Table of Contents
What is the specific impulse of a rocket?
Definition of specific impulse : the thrust produced per unit rate of consumption of the propellant that is usually expressed in pounds of thrust per pound of propellant used per second and that is a measure of the efficiency of a rocket engine.
What is the total impulse for a rocket engine?
Total impulse is the product of thrust times duration over the motor burn time, and is measured in Newton-seconds (Ns). This measures the total amount of momentum imparted to the rocket by the motor.
What is impulse rate?
In classical mechanics, impulse (symbolized by J or Imp) is the integral of a force, F, over the time interval, t, for which it acts. The SI unit of impulse is the newton second (N⋅s), and the dimensionally equivalent unit of momentum is the kilogram meter per second (kg⋅m/s).
What does the total impulse represent?
noun Rocketry. a measure of the maximum momentum that a given reaction engine and fuel supply can impart to a vehicle.
What is impulse bit?
Definition. The impulse imparted to a spacecraft by a single firing of a thruster; the minimum impulse bit reflects the level of precision associated with the propulsion system.
Which of the rocket propulsion below has the highest specific impulse?
Chemical propulsion is unrivalled for thrust, and top out at around 450-460s for LH2/LOX.
The specific impulse of a rocket propellant is a rough measure of how fast the propellant is ejected out of the back of the rocket. A rocket with a high specific impulse doesn’t need as much fuel as a rocket with low specific impulse. The higher the specific impulse, the more push you get for the fuel that rushes out.
What is the specific impulse of a jet engine?
An air-breathing engine typically has a much larger specific impulse than a rocket: a jet engine may have a specific impulse of 2000–3000 seconds or more at sea level. In some ways, comparing specific impulse seems unfair in the case of jet engines and rockets.
What is the mass flow rate of a rocket?
Remember that mdot is the mass flow rate; it is the amount of exhaust mass per time that comes out of the rocket. Assuming the equivalent velocity remains constant with time, we can integrate the equation to get: I = m * Veq where m is the total mass of the propellant.
What is the effective exhaust velocity of an air-breathing rocket?
Hence effective exhaust velocity is not physically meaningful for air-breathing engines; nevertheless, it is useful for comparison with other types of engines. The highest specific impulse for a chemical propellant ever test-fired in a rocket engine was 542 seconds (5.32 km/s) with a tripropellant of lithium, fluorine, and hydrogen.