What affects specific impulse?

Thrust is the force supplied by the engine and depends on the amount of reaction mass flowing through the engine. Specific impulse measures the impulse produced per unit of propellant and is proportional to the exhaust velocity.

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 fuel has the highest specific impulse?

liquid hydrogen
In combination with an oxidizer such as liquid oxygen, liquid hydrogen yields the highest specific impulse, or efficiency in relation to the amount of propellant consumed, of any known rocket propellant.

Do rocket engines have constant specific impulse?

Two different rocket engines have different values of specific impulse. The engine with the higher value of specific impulse is more efficient because it produces more thrust for the same amount of propellant.

Which one of the following engines is expected to have the maximum specific impulse?

5. Which of the following engines can achieve the maximum specific impulse of 5000 s? Explanation: Ion-electrostatic engine has a specific impulse of 1200-5000 s. Nuclear fission type engines have Isp of 500-860 s, while solar heating engines have it around 400-700 s.

Why does rocket thrust increase with altitude?

term represents the pressure thrust term. At full throttle, the net thrust of a rocket motor improves slightly with increasing altitude, because as atmospheric pressure decreases with altitude, the pressure thrust term increases.

What determines how much thrust is generated in a solid fuel rocket engine at any given time?

The amount of thrust produced by the rocket depends on the mass flow rate through the engine, the exit velocity of the exhaust, and the pressure at the nozzle exit.

Why is specific impulse important?

The engine with the higher value of specific impulse is more efficient because it produces more thrust for the same amount of propellant. Dividing the thrust required by the specific impulse will tell us how much weight flow of propellants our engine must produce.

Which of the following can typically achieve maximum effective exhaust velocity?

Which of the following can typically achieve maximum effective exhaust velocity? Explanation: Electrostatic and electromagnetic type of propulsion system can achieve the maximum exhaust velocity out of the given options. It is typically of the order of 20,000 m/s.

What is the meaning of calorific value of fuels?

Meaning of Calorific Value of Fuels: The calorific value or the heat value of a solid, liquid or gaseous fuel is defined as the number of heat units developed by the complete combustion of unit mass or unit normal volume of a given fuel. It may be expressed as kJ/kg or kJ/normal m 3.

What is the calorific intensity of combustion?

In combustion work the term calorific intensity is used which means the maximum temperature attained in a given combustion. For gaseous fuels the calorific value is expressed as kJ/m 3 measured at STP. Any fuel containing available hydrogen will form water vapour during the process of combustion.

What happens to the calorific value when volume increases?

If there is an increase in volume then some energy will be used up in performing the work of expansion. In this case the calorific value will be decreased. If there is no change of volume, the calorific value of the fuel remains unchanged.

Why don’t all fuels release the same amount of energy upon combustion?

Now, the energy produced by burning paper is not sufficient to run cars but energy produced by burning petrol is enough to do so. Thus, we can say that each fuel releases its own set of energy i.e. all of them do not release the same amount of energy upon combustion.