External Rotor Actuator for Rocket Nozzle Throat Control
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Solution Overview
Problem
Existing rocket nozzle designs face challenges in efficiently varying thrust due to changes in altitude and environmental conditions, as internal pintle actuation systems are prone to breakdown from harsh conditions and are difficult to maintain, and often consume valuable space within the propulsion system.
Innovation Solution
A pintle-controlled propulsion system with an external rotor that encircles the gas flow sections, allowing for changes in the annular throat area through rotary motion translated into linear motion of either the pintle or the motor shell, thereby varying the nozzle throat area externally, reducing the risk of breakdown and maintaining efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an internal pintle actuation system is used, then thrust control is achieved, but the system is prone to breakdown from harsh conditions and difficult to maintain
Solution Approach 1:
The actuation system is extracted from the internal combustion chamber environment and relocated to the external motor casing. The external actuator rotates the motor casing or pintle assembly from the outside, removing the actuation mechanism from the harsh thermal and chemical conditions inside the combustion chamber, thereby improving reliability and ease of maintenance.
2Adaptability or versatility
If an internal pintle actuation system is used, then thrust control is achieved, but valuable space within the propulsion system is consumed
Solution Approach 1:
The actuation mechanism is extracted from the internal volume of the propulsion system and positioned externally. This allows the combustion chamber and nozzle internal volume to be fully utilized for propellant and thrust generation, while the actuator is mounted on the external motor casing.
3Productivity
If the nozzle throat area is varied to adapt to altitude changes, then thrust optimization is achieved, but the actuation system must operate in harsh thermal and chemical conditions
Solution Approach 1:
The actuator is extracted from the harsh internal environment and mounted externally on the motor casing. It controls the nozzle throat area by rotating the motor casing or pintle assembly from the outside, thereby achieving thrust optimization without exposing the actuation mechanism to high temperatures and chemical corrosion.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables flexible and efficient thrust control by maintaining combustion efficiency and reducing the risk of system failure, while minimizing weight and space consumption within the rocket motor.
Implementation Method 1
the rotary motion is translated into linear motion of either the pintle or the motor shell that encompasses the nozzle at the throat and surrounds the pintle, thereby changing the position of the pintle relative to the nozzle and varying the annular throat area
Implementation Method 2
as propellant supply is gradually depleted, the rate at which combustion gases are generated often decreases, causing a drop in chamber pressure
Data Source
AI summary
A propulsion system with a divergent-convergent nozzle is provided with variable thrust by a pintle whose position relative to the nozzle throat is controlled by an actuator that includes a rotor that external to, and encircling, the nozzle, and that is coupled to either the pintle or to the nozzle shell by a linkage that translates the rotary movement of the rotor into linear movement of either the pintle or the shell.