Chemical Power Systems Flashcards
What is the difference between bi-propellant staged combustion liquid rocket engine cycle and full–flow staged liquid rocket engine cycle
different:
bi-propellant tanks contain an oxidiser storage unit, from which the oxidizer is injected into the precombustion chamber, and ignited before entering the fuel tank
full-flow both the fuel and oxidizer are fully flowed through the engine cycle separately
Explain what would be common parts between bi-propellant combustion and full-flow staged liquid rocket engine cycle
common:
Liquid propellant tanks: Both engine cycles require separate tanks to store the oxidizer and fuel liquids.
Injectors: Both engine cycles use injectors to mix the oxidizer and fuel before they are burned.
Combustion chamber: Both engine cycles have a combustion chamber where the mixed propellants are burned to generate hot gases and thrust.
Nozzle: Both engine cycles use a nozzle to direct the hot gases out of the engine to create thrust.
What is the difference between function of inhibitor in solid rocket motor and the inhibitor used in liquid rocket engines?
Solid Rocket Motors:
-Inhibitor is an additive in solid rocket propellant.
-Slows down the rate of combustion.
-Acts as a flame suppressant or combustion rate modifier.
-Prevents uncontrolled combustion and excessive pressure buildup.
-Mixed with solid propellant during manufacturing process.
Liquid Rocket Engines:
-Inhibitors prevent unwanted chemical reactions or reactions between propellants.
-Used to prevent propellant decomposition or other undesirable reactions.
-Ensure safe and reliable operation, protect engine components, and maintain performance.
-Added to propellants or used in engine design.
-Do not directly control combustion rate as in solid rocket motors.
What would be the main oxidizing substance used in composite solid rocket propellant and provide its chemical formula?
Ammonium Perchlorate (NH4ClO4)
What is the difference between the terms “specific impulse” and “total impulse” for a rocket motor (use the mathematical equations to answer the question)?
The specific impulse, Isp, with units of seconds, is the total impulse divided by the amount of propellant that produced that amount of impulse.
Total impulse is the product of thrust times duration of the motor burn time, and is measured in Newton-seconds (Ns). This measures the total amount of momentum imparted to the rocket by the motor.
Which type of the propellant would be most suitable for each of the following applications:
(i) Booster for the satellite launch vehicle
Solid Propellant in Solid Rocket Motors
Which type of the propellant would be most suitable for each of the following applications:
ii) Main engine of the satellite launch vehicle
Cryogenic Liquid Bi-propellant
Which type of the propellant would be most suitable for each of the following applications:
(iii) Rocket engine for the satellite manoeuvrings
Liquid Mono-Propellants
For a stoichiometric mixture, which bi-propellant combination of liquid oxidizer and liquid fuel
has the highest specific impulse amongst the liquid rocket propellants?
hydrogen fuel & oxygen oxidider
Name any two (out of six) types of the liquid rocket engine cycles?
- Gas Generator Type
- Staged combustion rocket cycle
- Full Flow Staged cumbustion
- Expander cycle
- Expanded bleed cycle
- Pressure fed cycle.
Which chemical substance is primarily used as oxidiser in contemporary composite solid rocket propellants? What is the chemical formula of the substance in question?
Ammonium Perchlorate (NH4ClO4)
Describe what is meant by the term ‘chemical erosion’ and how it can be mitigated
The degradation or erosion of propulsion system components in space due to chemical reactions with propellants or other chemicals, caused by the corrosive nature of propellants and extreme conditions of space.
Mitigation Strategies:
-Propellant selection:
-Propellant handling and storage:
-Propellant purification:
-Protective coatings:
-Component materials selection:
-Regular inspection and maintenance:
-Testing and qualification:
What is plasma
Plasma: it is designated as the fourth state of matter (the others are solid, liquid, and gas). It has some of the properties of a gas but is affected by electric and
magnetic fields
What is the working principle of arcjet thruster?
The arcjet utilizes an electric arc to directly heat the propellant stream. Since the arcjet is not in direct contact with the wall the arcjet can heat the propellant to significantly higher temperatures than the resistojet without increasing the wall temperature.
describe the operating principle of a liquid rocket engine with a “pressure fed” working cycle.
1.Propellant Storage: The engine has separate tanks for storing the fuel and oxidizer. These tanks are pressurized with a gas, such as helium or nitrogen, to create a positive pressure that forces the propellants to flow towards the combustion chamber.
2.Propellant Flow: The pressurized propellants flow from their respective storage tanks through separate feed lines and into the combustion chamber. The propellants are fed at a constant flow rate, which is determined by the pressure of the propellant tanks.
3.Combustion: Once the propellants enter the combustion chamber, they are ignited to initiate combustion. The combustion process generates a high-pressure gas that expands and accelerates out of the nozzle, producing thrust.
4.Thrust: The high-pressure gases exiting the nozzle create a forward thrust that propels the rocket forward. The thrust is proportional to the mass flow rate of the propellants and the velocity of the exhaust gases.
5.Control: The flow rate of the propellants and the thrust of the engine can be controlled by adjusting the pressure in the propellant tanks. By increasing or decreasing the pressure, the flow rate and thrust can be varied as needed for the desired performance of the rocket.
