JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD
JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III ROCKET AND SPACECRAFT PROPULSION Previous Question Paper (February/March - 2022 - R16)
Answer any five questions. All questions carry equal marks.
Main
What are the various methods used for propellant feed systems and explain about gas pressure feed system?
Answer
- Propellant Feed Systems are categorized primarily into Gas Pressure Feed Systems, Turbopump Feed Systems, and Electric Pump Feed Systems.
- In a Gas Pressure Feed System, a high-pressure inert gas (typically Helium or Nitrogen) is stored in a tank and regulated to a pressure higher than the combustion chamber pressure. This gas is introduced into the propellant tanks, forcing the fuel and oxidizer into the combustion chamber.
- Key components include high-pressure gas storage bottles, pressure regulators, check valves, and propellant tanks.
- Advantages: Simplicity, high reliability due to fewer moving parts, and suitability for restartable engines or attitude control thrusters.
- Disadvantages: Significant weight penalty due to the heavy, thick-walled propellant tanks required to withstand high internal pressures, making it inefficient for large-scale launch vehicles.
Explain about hot surface igniters.
Answer
- Hot Surface Igniters, often referred to as glow plugs or hot-wire igniters, operate on the principle of Joule heating.
- The system consists of a resistive element (typically made of high-melting-point alloys like Platinum, Tungsten, or Kanthal) that is heated to a temperature exceeding the auto-ignition temperature of the propellant mixture.
- Upon activation, an electric current is passed through the element, causing it to glow intensely. When the propellant (or a small pilot flow) comes into contact with this heated surface, the chemical reaction is initiated.
- Operational characteristics: These igniters are highly effective for small-to-medium liquid rocket engines and are frequently used in bipropellant thrusters where simple, reliable, and low-power ignition is required.
- Design considerations: The material must possess high thermal shock resistance and oxidation resistance to survive the harsh environment of the combustion chamber.
- Advantages: They provide a compact, non-pyrotechnic solution that allows for multiple ignition cycles without the need for replacing consumable cartridges.
How the flow distribution is designed in the combustion chamber for obtaining maximum combustion efficiency?
Answer
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How the pressurized feed systems are used in the combustion chamber for effective functioning of fuel?
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What are the major components of a missile and explain about propulsion system?
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What are the various forces coming on to the rocket and explain the importance of thrust?
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What are the various sources to be considered in the dispersion of missile and explain about launcher deflection.
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What is the effect of lateral aerodynamic moment and lateral damping moment of the rocket?
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How the space flight performance is obtained in gravity free environment?
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What are the forces acting on a space vehicle when it is in the atmosphere and mention their effects?
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What are the reasons for increase of thrust for ascending rockets?
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What is the effect of gravitational field on the velocity of the space craft?
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What are the various feedback controls used to have correct trajectory of a missile?
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How the control engine starting and thrust building is done?
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What are the adverse conditions developed during the flight travel and explain the materials used in these circumstances?
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What materials are selected for structural parts, nozzles, nose end of rockets?
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