def __cost_end_func(self,
no_alt_range_int,
spike,
CEA,
downstream_factor=1.2,
chr_mesh_n=120,
no_core=1):
alt_range = np.linspace(0, 9144, no_alt_range_int)
# shuffle arrays so each core computes similar complexity on average
np.random.shuffle(alt_range)
(p_atm_r, T_atm_r, rho_atm_r) = gd.standard_atmosphere(alt_range)
thrust_range = self.__multicore_thrust_compute(spike,
alt_range,
CEA.gamma,
downstream_factor=1.2,
chr_mesh_n=chr_mesh_n,
no_core=no_core)
# unshuffle arrays
ordered_idx = np.argsort(alt_range)
alt_range = alt_range[ordered_idx]
thrust_range = thrust_range[ordered_idx]
work = np.trapz(thrust_range, alt_range)
# plt.plot(alt_range,thrust_range,'o')
# plt.show()
print('work = ' + str(work))
## heat transfer required
total_heat_flux = heat_flux(CEA.Pr, CEA.cp, CEA.gamma, CEA.c, CEA.w,
CEA.T_c, T_w, spike)
return (work, total_heat_flux)
def cost_func_contour_params(params,
spike,
T_w,
CEA,
alpha,
beta,
chr_mesh_n=145,
no_core=4):
params = np.asarray(params)
if len(params.shape) > 1:
raise ValueError('Input params not correct shape. Should be 1D array')
x_vals, y_vals = np.split(params, 2)
spike.x = x_vals
spike.y = y_vals
## thurst estimation over altitude
alt_range = np.linspace(0, 9144, 3 * no_core)
# shuffle arrays so each core computes similar complexity on average
np.random.shuffle(alt_range)
(p_atm_r, T_atm_r, rho_atm_r) = gd.standard_atmosphere(alt_range)
thrust_range = multicore_thrust_compute(spike,
alt_range,
CEA.gamma,
downstream_factor=1.2,
chr_mesh_n=chr_mesh_n,
no_core=no_core)
# unshuffle arrays
ordered_idx = np.argsort(alt_range)
alt_range = alt_range[ordered_idx]
thrust_range = thrust_range[ordered_idx]
work = np.trapz(alt_range, thrust_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)
return -alpha * work + beta * total_heat_flux
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