Week 2 Air standard Cycle

Aim:

To create Otto cycle simulator and show it in P-V plot

procedure:

import math
import matplotlib.pyplot as plt

def engine_kinematics(bore,stroke,con_rod,cr,start_crank,end_crank):
	
	
	a=stroke/2
	R=con_rod/a

	v_s=math.pi*(1/4)*pow(bore,2)*stroke
	v_c=v_s/(cr-1)

	sc=math.radians(start_crank)
	ec=math.radians(end_crank)
	num_values=50
	dtheta=(ec-sc)/(num_values-1)
	V=[]

	for i in range(0,num_values):
		theta=sc+i*dtheta
		term1=0.5*(cr-1)
		term2=R+1-math.cos(theta)
		term3=pow(R,2)-pow(math.sin(theta),2)
		term3=pow(term3,0.5)
		V.append((1+term1*(term2-term3))*v_c)
	return V	
	





#inputs
p1=101325
t1=500
gamma=1.4
t3=2300

#Geomentry parametrs
bore=0.1
stroke=0.1
con_rod=0.15
cr=12

#volume calculations
v_s=math.pi/4*pow(bore,2)*stroke
v_c=v_s/(cr-1)
v1=v_s+v_c

#state point 2
v2=v_c
p2=p1*pow(v1,gamma)/pow(v2,gamma)
rhs=p1*v1/t1
t2=p2*v2/rhs

v_comp=engine_kinematics(bore,stroke,con_rod,cr,180,0)
cont=p1*pow(v1,gamma)
p_comp=[]

for v in v_comp:
	p_comp.append(cont/pow(v,gamma))


#state point 3
v3=v2
rhs=p2*v2/t2
p3=rhs*t3/v3

v_expn=engine_kinematics(bore,stroke,con_rod,cr,0,180)
cont=p3*pow(v3,gamma)
p_expn=[]

for v in v_expn:
	p_expn.append(cont/pow(v,gamma))


#state point 4
v4=v1
p4=p3*pow(v3,gamma)/pow(v4,gamma)
t4=v4*p4/rhs

plt.plot([v2,v3],[p2,p3])
plt.plot(v_comp,p_comp)
plt.plot(v_expn,p_expn)
plt.plot([v4,v1],[p4,p1])
plt.xlabel('volume')
plt.ylabel('pressure')
plt.show()

P-V plot as a result of above code: