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rocket propellent ppt
- 1. Submitted by Dhirendra singh Roll no-1271940903 ME-3rd year 1
- 2. 1-Rocket principle 2-rocket propellant 3- type of rocket propellant â—Ź solid propellant rocket â—Ź liquid propellant rocket â—Źgas propellant rocket â—Ź hybrid propellent rocket 3- Rocket fuel selection 2
- 3. Rocket Principles ď‚—High pressure/temperature/velocity exhaust gases provided through combustion and expansion through nozzle of suitable fuel and oxidiser mixture. ď‚—A rocket carries both the fuel and oxidiser onboard the vehicle whereas an air-breather engine takes in its oxygen supply from the atmosphere.
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- 5. How Rocket Engines Operate Rocket propulsion is based on Sir Isaac Newton’s three laws of motion. The third law is the heart of rocketry because the action of the rocket engine produces the forward motion of the rocket.
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- 7. Types of Rocket Engines Solid Propellant • In a solid propellant rocket system the fuel and oxidizer are mixed together from the start. • The rocket case is the combustion chamber and holds the propellants. There are no valves, pumps, or sensors. Additives, if needed to increase temperature or to control burning, are simply mixed with propellant grains.
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- 9. SOLID ROCKETS AND NOZZLE FLOW ď‚—Special issue with solid propellants that use powdered metals as a fuel additive ď‚—Adding aluminum to formation of solid propellant increases gas temperature, but incurs performance penalties related to solid particles that are generated ď‚— Aluminum burns with oxygen to form Al2O3 particles ď‚—Particles are initially liquid and solidify during expansion process ď‚—Also tend to agglomerate to become large particles ď‚—Large particles do not accelerate as quickly as the gas surrounding them ď‚—These particles may constitute as much as 10-25% of total mass ď‚—Need to consider this in nozzle design, which must account for two-phase flow ď‚—Simplified models exist for analysis of performance: ď‚— Results indicate that large particle sizes are a detriment ď‚— However, for small particles, there is an optimum amount of Al to add 9
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- 11. Liquid propellant rocket Liquid Propellant Classifications • Monopropellants  Contains its oxidizer and fuel in one solution.  May be a single chemical compound.  The compounds are stable at ordinary temperatures and pressures, but break down when heated and pressurized, or when the breaking down process is started by a catalyst.  Monopropellant rockets are simple since they need only one propellant tank and associated equipment.
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- 14. Types of hybrid Rocket Engines Hybrid Propellant • Hybrid propellants combine in a single rocket engine many of the advantages of both liquid and solid propellant rockets. • Flexibility gives the hybrid rocket its biggest operational advantage. It can be throttled from zero to full thrust and can be stopped and started in flight.
- 15. 15 Solid Fuel, Liquid Oxidizer Example
- 16. ROCKET FUEL SELECTION GUIDE ď‚—Desirable Physical Properties ď‚— Low freezing point ď‚— High specific gravity (dense propellant) ď‚— Stability (with time) ď‚— Heat transfer properties ď‚— Pumping properties (low vapor pressure, low viscosity) ď‚— Small variation in physical characteristics with temperature ď‚— Ignition, combustion, and flame properties ď‚—Performance of Propellants ď‚—Economic Factors ď‚—Physical Hazards (Explosion, Fire, Spills) ď‚—Health Hazzards ď‚—Corrosion 16
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Editor's Notes
- Rocket propulsion is based on Sir Isaac Newton’s three laws of motion. The third law is the heart of rocketry because the action of the rocket engine produces the forward motion of the rocket.
- Solid Propellant The chemical system of a rocket may have a solid rather than a liquid propellant. In a solid propellant rocket system the fuel and oxidizer are mixed together from the start. The rocket case is the combustion chamber and holds the propellants. There are no valves, pumps, or sensors. Additives, if needed to increase temperature or to control burning, are simply mixed with propellant grains. The grains are made by passing a mixture of solid chemical fuel and oxidizers through a die. This produces a specially shape grain. Once the grain is ignited, it is capable of sustained burning. Fuels used in solid propellants include asphalts, waxes, oils, plastics, metal, rubbers, and resins. Ignited by a composition that both heats the grain to ignition temperature and increases the pressure in the combustion chamber until propellant reaction is assured. Older propellant mixtures could be ignited by the heat of a short-resistance electrical wire. This type of ignition device is found in model rocket-launching devices. Today’s rockets use devices like the squib. The squib consists of an enclosure filled with a combustible powder, which is ignited electrically. The flame of the burning squib ignites the grain.
- Liquid propellant classifications Monopropellants Contains its oxidizer and fuel in one solution. May be a single chemical compound, such as nitromethane, or a mixture of several chemicals compounds, such as hydrogen peroxide and alcohol. The compounds are stable at ordinary temperatures and pressures, but break down when heated and pressurized, or when the breaking down process is started by a catalyst. The most common monopropellant system uses hydrazine, a colorless fuming corrosive, and a catalyst. Generally, monopropellants also require more heat for ignition and react more slowly than bipropellants. These characteristics mean that monopropellants require larger combustion chambers. Monopropellant rockets are simple since they need only one propellant tank and associated equipment. The design of a liquid-monopropellant system is much simpler than that of a bipropellant system because a monopropellant systems requires only half the storage, pumping, and controlling equipment. The draw back is its sensitivity to temperatures and shock. This sensitivity results in instability and restricts its handling.
- Hybrid propellants combine in a single rocket engine many of the advantages of both liquid and solid propellant rockets. Hybrid propellant systems have the flexibility, controllability, and high performance of liquid-propellant rockets, plus the simplicity, reliability, and relative economy of solid-propellant rockets. Flexibility gives the hybrid rocket its biggest operational advantage. It can be throttled from zero to full thrust and can be stopped and started in flight. .