Rocket Propellents Preparation and Properties
→ Substances used for launching rockets are called rocket propellants. These are the combination of an oxidiser and a fuel.
→ Rocket propellents are mixture of oxidismg substance and fuel. This fuels release hot gases after combustion in the engine. These gases escape out of nozzle which gives sufficient energy to rocket to move up.
Characteristics of Rocket Propellents
Rocket propellants possess unique properties, such as:
- Rocket propellent should be in solid state or liquid state which takes less space to store.
- The mixture of fuel and an oxidiser should be prepared quickly.
- The mixture should be highly inflammable which can give sufficient energy to speed up the rocket.
- It should not give any residue on combustion.
- Their chemical reaction should be fast.
Types of Rocket Propellents
Rocket propellents can be classified on the basis of their physical state:
- Solid Propellents
- Liquid Propellents
- Mixed or Hybrid Propellents
Solid Propellents : In this type of propellents, both the oxjdjser and fuel are in solid state. These are of two types:
- Combined and
→ Combined solid propellents are most common and are generally used. These are made up of fuel, oxidiser and combining material. Polyurethane or polybutandiene is used as a fuel, Ammonium sulphate is used as oxidiser and finely divided magnesium is used as combining material.
→ Dibasic propellents are made up of nitroglycerine and nitrocellulose.
→Liquid Propellents : In these, both oxidiser and fuel are in liquid state. These are most commonly used because these have more thrušting power as compared to solid propellents. These can be controlled. These are of two types :
- mono and
→ Mono propellents are the propellents in which both fuel and oxidiser works. These release large amounts of hot gases on combustion. For example hydrazine, nitromethane, hydrogen peroxide etc. Bi-propellents are those which contains mixture of two liquids in which one liquid acts as fuel and other as oxidiser. Kerosene oil, alcohol, hydrazine etc are used as fuelland liquid oxygen, liquid nitrogen etc. are used as oxidiser.
→ Mixed or Hybrid Propellents are mixture of solid and liqiid propellents. For example, mixture of acrylic rubber (as a fuel) and liquid nitrogen tetroxide as oxidiser.
Some Commonly Used Propellents
- In America, mixture of kerosene oil and liquid oxygen is used j.n saturn booster rocket initially but later mixture of liquid hydrogen and liquid oxygen was used.
- Mixture of kerosene oil and liquid oxygen is used in rocket Proton in Russia.
- In India, solid propellents are used in SLV and ASLV.