48 lines
1.5 KiB
Python
48 lines
1.5 KiB
Python
# A CVD example. This example computes the growth rate of a diamond
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#film according to a simplified version of a particular published
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#growth mechanism (see file diamond.cti for details). Only the surface
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#coverage equations are solved here; the gas composition is
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#fixed. (For an example of coupled gas-phase and surface, see
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#catcomb.py.) Atomic hydrogen plays an important role in diamond CVD,
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#and this example computes the growth rate and surface coverages as a
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#function of [H] at the surface for fixed temperature and [CH3].
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from Cantera import *
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import math
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print '\n\b****** CVD Diamond Example ******\n'
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# import the models for the gas and bulk diamond
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g, dbulk = importPhases('diamond.cti',['gas','diamond'])
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# import the model for the diamond (100) surface
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d = importInterface('diamond.cti','diamond_100',phases = [g, dbulk])
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ns = d.nSpecies()
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mw = dbulk.molarMasses()[0]
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t = 1200.0
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x = g.moleFractions()
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p = 20.0*OneAtm/760.0 # 20 Torr
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g.setState_TPX(t, p, x)
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ih = g.speciesIndex('H')
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xh0 = x[ih]
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f = open('diamond.csv','w')
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writeCSV(f, ['H mole Fraction', 'Growth Rate (microns/hour)']+d.speciesNames())
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for n in range(20):
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x[ih] /= 1.4
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g.setState_TPX(t, p, x)
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d.advanceCoverages(10.0) # iintegrate the coverages to steady state
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carbon_dot = d.netProductionRates(phase = dbulk)[0]
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mdot = mw*carbon_dot
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rate = mdot/dbulk.density()
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writeCSV(f,[x[ih],rate*1.0e6*3600.0]+list(d.coverages()))
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f.close()
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print 'H concentration, growth rate, and surface coverages written to file diamond.csv'
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