To the casual observer, looking at a gas turbine engine and seeing very little evidence of moving parts let alone the visible means of drive, one could be excused of the thought ‘How does it work?’ In order to understand the working mechanism of the jet engine, it is important to take note of and understand the basic principles and laws behind it.
The jet engine works on very basic principles. In my explanation, I will try to be as simple as possible. The word jet implies the existence of a fluid. Thus, the jet engine uses a fluid (air) to produce forward motion (thrust). The study of masses and gases was vital for the breakthrough and success of the jet engine. The scientist behind all this study was Sir Isaac Newton. His laws- Newton’s first, second and third law- are the helpful laws in understanding how the jet engine works.
The jet engine has fans which cause the air in front of it to be sucked into the intake and are accelerated backwards towards the exhaust. Newton’s second law states: the force acting on a body is proportional to the mass times the acceleration. This law can be summarized by the formula F=ma. Looking at the jet engine, we realize that the air it is accelerating (a) has a mass (m). This means that a force is being created. However, since the fan is sucking the air, it means that the force is acting backwards!
Before you ask yourself too many questions or wonder why it creates a force in the wrong direction, I would like to assure you that it is deliberate. Why? How will it generate forward motion? These questions are answered by Newton’s third law which states: for every action, there is an equal and opposite reaction. Yes, the action of the backward force by the air creates an equal reaction (force) in the forward direction.
With that understanding, there is no need of describing the parts of a jet engine because it may be technical for most people. The basic parts of a jet engine are the intake, compressors, combustion chamber, turbine and the exhaust duct. The main goal is to accelerate the air at the exhaust to generate forward thrust.
To achieve this, air is sucked at the intake and guided to compressor where its pressure is increased. The high pressure gas is mixed with fuel and burnt to increase the amount of energy in the gas. The process occurs in the combustion chamber. High energy air is guided to the turbine where it loses some of its energy to the turbine, which uses this energy to generate electricity for aircraft usage. The air then leaves the engine through a specially designed exhaust duct which ensures it accelerates at the highest rate possible. The acceleration in turn pushes the engine forward.
The jet engine is lightweight in construction, but generates immense power that is really puzzling. I hope I have played a role in trying to solve the puzzle for you.
