Velocity of Exhaust Gases At The Nozzle For a Rocket Engine Using Specific Impulse Calculator

The velocity of the exhaust gases at the nozzle exit for a rocket engine is a critical parameter that determines the speed of the expelled gases and, consequently, the thrust generated by the engine.

The rocket equation is an idealized representation and neglects factors like air resistance, pressure variations, and temperature effects.

The formula for calculating the nozzle exhaust air velocity using the rocket equation is:

Where:

• V_exit is the change in velocity of the rocket (in meters per second, m/s).
• I_sp​ is the specific impulse of the rocket engine (in seconds, s).
• g₀ ​ is the acceleration due to gravity at the Earth’s surface (approximately 9.81 m/s²).
• m₀​ is the initial mass of the rocket (including propellant, air and structure, in kilograms, kg).
• m_f ​ is the final mass of the rocket (after propellant burnout, in kilograms, kg).