def __design_angelino_nozzle(self, design_alt, truncate_ratio, CEA, r_e):
""" Can be a class function, will edit going forwards
"""
(p_atm, T_atm, rho_atm) = gd.standard_atmosphere([design_alt])
PR = CEA.p_c / p_atm
M_e = gd.PR_expansion_mach(PR, CEA.gamma)
expansion_ratio = gd.expansion_ratio(1, M_e, CEA.gamma) #6.64 #8.1273
# print('Exp. ratio: ' + str(expansion_ratio))
# print('PR: ' + str(PR))
A_t = r_e**2 * np.pi / expansion_ratio # max expansion (r_b = 0, r_e**2 >= A_t*expansion_ratio/np.pi)
return plug_nozzle(expansion_ratio,
A_t,
r_e,
CEA.gamma,
CEA.T_c,
CEA.p_c,
CEA.a_c,
CEA.rho_c,
1500,
truncate_ratio=truncate_ratio)
r_e = 0.067 / 2 #0.034 # likely too large
expansion_ratio = 6.64 #8.1273
A_t = r_e**2 * np.pi / expansion_ratio # max expansion (r_b = 0, r_e**2 >= A_t*expansion_ratio/np.pi)
gamma = 1.2381 #np.mean([1.2534,1.2852])
T_c = 2833.63
p_c = 34.474 * 10**5
rho_c = 3.3826
R = (1 - 1 / gamma) * 1.8292 * 1000 #1.8292 1.6196
a_c = np.sqrt(gamma * (1 - 1 / gamma) * 200.07 * T_c)
n = 1000
spike = plug_nozzle(expansion_ratio,
A_t,
r_e,
gamma,
T_c,
p_c,
a_c,
rho_c,
n,
truncate_ratio=1.0)
alts = np.linspace(0, 15000, 100)
p_atms, T_atms, rho_atms = gd.standard_atmosphere(alts)
thrusts = np.zeros(p_atms.shape)
for i in range(len(p_atms)):
thrusts[i] = spike.calc_ideal_thrust(p_atms[i])
plt.plot(alts, thrusts)
# MOC_mesh = chr_mesh(spike,gamma,0,50,downstream_factor=1.2,plot_chr=1)
def COST_FNC(design_alt, truncate_ratio, T_w, CEA, r_e, alpha, beta, n):
### DESIGNING NOZZLE
(p_atm, T_atm, rho_atm) = gd.standard_atmosphere([design_alt])
PR = CEA.p_c / p_atm
M_e = gd.PR_expansion_mach(PR, CEA.gamma)
expansion_ratio = gd.expansion_ratio(1, M_e, CEA.gamma) #6.64 #8.1273
# print('Exp. ratio: ' + str(expansion_ratio))
# print('PR: ' + str(PR))
A_t = r_e**2 * np.pi / expansion_ratio # max expansion (r_b = 0, r_e**2 >= A_t*expansion_ratio/np.pi)
spike = plug_nozzle(expansion_ratio,
A_t,
r_e,
CEA.gamma,
CEA.T_c,
CEA.p_c,
CEA.a_c,
CEA.rho_c,
n,
truncate_ratio=truncate_ratio)
### CALCULATING COST
## thurst estimation over altitude
alt_range = np.linspace(0, 12000, 30)
(p_atm_r, T_atm_r, rho_atm_r) = gd.standard_atmosphere(alt_range)
#print(CEA.p_c/p_atm_r)
thrust_range = np.zeros(alt_range.shape)
for i in range(alt_range.shape[0]):
if i == 10:
MOC_mesh = MOC.chr_mesh(spike,
gamma,
alt_range[i],
50,
downstream_factor=1.2,
plot_chr=0)
else:
MOC_mesh = MOC.chr_mesh(spike,
gamma,
alt_range[i],
50,
downstream_factor=1.2,
plot_chr=0)
thrust_range[i] = MOC_mesh.compute_thrust('nearest', 10)
work = np.trapz(thrust_range, alt_range)
plt.plot(alt_range, thrust_range, 'o')
plt.show()
## heat transfer required
total_heat_flux = heat_flux(CEA.Pr, CEA.cp, CEA.gamma, CEA.c, CEA.w,
CEA.T_c, T_w, spike)
# print('Work*alpha: ' + str(work*alpha))
# print('Heat flux*beta: ' + str(total_heat_flux*beta))
return -alpha * work + total_heat_flux * beta