Question

A grain in which thrust, pressure and burning surface area increase with burn time is called as

• A. neutral burning
• B. progressive burning
• C. regressive burning
• D. normal burning

Hint:

Progressive burning is often used to achieve higher thrust later in the burn cycle.

Answer 1

The Correct Option is B

Explanation: In rocketry and aerospace engineering, the behavior of the propellant grain as it burns determines the thrust and pressure dynamics within the combustion chamber. These dynamics are critical for the performance and stability of the rocket.

Grain types are classified based on how their surface area changes during combustion:

• Neutral Burning: The burn surface area remains constant throughout the burn. This results in a steady thrust and chamber pressure.
• Progressive Burning: The burn surface area increases as combustion progresses. This causes an increase in thrust and pressure, which is usually desirable for missiles and rockets that need increased acceleration over time.
• Regressive Burning: The burn surface area decreases as combustion progresses, leading to a decrease in thrust and pressure, often used in applications where initial high thrust is needed.
• Normal Burning: This term is generally not used to specifically categorize grain types in advanced propellant systems.

Based on the given options and explanation, a grain in which thrust, pressure, and burning surface area all increase with burn time is referred to as progressive burning.