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Information about Working Fluid

Working mass is a mass against which a system operates in order to produce acceleration. All acceleration requires an exchange of momentum, which can be thought of as the "unit of movement". Momentum is related to mass and velocity, as given by the formula P = mv, where P is the momentum, m the mass, and v the velocity. The velocity of a body is easily changeable, but in most cases the mass is not, which makes it important. In rockets, the total velocity change can be calculated (using the Tsiolkovsky rocket equation) as follows:



Where:
  • v = ship velocity.
  • u = exhaust velocity.
  • M = ship mass, not including the fuel.
  • m = total mass ejected from the ship (working mass).
The term working mass is used primarily in the aerospace field. In more "down to earth" examples the working mass is typically provided by the Earth, which contains so much momentum in comparison to most vehicles that the amount it gains or loses can be ignored. However in the case of an aircraft the working mass is the air, and in the case of a rocket, it is the rocket fuel itself. Most rocket engines use light-weight fuels (liquid hydrogen, oxygen, or kerosene) accelerated to super-sonic speeds. However, ion engines often use heavier elements like Xenon as the reaction mass, accelerated to much higher speeds using electric fields.

In most cases the working mass is separate from the energy used to accelerate it. In a car the engine provides power to the wheels, which then accelerates the Earth backward to make the car move forward. This is not the case for most rockets however, where the rocket fuel is the working mass, as well as the energy source. This means that rockets stop accelerating as soon as they run out of fuel, regardless of other power sources they may have. This can be a problem for satellites that need to be repositioned often, as it limits their useful life. In general, rocket fuels can provide more energy than they can use, which leads to a number of techniques designed to provide external working mass in order to carry a smaller fuel load. These air-augmented rockets are only useful on rockets that travel through the atmosphere, and have not been used in service.

See also

acceleration is defined as the rate of change of velocity, or, equivalently, as the second derivative of position. It is thus a vector quantity with dimension length/time². In SI units, acceleration is measured in metres/second² (m·s-²).
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momentum (pl. momenta; SI unit kg m/s, or, equivalently, N•s) is the product of the mass and velocity of an object. For more accurate measures of momentum, see the section "modern definitions of momentum" on this page.
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Tsiolkovsky's rocket equation, or ideal rocket equation is named after Konstantin Tsiolkovsky who independently derived it and published in his 1903 work,[1]
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Please help [ improve this article] by expanding this section.
See talk page for details. Please remove this message once the section has been expanded. (tagged since March 2007)

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aircraft is a vehicle which is able to fly through the air (or through any other atmosphere). All the human activity which surrounds aircraft is called aviation. (Most rocket vehicles are not aircraft because they are not supported by the surrounding air).
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rocket is a vehicle, missile or aircraft which obtains thrust by the reaction to the ejection of fast moving fluid from within a rocket engine.

The history of rockets goes back to at least the 13th century[1].
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1, −1
(amphoteric oxide)
Electronegativity 2.20 (Pauling scale) More

Atomic radius 25 pm
Atomic radius (calc.) 53 pm
Covalent radius 37 pm
Van der Waals radius 120 pm
Miscellaneous

Thermal conductivity (300 K) 180.
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2, −1
(neutral oxide)
Electronegativity 3.44 (Pauling scale)
Ionization energies
(more) 1st: 1313.9 kJmol−1
2nd: 3388.3 kJmol−1
3rd: 5300.5 kJmol−1

Atomic radius 60 pm
Atomic radius (calc.
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Kerosene, sometimes spelled kerosine in scientific and industrial usage,[1] is a flammable hydrocarbon liquid. The name is derived from Greek "keros" (κηρός wax).
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ion thruster (more specifically an electrostatic ion thruster) is one of several types of spacecraft propulsion, specifically electric propulsion. It uses beams of ions — electrically charged atoms or molecules — for propulsion.
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Xenon (IPA: /ˈzɛnɒn, ˈziːnɒn/) is a chemical element that has the symbol Xe and atomic number 54.
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energy (from the Greek ενεργός, energos, "active, working")[1] is a scalar physical quantity that is a property of objects and systems of objects which is conserved by nature.
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Air-augmented rockets (also known as rocket-ejector, ramrocket, ducted rocket, integral rocket/ramjets, or ejector ramjets) use the supersonic exhaust of some kind of rocket engine to further compress air collected by ram effect during flight to use as additional working mass,
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Tsiolkovsky's rocket equation, or ideal rocket equation is named after Konstantin Tsiolkovsky who independently derived it and published in his 1903 work,[1]
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