Week 9 - Senstivity Analysis Assignment

import sys
import numpy as np
import cantera as ct
import matplotlib.pyplot as plt

gas = ct.Solution('gri30.xml')
T = 1500
P = ct.one_atm
gas.TPX = T,P,{'CH4':1,'O2':2,'N2':7.52}
r = ct.IdealGasConstPressureReactor(gas,name = 'R1')
sim = ct.ReactorNet([r])
no_rxn = gas.n_reactions

for i in range(no_rxn):
r.add_sensitivity_reaction(i)
sim.rtol = 1e-6
sim.atol = 1e-15
sense=final=[]
rxn = []
maxi = [0]*no_rxn
maxi_1 = []

sim.rtol_sensitivity = 1e-6
sim.atol_sensitivity = 1e-6

states = ct.SolutionArray(gas,extra=['t','s2'])

for t in np.arange(0, 2e-3, 5e-6):
sim.advance(t)

for j in range(no_rxn):
s = sim.sensitivity(1,j)
states.append(r.thermo.state, t = 1000*t,s2=s)

if (np.abs(s) > np.abs(maxi[j])):
maxi[j] = s

maxi_1 = np.copy(maxi)
maxi_1.sort()
left_ptr = 0
right_ptr = len(maxi_1)-1
ctr = 0

while (ctr<10):
if np.abs(maxi_1[left_ptr])>np.abs(maxi_1[left_ptr]):

final.append(maxi_1[left_ptr])
left_ptr += 1
ctr = ctr+1
else:
final.append(maxi_1[right_ptr])
right_ptr = right_ptr - 1
ctr = ctr + 1

ctr = 0
final.reverse()
rxn.reverse()

while(ctr<10):
index = maxi.index(final[ctr])
rxn.append(sim.sensitivity_parameter_name(index))
ctr += 1

print(final)
plt.figure(1)
plt.barh(rxn,final)
plt.xlabel('Temp sensitivity')
plt.ylabel('reactions')
plt.show()

result:

from the sensitivity plot it can be clearly seen that reaction with highest positive and negative sensitivity

ths means if the rate of reaction increased ,the state temparature increases and we can obtain lesser ignition delay

also if we increase the rate of second reaction state temparature decreases and ignition delay increases