Nitrous oxide fuel blend
Encyclopedia
Nitrous Oxide Fuel Blend propellants are a class of liquid rocket propellants
. The fuel and oxidizer are blended and stored, and are sometimes referred to as 'mixed monopropellant
s'. Upon use, the propellant is heated or passed over a catalyst bed and the Nitrous oxide decompose into oxygen-rich gasses. Combustion then ensues. Special care is needed in the chemical formulation and engine design to prevent detonating the stored fuel.
NOFBX is a recent example, developed by Firestar Technologies LLC.
decomposes into hot oxygen-rich air, and requires no separate supply of oxidizer such as the liquid oxygen
used in many high performance rocket engines today. Consequently, it can be used as a monopropellant by itself. For added performance nitrous oxide may also be blended with a range of different fuels and emulsifiers. Such a blend of an oxidizer and a fuel is called a mixed monopropellant. It combines the simplified plumbing of a monopropellant with the performance of a bipropellant.
. The promise of high performance, greater range and lighter feed systems drove experimentation with blends of nitrous oxide and ammonia, which resulted in numerous explosions and demolished motors.
Until recently, (~2003) the complexities involved in building propulsion systems that can safely handle nitrous oxide fuel blend monopropellants have been a deterrent to serious development since the end of WWII.
, Innovative Space Propulsion Systems plans to test the NOFBX mono-propellant on the International Space Station
in late 2012.
and is less toxic than other monopropellants currently used in space applicatons, such as hydrazine
. Flight testing of NOFBX engines is planned on the ISS in 2012.
NOFBX has been used to fuel a reciprocating engine
to power high-altitude, long-endurance drone aircraft
under a DARPA
contract.
"NOFBX is being promoted as a “game changing” technology with the following characteristics:
G.S. Mungas, D.J. Fisher, J.A. Smith, K.W. Doyle, G.H. Peters, A.P. London, L. Droppers, J. Fryer, S. Coley, T. Delange, NOFBX™ COLT Engine Development and Testing, Joint Army, Navy, NASA, Air Force (JANNAF) Interagency Propulsion Conference, SPS-IIE-3, CPIA/JHU, Colombia, MD (May 2010)
G.S. Mungas, D.J. Fisher, C.B. Mungas, B. Carryer, NOFB Monopropellants – Background, Characterization, and Testing. Joint Army, Navy, NASA, Air Force Interagency Propulsion Conference (JANNAF), SPS-I-11, CPIA/JHU, Colombia, MD (Dec 2008)
Liquid rocket propellants
The highest specific impulse chemical rockets use liquid propellants. This type of propellant has a long history going back to the first rockets and is still in use, for example in the Space Shuttle and Ariane 5.-Early development:...
. The fuel and oxidizer are blended and stored, and are sometimes referred to as 'mixed monopropellant
Monopropellant
Monopropellants are propellants composed of chemicals or mixtures of chemicals which can be stored in a single container with some degree of safety. While stable under defined storage conditions, they react very rapidly under certain other conditions to produce a large volume of energetic gases...
s'. Upon use, the propellant is heated or passed over a catalyst bed and the Nitrous oxide decompose into oxygen-rich gasses. Combustion then ensues. Special care is needed in the chemical formulation and engine design to prevent detonating the stored fuel.
NOFBX is a recent example, developed by Firestar Technologies LLC.
Overview
Nitrous oxideNitrous oxide
Nitrous oxide, commonly known as laughing gas or sweet air, is a chemical compound with the formula . It is an oxide of nitrogen. At room temperature, it is a colorless non-flammable gas, with a slightly sweet odor and taste. It is used in surgery and dentistry for its anesthetic and analgesic...
decomposes into hot oxygen-rich air, and requires no separate supply of oxidizer such as the liquid oxygen
Liquid oxygen
Liquid oxygen — abbreviated LOx, LOX or Lox in the aerospace, submarine and gas industries — is one of the physical forms of elemental oxygen.-Physical properties:...
used in many high performance rocket engines today. Consequently, it can be used as a monopropellant by itself. For added performance nitrous oxide may also be blended with a range of different fuels and emulsifiers. Such a blend of an oxidizer and a fuel is called a mixed monopropellant. It combines the simplified plumbing of a monopropellant with the performance of a bipropellant.
