Time Travel Research Center © 2005 Cetin BAL - GSM:+90  05366063183 - Turkey / Denizli 

Launcher stages (lower stages)
A typical internal equipment complement for a launcher stage is shown in the view of the Ariane 5 first stage. This stage is a crogenic propellant rocket stage using liquid oxygen and liquid hydrogen as the chemical propellants. It essentially consists of two tanks mounted on top of each other (tandem tank arrangement) with a common bulkhead (lower bulkhead of oxygen tank serves as upper bulkhead of hydrogen tank), piping (both external and internal), the thrust generation system (vulcain engine), a pump-fed feed system supported to some extent by Helium tank pressurization. 

Ariane 5 first stage

Typical tank & piping configurations include (see figure below):
 

  • Tandem tanks (with external piping)
     
  • Tandem tanks with common bulkhead (with internal piping)
     
  • Concentric tanks
  • Parallel tanks
     

Typical tank arrangements launcher stages

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.

 


The Ariane 5 EPS L 9.7 stage propulsion system, see fig. below, has a total stage mass of 11 tons (t) of which 9,7 t. propellant (3,2 t. MMH fuel and 6,5 t. NTO oxidizer). Its dimensions are height 3,56 m and diameter 3,94 m. EPS dry mass is 1,15 t.  The main propulsion system consists of a single 27,5 kN Aestus engine (110 kg dry mass), 4 cylindrical (close to spherical) propellant tanks of diameter 1,410 m (length of cylindrical section is 0,4 D), and 2 He pressurant tanks (0,3 m3 @ 400 bar). The EPS attitude control system (SCA, Système de Contrôle d'Attitude) is designed to provide for spin stabilization. It consists of two spherical tanks containing 35 liter each, feeding six hydrazine thrusters to deliver a thrust of 400 N each. Of these 6 thrusters two are used for spin-up and two for spin-down. The remaining two are to allow tilting the spin axis.
 

Rocket Diagram

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)


The turbopumps are powered by a preburner, which burns a small amount of fuel and oxidizer to run the turbopumps. In the picutre, the preburner is number 6. The preburner provides hot gas to run the turbine (number 5), which drives the turbopumps (numbers 3 and 4). anonymous6494 15:25, 17 August 2009 (UTC)


(ec) There's a fairly extensive discussion in this page linked from our article. For cryogenic fuels and oxidizers (liquid oxygen, liquid hydrogen), some pumps can be driven simply by heating the liquid to ambient temperature or above and allowing the expanding gas produced to drive the turbine. With other fuels, a preburner can be used which combines fuel and oxidizer to generate a small amount of hot, pressurized gas. There are several variations on these themes, which offer different methods of preheating the fuels, and which vent the turbine exhaust in different ways. TenOfAllTrades(talk) 15:27, 17 August 2009 (UTC)


It depends on the design. Sometimes, the turbos are powered by a totally separate source (e.g. a battery or a small separate combustion engine). Other times, they tap off the main propulsion energy source, or use the decompression of a refrigerated fluid to power the pump. All of these scenarios have various advantages and disadvantages to the stability, robustness, and mass budget of the rocket. If mass and flight-time is not an issue, the probable best solution is an electric motor; but this requires a large battery (and suffers from scalability - large mass-flux rockets can't really work off an electric turbo pump) - so more often, the turbo either kicks in later or gets an electric start and eventually draws energy from the primary propulsion source. Nimur (talk) 16:56, 17 August 2009 (UTC)
 

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.

DETAILS

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

where:
A0 is the initial speed of sound of the exhaust gas
G is the ratio of specific heat at constant pressure to specific heat at constant volume

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:

  1. Liquid propellant rockets burn a mixture of liquid fuel and liquid oxidizer, e.g., hydrogen and oxygen. They have a high specific impulse (350-540 seconds) but require expensive turbopumps to feed fuel and oxidizer at a high pressure to the combustion chamber. The thrust-to-weight ratio of the Space Shuttle main engine is about 70. Russian NK-33 engine's thrust-to-weight ratio is approximately 125.

     

    Profile of liquid propellant rocket engine

 

Hiçbir yazı/ resim  izinsiz olarak kullanılamaz!!  Telif hakları uyarınca bu bir suçtur..! Tüm hakları Çetin BAL' a aittir. Kaynak gösterilmek şartıyla  siteden alıntı yapılabilir.

The Time Machine Project © 2005 Cetin BAL - GSM:+90  05366063183 -Turkiye/Denizli 

Ana Sayfa  / index /Roket bilimi / E-Mail / CetinBAL / New World Order(Macro Philosophy)

UFO Technology / Time Travel Technology/ Kuantum Fiziği