def test_huzel_43_a1_throat(self):
"""Test against Huzel and Huang example problem 4-3, for the A-1 engine
at the throat."""
# Values given in the problem statement
p_c = 6.9e6 # 1000 psi
c_star = 1725. # 5660 ft second**-1
D_t = 0.633 # 24.9 inch
c_p = 2031. # 0.485 BTU lbm**-1 rankine**-1
mu_e = 7.47e-5 # 4.18e-6 lbm inch**-1 second**-1
Pr = 0.816 # Prandtl number
sigma = 1.0 # Correction factor
# Answer given for the convection coefficient
h_g_huzel = 7950. # 0.0027 BTU inch**-2 second**-1 fahrenheit**-1
h_g = convection.bartz(p_c, c_star, D_t, D_t, c_p, mu_e, Pr, sigma)
self.assertTrue(abs(h_g - h_g_huzel) < 1e3)
def test_huzel_43_a1_throat(self):
"""Test against Huzel and Huang example problem 4-3, for the A-1 engine
at the throat."""
# Values given in the problem statement
p_c = 6.9e6 # 1000 psi
c_star = 1725. # 5660 ft second**-1
D_t = 0.633 # 24.9 inch
c_p = 2031. # 0.485 BTU lbm**-1 rankine**-1
mu_e = 7.47e-5 # 4.18e-6 lbm inch**-1 second**-1
Pr = 0.816 # Prandtl number
sigma = 1.0 # Correction factor
# Answer given for the convection coefficient
h_g_huzel = 7950. # 0.0027 BTU inch**-2 second**-1 fahrenheit**-1
h_g = convection.bartz(p_c, c_star, D_t, D_t, c_p, mu_e, Pr, sigma)
self.assertTrue(abs(h_g - h_g_huzel) < 1e3)
def test_ssme(self):
"""Test agaisnt the SSME example from 16.512 Lecture 7."""
T_e = 3200.
T_w = 1000.
T_avg = (T_e + T_w) / 2
sigma = convection.bartz_sigma_sanchez(T_e, T_avg)
p_c = 22e6
c_star = 2600.
c_p = 2800.
mu_e = 3e-5
Pr = 1
D_t = 0.25 # Not given in example, taken from another reference.
# Note: the value for h_g given in the lecture notes, 160e3 W m**-2 K**-1
# appears to be incorrect. Kelly Mathesius and Matt Vernacchia re-did
# the calculation, and instead got 22e3 W m**-2 K**-1.
h_g_exp = 22e3 # Answer from the example
h_g = convection.bartz(p_c, c_star, D_t, D_t, c_p, mu_e, Pr, sigma)
self.assertTrue(abs(h_g - h_g_exp) < 0.1e3)
def test_ssme(self):
"""Test agaisnt the SSME example from 16.512 Lecture 7."""
T_e = 3200.
T_w = 1000.
T_avg = (T_e + T_w) / 2
sigma = convection.bartz_sigma_sanchez(T_e, T_avg)
p_c = 22e6
c_star = 2600.
c_p = 2800.
mu_e = 3e-5
Pr = 1
D_t = 0.25 # Not given in example, taken from another reference.
# Note: the value for h_g given in the lecture notes, 160e3 W m**-2 K**-1
# appears to be incorrect. Kelly Mathesius and Matt Vernacchia re-did
# the calculation, and instead got 22e3 W m**-2 K**-1.
h_g_exp = 22e3 # Answer from the example
h_g = convection.bartz(p_c, c_star, D_t, D_t, c_p, mu_e, Pr, sigma)
self.assertTrue(abs(h_g - h_g_exp) < 0.1e3)