def test_simple_input(self):
# Expected exit velocity and mass flow
# Should be sonic throat too, due to vacuum at exit
u_exit_expected = 1.0801234497346432
m_dot_expected = 0.6847314563772704 # Should be equal to Gamma(1.4) (vandankerkhove function)
p_exit = 0.5282817877171743 # Should be exit pressure for M=1
AR_exit = 1
T_chamber = 1
R = 1
gamma = 1.4
p_chamber = 1
A_throat = 1
AR_exit = 1
p_back = 0
# Expected thrust
F_expected = m_dot_expected * u_exit_expected + p_exit * A_throat * AR_exit
res = IRT.thrust(p_chamber=p_chamber,
T_chamber=T_chamber,
A_throat=A_throat,
AR_exit=AR_exit,
p_back=p_back,
gamma=gamma,
R=R)
self.assertEqual(res, F_expected)
def test_TRP_example(self):
# Slide 57-51 from Ideal Rocket Motor lecture from Thermal Rocket Propulsion course are used as example (Zandbergen)
expected = 401.8e3
gamma = 1.3
R = 390.4
p_chamber = 5.6e6
p_back = 6.03e3
T_chamber = 3400
AR_exit = 49
d_exit = 1.6
A_exit = 0.25 * math.pi * d_exit**2
A_throat = A_exit / AR_exit
res = IRT.thrust(p_chamber=p_chamber,
T_chamber=T_chamber,
A_throat=A_throat,
AR_exit=AR_exit,
p_back=p_back,
gamma=gamma,
R=R)
self.assertAlmostEqual(
expected, res,
-3) # Slight rounding error again and 1 digit accuracy less
