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Launcher stages (lower
Typical tank & piping configurations include (see figure below):
Through mechanical deflection of engine or nozzle, the direction of the thrust can be changed. Most launcher stages nowadays use mechanical deflection of (part of) the motor to allow for pitch and yaw control during propelled flight. Roll control is than accomplished by a set of 2-4 non-vectorable motors that thrust in circumferential direction. The next figure shows some ways of mechanical deflection of a liquid rocket engine.
General rocket designs all contain the same elements. A rocket needs some form of propulsion to get it flying through the air. This can be anything from a simple toss of a model rocket by human force, to an engine that uses fuel to propel itself. The propulsion is created by two elements: Oxidizer and Fuel. The oxidizer and fuel tanks are located in different parts of the roket. They are forced through a pump down to the cumbustion chamber where they meet. The oxidizer and fuel ignite creating hot gasses that are squeezed out a nozel at the opposite end creating propulsion for the rocket. The outside of a rocket is very aerodynamic. It can very in length and comes to a point at the top. The top is called the 'nose' of the rocket and is very instrumental in the way the rocket flies.
Here are two different diagrams of rockets:
Turbopumps on rockets
Turbopumps are used on liquid-fuelled rockets to pressurise the fuel and oxidiser before they reach the combustion chamber. What powers the turbopumps (turbochargers on cars use the car exhaust for power, what does a rocket turbopump use)? QuantumEleven 14:56, 17 August 2009 (UTC)
Liquid propellant rocket engines
Liquid propellant rocket engines use a liquid fuel (such as liquid hydrogen or kerosene) and liquid oxidiser (such as liquid oxygen).These are stored in separate tanks and then pumped into the combustion chamber as required. As they are sprayed into the combustion chamber through injection nozzles, they rapidly mix together and react before being ejected.
One advantage of a liquid fuel system is that the amount of thrust can be controlled. This is done by limiting how quickly the fuel is pumped into the combustion chamber.
The three main engines on the tail of the Space Shuttle orbiter are liquid fuel rocket engines. The external tank (ET) is the big orange tank and contains two separate storage tanks one containing liquid hydrogen and one containing liquid oxygen.
The hydrogen and oxygen are pumped to the three main engines. They are sprayed into a combustion chamber where the hydrogen reacts with the oxygen to form gaseous water. It is the high-speed ejection of this gaseous water that produces the thrust.
Each main engine produces a thrust of 1.8 MN (1.8 million N). It does this by reacting 1340 litres of propellant each second and ejecting the gaseous water at a speed of 3560 m/s (12 800 km/h).
CHEMICAL ROCKET LAUNCHER
Gas heated by a chemical reaction provides thrust. Cargo transported by rockets is called payload. The ratio of cargo mass to the total mass of the rocket including its cargo and propellant is called payload fraction. Its value ranges from 6 percent for liquid propellant rockets to 0.2 percent for solid propellant rockets. The minimum mass is 10 tons.
If we ignore gravity and aerodynamic drag, the final velocity of a rocket equals:
V = (exhaust_gas_velocity) natural_logarithm (cargo_mass / total_mass)
The total_mass includes structural parts, propellant, and cargo. According to the above formula, which is know as the rocket equation, a high velocity of exhaust gas is needed to launch massive cargo. Rocketeers often talk of specific impulse, which is measured in seconds and is proportional to the exhaust gas velocity. A specific impulse of one second corresponds with the exhaust gas velocity of 9.8 m/s. The maximum velocity of the exhaust gas is about twice its speed of sound:
Umax = A0(2/(G-1))0.5
The high exhaust gas velocity calls for a hot gas having low molecular mass. The extreme temperature of the exhaust gas is the main cause of the high cost and high failure rate of rocket launchers. To maximize the specific impulse, some researchers attempt to build rockets propelled by pure hydrogen heated either by electric current, or a laser, or microwaves, or a nuclear reactor.
There are five types of chemical rockets:
Okay guy's, I am back and this time it's going to be the rocket engine just like I had mentioned in my previous post. Okay, so a rocket engine huh? It must be freaking you out because it's supposed to be one of the most complex pieces of engineering made by mankind. We'll its complex no doubt, but am going to make it super simple(I did my best guy's)! In very simple words a rocket engine is a jet engine who's complexity is ten folds, so I think going through the description of the jet engine would probably give you a basic idea about a\what a rocket engine is.