History
German rocket scientists were experimenting with nitrous oxide fuel blends as early as 1937. Nitrous oxide fuel blends testing continued throughout World War IIWorld War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
. The promise of high performance, greater range and lighter feed systems drove experimentation with blends of nitrous oxide and ammonia, which resulted in numerous explosions and demolished motors.
Until recently, (~2003) the complexities involved in building propulsion systems that can safely handle nitrous oxide fuel blend monopropellants have been a deterrent to serious development since the end of WWII.
, Innovative Space Propulsion Systems plans to test the NOFBX mono-propellant on the International Space Station
International Space Station
The International Space Station is a habitable, artificial satellite in low Earth orbit. The ISS follows the Salyut, Almaz, Cosmos, Skylab, and Mir space stations, as the 11th space station launched, not including the Genesis I and II prototypes...
in late 2012.
NOFBX
NOFBX is the trademarked name for a proprietary nitrous oxide/fuel/emulsifer blended mono-propellant developed by Firestar Technologies LLC.. NOFBX has a higher ISPSpecific impulse
Specific impulse is a way to describe the efficiency of rocket and jet engines. It represents the derivative of the impulse with respect to amount of propellant used, i.e., the thrust divided by the amount of propellant used per unit time. If the "amount" of propellant is given in terms of mass ,...
and is less toxic than other monopropellants currently used in space applicatons, such as hydrazine
Hydrazine
Hydrazine is an inorganic compound with the formula N2H4. It is a colourless flammable liquid with an ammonia-like odor. Hydrazine is highly toxic and dangerously unstable unless handled in solution. Approximately 260,000 tons are manufactured annually...
. Flight testing of NOFBX engines is planned on the ISS in 2012.
NOFBX has been used to fuel a reciprocating engine
Reciprocating engine
A reciprocating engine, also often known as a piston engine, is a heat engine that uses one or more reciprocating pistons to convert pressure into a rotating motion. This article describes the common features of all types...
to power high-altitude, long-endurance drone aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...
under a DARPA
Defense Advanced Research Projects Agency
The Defense Advanced Research Projects Agency is an agency of the United States Department of Defense responsible for the development of new technology for use by the military...
contract.
"NOFBX is being promoted as a “game changing” technology with the following characteristics:
- constituents are widely available from chemical suppliers, inexpensive and safe to handle.
- can be transported and handled without undue precautions or hazards.
- effluents are non-toxic and produces no accumulated deposits or contamination.
- propulsion system has high Isp (320-340 s) – similar to the most common bi-propellant.
- has far better lift capability than the current workhorse monopropellant, hydrazine.
- is tolerant to a wide thermal range; storable at room temperature on the ground and is Space-storable.
- [is projected to] lower cost compared to existing propulsion systems of comparable performance.
- is monopropellant, which significantly reduces the need for auxiliary hardware, saving cost, volume, and mass for launch systems.
- utilizes cool running thrusters that dramatically reduce thermal design challenges.
- burns in liquid, gas, and two-phase flow.
- does not have the materials compatibility constraints of traditional hypergolic systems."
Safety Concerns
Recent work on the decomposition of nitrous oxide has raised concerns about the safety risks of mixing hydrocarbons with nitrous oxide. By adding hydrocarbons, the barrier to an explosive decomposition event is lowered significantly.External links
Further reading
G.S. Mungas, Regeneratively-Cooled, Vortex-Jacket, Fluids and Heat Transfer Model for Rocket Combustion Chambers, Joint Army, Navy, NASA, Air Force (JANNAF) Interagency Propulsion Conference, LPS-IIP-3, CPIA/JHU, Colombia, MD (May 2010)G.S. Mungas, D.J. Fisher, J.A. Smith, K.W. Doyle, G.H. Peters, A.P. London, L. Droppers, J. Fryer, S. Coley, T. Delange, NOFBX™ COLT Engine Development and Testing, Joint Army, Navy, NASA, Air Force (JANNAF) Interagency Propulsion Conference, SPS-IIE-3, CPIA/JHU, Colombia, MD (May 2010)
G.S. Mungas, D.J. Fisher, C.B. Mungas, B. Carryer, NOFB Monopropellants – Background, Characterization, and Testing. Joint Army, Navy, NASA, Air Force Interagency Propulsion Conference (JANNAF), SPS-I-11, CPIA/JHU, Colombia, MD (Dec 2008)