proptools.isentropic module

Isentropic relations.

See Isentropic Relations for a physical explaination of the isentropic relations.

stag_temperature_ratio(M, gamma) Stagnation temperature / static temperature ratio.
stag_pressure_ratio(M, gamma) Stagnation pressure / static pressure ratio.
stag_density_ratio(M, gamma) Stagnation density / static density ratio.
velocity(v_1, p_1, T_1, p_2, gamma, m_molar) Velocity relation between two points in an isentropic flow.
proptools.isentropic.stag_density_ratio(M, gamma)

Stagnation density / static density ratio.

Parameters:
  • M (scalar) – Mach number [units: dimensionless].
  • gamma (scalar) – Heat capacity ratio [units: dimensionless].
Returns:

the stagnation density ratio \(\rho_0 / \rho\) [units: dimensionless].
Return type:

scalar
proptools.isentropic.stag_pressure_ratio(M, gamma)

Stagnation pressure / static pressure ratio.

Parameters:
  • M (scalar) – Mach number [units: dimensionless].
  • gamma (scalar) – Heat capacity ratio [units: dimensionless].
Returns:

the stagnation pressure ratio \(p_0 / p\) [units: dimensionless].
Return type:

scalar
proptools.isentropic.stag_temperature_ratio(M, gamma)

Stagnation temperature / static temperature ratio.

Parameters:
  • M (scalar) – Mach number [units: dimensionless].
  • gamma (scalar) – Heat capacity ratio [units: dimensionless].
Returns:

the stagnation temperature ratio \(T_0 / T\) [units: dimensionless].
Return type:

scalar
proptools.isentropic.velocity(v_1, p_1, T_1, p_2, gamma, m_molar)

Velocity relation between two points in an isentropic flow.

Given the velocity, pressure, and temperature at station 1 and the pressure at station 2, find the velocity at station 2. See Rocket Propulsion Elements, 8th edition, equation 3-15b.

Parameters:
  • v_1 (scalar) – Velocity at station 1 [units: meter second**-1].
  • p_1 (scalar) – Pressure at station 1 [units: pascal].
  • T_1 (scalar) – Temperature at station 1 [units kelvin].
  • p_2 (scalar) – Pressure at station 2 [units: pascal].
  • gamma (scalar) – Gas ratio of specific heats [units: dimensionless].
  • m_molar (scalar) – Gas mean molar mass [units: kilogram mole**-1].
Returns:

velocity at station 2 [units: meter second**-1].
Return type:

scalar