explain me about rocket thrust engine.?

Question

about their basics,principle,working,advantage,diaadvantage,features,characteristic,etc

Answer 1

Basic idea is to throw mass backwards to generate thrust (one of Newton's laws of motion). This is mostly achieved by burning liquids or solids with an oxidizer - the resultant hot gases are directed through a nozzle. It is the velocity of the gas that generates the force, as mass per volume is low. Newer engines ionize a gas and expel this - very low thrust, but last a long time, so eventually get up to speed.

Answer 2

Basic principle: Newton's third law, "for every action there is equal and opposite reaction"
Working: Hot combustion gas from engine expands through nozzle, exerts equal but opposite thrust to propel the rocket.
Advantage: Direct launch, no need of run-way, efficient way to launch rocket.

Answer 3

yhere are two type of engines in a rocket

solid fuel
liquid fuel.

Answer 4

CZAR-ROCKET

Thrust and Solid-fuel Rockets
The "strength" of a rocket engine is called its thrust. Thrust is measured in "pounds of thrust" in the U.S. and in Newtons under the metric system (4.45 Newtons of thrust equals 1 pound of thrust). A pound of thrust is the amount of thrust it would take to keep a 1-pound object stationary against the force of gravity on Earth. So on Earth, the acceleration of gravity is 32 feet per second per second (21 mph per second). If you were floating in space with a bag of baseballs and you threw one baseball per second away from you at 21 mph, your baseballs would be generating the equivalent of 1 pound of thrust. If you were to throw the baseballs instead at 42 mph, then you would be generating 2 pounds of thrust. If you throw them at 2,100 mph (perhaps by shooting them out of some sort of baseball gun), then you are generating 100 pounds of thrust, and so on.
One of the funny problems rockets have is that the objects that the engine wants to throw actually weigh something, and the rocket has to carry that weight around. So let's say that you want to generate 100 pounds of thrust for an hour by throwing one baseball every second at a speed of 2,100 mph. That means that you have to start with 3,600 one pound baseballs (there are 3,600 seconds in an hour), or 3,600 pounds of baseballs. Since you only weigh 100 pounds in your spacesuit, you can see that the weight of your "fuel" dwarfs the weight of the payload (you). In fact, the fuel weights 36 times more than the payload. And that is very common. That is why you have to have a huge rocket to get a tiny person into space right now -- you have to carry a lot of fuel.

Space Shuttle

You can see the weight equation very clearly on the Space Shuttle. If you have ever seen the Space Shuttle launch, you know that there are three parts:

The Orbiter
The big external tank
The two solid rocket boosters (SRBs)
The Orbiter weighs 165,000 pounds empty. The external tank weighs 78,100 pounds empty. The two solid rocket boosters weigh 185,000 pounds empty each. But then you have to load in the fuel. Each SRB holds 1.1 million pounds of fuel. The external tank holds 143,000 gallons of liquid oxygen (1,359,000 pounds) and 383,000 gallons of liquid hydrogen (226,000 pounds). The whole vehicle -- shuttle, external tank, solid rocket booster casings and all the fuel -- has a total weight of 4.4 million pounds at launch. 4.4 million pounds to get 165,000 pounds in orbit is a pretty big difference! To be fair, the orbiter can also carry a 65,000 pound payload (up to 15 x 60 feet in size), but it is still a big difference. The fuel weighs almost 20 times more than the Orbiter.
[Reference: The Space Shuttle Operator's Manual]

All of that fuel is being thrown out the back of the Space Shuttle at a speed of perhaps 6,000 mph (typical rocket exhaust velocities for chemical rockets range between 5,000 and 10,000 mph). The SRBs burn for about two minutes and generate about 3.3 million pounds of thrust each at launch (2.65 million pounds average over the burn). The three main engines (which use the fuel in the external tank) burn for about eight minutes, generating 375,000 pounds of thrust each during the burn.

Solid-fuel Rockets: Fuel Mixture
Solid-fuel rocket engines were the first engines created by man. They were invented hundreds of years ago in China and have been used widely since then. The line about "the rocket's red glare" in the National Anthem (written in the early 1800's) is talking about small military solid-fuel rockets used to deliver bombs or incendiary devices. So you can see that rockets have been in use quite awhile.

The idea behind a simple solid-fuel rocket is straightforward. What you want to do is create something that burns very quickly but does not explode. As you are probably aware, gunpowder explodes. Gunpowder is made up 75% nitrate, 15% carbon and 10% sulfur. In a rocket engine you don't want an explosion -- you would like the power released more evenly over a period of time. Therefore you might change the mix to 72% nitrate, 24% carbon and 4% sulfur. In this case, instead of gunpowder, you get a simple rocket fuel. This sort of mix will burn very rapidly, but it does not explode if loaded properly. Here's a typical cross section:


A solid-fuel rocket immediately before and after ignition


On the left you see the rocket before ignition. The solid fuel is shown in green. It is cylindrical, with a tube drilled down the middle. When you light the fuel, it burns along the wall of the tube. As it burns, it burns outward toward the casing until all the fuel has burned. In a small model rocket engine or in a tiny bottle rocket the burn might last a second or less. In a Space Shuttle SRB containing over a million pounds of fuel, the burn lasts about two minutes.

Solid-Fuel Rockets: Channel Configuration
When you read about advanced solid-fuel rockets like the Shuttle's solid rocket boosters, you often read things like:

The propellant mixture in each SRB motor consists of an ammonium perchlorate (oxidizer, 69.6 percent by weight), aluminum (fuel, 16 percent), iron oxide (a catalyst, 0.4 percent), a polymer (a binder that holds the mixture together, 12.04 percent), and an epoxy curing agent (1.96 percent). The propellant is an 11-point star-shaped perforation in the forward motor segment and a double- truncated- cone perforation in each of the aft segments and aft closure. This configuration provides high thrust at ignition and then reduces the thrust by approximately a third 50 seconds after lift-off to prevent overstressing the vehicle during maximum dynamic pressure.
This paragraph discusses not only the fuel mixture but also the configuration of the channel drilled in the center of the fuel. An "11-point star-shaped perforation" might look like this:



The idea is to increase the surface area of the channel, thereby increasing the burn area and therefore the thrust. As the fuel burns the shape evens out into a circle. In the case of the SRBs, it gives the engine high initial thrust and lower thrust in the middle of the flight.

Solid-fuel rocket engines have three important advantages:

Simplicity
Low cost
Safety

Answer 5

they are propulsed by retiliatory force using special fuel