147 lines
4.3 KiB
Python
147 lines
4.3 KiB
Python
#
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# FIXED_T_FLAME - A burner-stabilized, premixed methane/air flat flame
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# with multicomponent transport properties and a specified
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# temperature profile
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#
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from Cantera import *
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from Cantera.OneD import *
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from Cantera.OneD.BurnerFlame import BurnerFlame
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from string import atof
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# read temperature vs. position data from a file.
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# The file is assumed to have one z, T pair per line, separated by a comma.
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def getTempData(filename):
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# open the file containing the temperature data for reading
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f = open(filename)
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z = []
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t = []
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lines = f.readlines()
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# check for unix/Windows/Mac line ending problems
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if len(lines) == 1:
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print 'Warning: only one line found. Possible text file line-ending'
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print 'problem?'
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print 'The one line found is: ',lines[0]
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for line in lines:
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if line[0] == '#': # use '#' as the comment character
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pass
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else:
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try:
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zval, tval = line.split(',')
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z.append(atof(zval))
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t.append(atof(tval))
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except:
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pass
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print 'read',len(z),'temperature values.'
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f.close()
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# convert z values into non-dimensional relative positions.
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n = len(z)
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zmax = z[n-1]
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for i in range(n):
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z[i] = z[i]/zmax
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return [z,t]
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################################################################
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#
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# parameter values
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#
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p = OneAtm # pressure
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tburner = 373.7 # burner temperature
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mdot = 0.04 # kg/m^2/s
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comp = 'CH4:0.65, O2:1, N2:3.76' # premixed gas composition
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# The solution domain is chosen to be 1 cm, and a point very near the
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# downstream boundary is added to help with the zero-gradient boundary
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# condition at this boundary.
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initial_grid = [0.0, 0.0025, 0.005, 0.0075, 0.0099, 0.01] # m
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tol_ss = [1.0e-5, 1.0e-9] # [rtol atol] for steady-state
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# problem
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tol_ts = [1.0e-5, 1.0e-4] # [rtol atol] for time stepping
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loglevel = 1 # amount of diagnostic output (0
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# to 5)
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refine_grid = 1 # 1 to enable refinement, 0 to
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# disable
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################ create the gas object ########################
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#
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# This object will be used to evaluate all thermodynamic, kinetic, and
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# transport properties. It is created with two transport managers, to
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# enable switching from mixture-averaged to multicomponent transport
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# on the last solution.
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gas = GRI30('Mix')
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gas.addTransportModel('Multi')
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# set its state to that of the unburned gas at the burner
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gas.setState_TPX(tburner, p, comp)
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# create the BurnerFlame object.
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f = BurnerFlame(gas = gas, grid = initial_grid)
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# set the properties at the burner
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f.burner.set(massflux = mdot, mole_fractions = comp, temperature = tburner)
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# read in the fixed temperature profile
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[zloc, tvalues] = getTempData('tdata.csv')
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# set the temperature profile to the values read in
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f.flame.setFixedTempProfile(zloc, tvalues)
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f.set(tol = tol_ss, tol_time = tol_ts)
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# show the initial estimate for the solution
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f.showSolution()
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# don't solve the energy equation
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f.set(energy = 'off')
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# first solve the flame with mixture-averaged transport properties
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f.setRefineCriteria(ratio = 3.0, slope = 0.3, curve = 1)
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f.setMaxJacAge(50, 50)
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f.setTimeStep(1.0e-5, [1, 2, 5, 10, 20])
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f.solve(loglevel, refine_grid)
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f.save('ch4_flame_fixed_T.xml','mixav',
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'solution with mixture-averaged transport')
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gas.switchTransportModel('Multi')
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f.flame.setTransportModel(gas)
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f.setRefineCriteria(ratio = 3.0, slope = 0.1, curve = 0.2)
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f.solve(loglevel, refine_grid)
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f.save('ch4_flame_fixed_T.xml','multi',
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'solution with multicomponent transport')
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# write the velocity, temperature, density, and mole fractions to a CSV file
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z = f.flame.grid()
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T = f.T()
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u = f.u()
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V = f.V()
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fcsv = open('flame_fixed_T.csv','w')
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writeCSV(fcsv, ['z (m)', 'u (m/s)', 'V (1/s)', 'T (K)', 'rho (kg/m3)']
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+ list(gas.speciesNames()))
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for n in range(f.flame.nPoints()):
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f.setGasState(n)
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writeCSV(fcsv, [z[n], u[n], V[n], T[n], gas.density()]
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+list(gas.moleFractions()))
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fcsv.close()
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print 'solution saved to flame_fixed_T.csv'
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f.showStats()
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