1) Description: A rocket engine is very similar to the jet engine and works on the same principle, but yet is very different. A rocket engine is capable of producing thrust which is almost equivalent to the thrust produced by 50 jumbo jets, yes it's that powerful. It uses cryogenic liquid
hydrogen as fuel(which is one of the coldest liquids present) and liquid oxygen as the oxidizer.
Although these liquids are one of the coldest liquids around, when they combine in the
combustion chamber they go through an intense reaction which produces temperatures of
above 3330 C. The fuel and the oxidizer are known as the propellants and they form a high
speed propulsive jet. The rocket engine basically works by throwing stuff out of the back(In
this case propellant mass), literally. The rocket engine is divided into 7 main parts:
a) Oxidizer system
b) Fuel system
d) Main combustion chamber
g) Helium system
These components form a part of the Space shuttle main engine(SSME). Now I will be
explaining to you the different components in the easiest way possible. This might get a little
boring, so you can jump right into it's working if you find this uninteresting.
a) Oxidizer system: The oxidizer system consists of a Low pressure oxidizer turbopump
(LPOT) and a high pressure oxidizer turbopump(HPOT). Don't worry,
these are just fancy terms, there basic function is to increase the pressure
of the oxygen which is the oxidizer. High pressures, allow the high
pressure oxidizer turbines to operate without cavitating(cavitating is
basically the formation of liquid free zones).
b) Fuel system: The fuel system consists of a low pressure hydrogen turbopump(LPHTP)
and a high pressure hydrogen turbopump(HPHTP). The increase in pressure
of hydrogen by the LPHTP permits the HPHTP to operate at high speeds
without cavitating. The hydrogen from the HTHTP is seperated and directed
into three pathways. The first pathway of hydrogen is towards the walls of the
combustion chamber to cool it down. the second flow is directed towards
low pressure fuel turbopump in the combustion chamber to turn its
turbines. The first flow is directed to the liquid hydrogen tank to maintain
pressure. Another part of this flow(Not included in the above three) is a
combined flow of the oxidizer and fuel towards the preburner.
c) Preburners: Here the fuel and oxidizer are mixed for efficient combustion. There are
fuel injectors passing out fuel at whose mouth a spark plug is present the
ignite the mixture. The spark plug is kept on for a few seconds until this
process of ignition becomes self sustaining. Its main function is to provide fuel-
rich gases for the turbines to generate power to operate the high pressure
d) Combustion chamber: The combustion chamber receives fuel-rich hot gases. The
gaseous fuel enters the combustion chamber through the fuel
injector which mixes the propellants(hydrogen and oxygen).
A spark plug ignites the mixture here as well, and is kept on for
about three seconds till this procedure becomes self sustaining.
The shell of the combustion chamber is made of copper-silver-
zirconium alloy to withstand the extreme tempertures of 3,315°C
which is higher than the boiling point of iron.
e) Nozzle: The nozzle is the part of the main engine, through which the exhaust gases shoot out.
The rim of the nozzle is angled and due to this the pressure of the gases increase at
rim of the nozzle just before it leaves the rocket increasing the force at which the
gases shoot out. The walls of the nozzle is lined with brazed stainless steel cooling
passages through which liquid hydrogen is passes which acts as a coolant.
f) Controller: Each engine is equipped with a main engine controller which controls all functions
of the engine. The controllers are designed to be tough enough to withstand the
force of launch and are extremely resilient to damage.
g) Helium system: The main engine controller operates five main propellant valves which can be
fully closed by using the engine's helium system as a back-up in case of an
2) Working: The working of a rocket engine is a very similar to the working of jet engine. The rocket uses
propellant mass to produce a high speed propulsive jet. The liquid hydrogen and liquid oxygen is turned gas
and is passed on into the combustion chamber. The fuel(hydrogen) is mixed with the oxidizer
(oxygen) through the fuel injectors. The mixture of hydrogen and oxygen is ignited using a spark
plug producing high temperatures(3,315 °C). This burning hot propulsive gas turns the turbines which
in turn generates power for operating the high pressure turbopumps. The gas them passes on to the
nozzle which further increases its pressure releasing the propulsive jet with tremendous force producing
very high amounts of thrust(1,890 kN) pushing the rocket upwards.
*The rocket engine is a type of jet engine.
3) Uses: a) Rocket engines are used during space shuttle lift-off's for producing extreme amounts of thrust.
b) Rocket engined are used in space exploration shuttles.
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