How does a rocket engine works !?

 What is the difference between a jet airplane engine and a rocket? November 2002 In our September column, we explained how a rocket works in space where there's no air. People generally believe that a rocket must press on air so as to propel the rocket forward, but that's not the case. Briefly stated, a rocket works because of Newton’s third law, which says for every action there is an equal, and opposite reaction. The burning of fuel creates gases at high , which exit from the exhaust nozzle and push the rocket forward. As gases exit the rocket, a reaction force (thrust) pushes on the rocket making it proceed . The faster the gases are expelled from the rocket, the greater the thrust. Think of how a hose creates a force pushing back on the hose as water squirts from it. In fact, jet engines and rockets operate an equivalent general physics principle. Both eject fuel out the back. The momentum imparted to the present exhaust is adequate to the momentum gained by the vehicle, thus making the vehicle proceed . One difference between rockets and jets is found in the type of fuel they burn. Jet engines are air breathers. They absorb air (which contains oxygen needed for combustion), mix it with fuel, burn it to extend the pressure, and exhaust the spent gases out the rear at a high rate of speed. This high-speed ejection of mass propels the plane forward. Rockets do almost an equivalent thing with two exceptions. Unlike jets, they carry their own oxygen along side them and a rocket doesn't have wings that add lift. On the spacecraft , you notice an orange tank, which actually contains separate tanks of hydrogen and oxygen. These two ingredients are mixed within the liquid-fuel rocket , burned, and expelled out the nozzle. The white, solid-fuel rocket on all sides contains a chemical mixture during which the oxidant is a component of the fuel. Rocket fuel can burn without external oxygen being present. As a side note, once a solid fuel rocket is ignited, it can't be turned off. Jet engines must have outside oxygen from the air. Another difference is that jet planes have wings for lift and rockets don't . The density of air and therefore the speed of the plane affect the lift on the wings. For rockets the lift (thrust) is provided solely by the expelled gases. Therefore, a rocket can travel within the vacuum of space barren of air, but a reaction-propulsion engine couldn't . A jet features a ceiling limit above which it cannot fly because there's not enough air. The reaction-propulsion engine must be ready to ’breathe’ so as to function. Rocket fuel is considerably more efficient than jet fuel and rockets usually are more powerful. However, the rocket generally is heavier because it must carry all of its oxidizer with it. Science Guys The Science Guys thank the Jackson Sun for permission to reprint these archived Inquiring Minds columns online! The Jackson Sun chose to discontinue monthly articles in 2005 and now they only appear as requested. List of Articles « Physics Home The Science Guys were: Kyle Hathcox Glenn Marsch David Ward

Source : en.wikipedia.org

What is the difference during a jet airplane engine and a rocket? November 2002 In our September column, we explained how a rocket works in space where there's no air. People generally believe that a rocket must press on air so as to propel the rocket forward, but that's not the case. Briefly stated, a rocket works because of Newton’s third law, which says for every action there is an equal, and opposite reaction. The burning of fuel creates gases at high , which exit from the exhaust nozzle and push the rocket forward. As gases exit the rocket, a reaction force (thrust) pushes on the rocket making it proceed . The faster the gases are expelled from the rocket, the greater the thrust. Think of how a hose creates a force pushing back on the hose as water squirts from it. In fact, jet engines and rockets operate an equivalent general physics principle. Both ejectfuel out the back. The momentum imparted to the present exhaust is adequate to the momentum gained by the vehicle, thus making the vehicle proceed . One difference between rockets and jets is found in the type of fuel they burn. Jet engines are air breathers. They absorb air (which contains oxygen needed for combustion), mix it with fuel, burn it to extend the pressure, and exhaust the spent gases out the rear at a high rate of speed. This high-speed ejection of mass propels the plane forward. Rockets do almost an equivalent thing with two exceptions. Unlike jets, they carry their own oxygen along side them and a rocket doesn't have wings that add lift. On the spacecraft , you notice an orange tank, which actually contains separate tanks of hydrogen and oxygen. These two ingredients are mixed within the liquid-fuel rocket , burned, and expelled out the nozzle. The white, solid-fuel rocket on all sides contains a chemical mixture during which the oxidant is a component of the fuel. Rocket fuel can burn without external oxygen being present. As a side note, once a solid fuel rocket is ignited, it can't be turned off. Jet engines must have outside oxygen from the air. Another difference is that jet planes have wings for lift and rockets don't . The density of air and therefore the speed of the plane affect the lift on the wings. Forrockets the lift (thrust) is provided solely by the expelled gases. Therefore, a rocket can travel within the vacuum of space barren of air, but a reaction-propulsion engine couldn't . A jet features a ceiling limit above which it cannot fly because there's not enough air. The reaction-propulsion engine must be ready to ’breathe’ so as to function.