Jet Propulsion System
It is the propulsion of a jet aircraft (or) Rocket engines which do not use atmospheric air other missiles by the reaction of jet coming out with high velocity. The jet propulsion in used when the oxygen is obtained from the surrounding atmosphere.
Jet propulsion is based on Newton’s second and third low of motion. Newton’s second law states that ‘the range of momentum in any direction is proportional to the force acting in that direction’. Newton’s third low states that for every action there is an equal and opposite reaction.
In propulsion momentum is imparted to a mass of fluid in such a manner that the reaction of the imparted momentum furnishes a propulsive force. The jet aircraft draws in air and expels it to the rear at a markedly increased velocity; the rocket greatly changes the velocity of its fuel which it ejects rearward in the form of products of combustion. In each case the action of accelerating the mass of fluid in a given direction created a reaction in the opposite direction in the form of a propulsive
force. The magnitude of this propulsive force is defined as thrust.
The jet propulsion engines are classified basically as to their method of operation. The two main categories of jet propulsion engines are the atmospheric jet engines and the rockets. The atmospheric jet engines require oxygen from the atmospheric air for the combustion of fuel. As a result, their performance depends to a great degree on the forward speed of the engine and upon the atmospheric pressure and temperature.