# The igniter will use a Guassiam 'functor' object to specify the
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# time-dependent igniter mass flow rate.
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igniter_mdot = Gaussian(t0 = 1.0, FWHM = 0.2, A = 0.1)
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m3 = MassFlowController(upstream = igniter,
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downstream = combustor, mdot = igniter_mdot)
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# put a valve on the exhaust line to regulate the pressure
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v = Valve(upstream = combustor, downstream = exhaust, Kv = 1.0)
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# the simulation only contains one reactor
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sim = ReactorNet([combustor])
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# take single steps to 6 s, writing the results to a CSV file
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# for later plotting.
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tfinal = 6.0
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tnow = 0.0
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f = open('combustor.csv','w')
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while tnow < tfinal:
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tnow = sim.step(tfinal)
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tres = combustor.mass()/v.massFlowRate()
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writeCSV(f, [tnow, combustor.temperature(), tres]
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+list(combustor.moleFractions()))
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f.close()
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