Electrically Operated Propellant for Solid Rocket Thrust Management

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Solution Overview

Problem

Solid rocket motors lack the ability to control thrust and thrust vectoring without complex valve systems, as they cannot be throttled or turned off once ignited, limiting flexibility and efficiency in thrust management.

Innovation Solution

The use of electrically operated propellants that can be injected upstream of the nozzle or at the nozzle throat to increase chamber pressure and reduce the effective throat area, or injected downstream for thrust vector control, allowing for both gross and fine thrust adjustments without the need for physical control valves.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If complex valve systems are used to control thrust and thrust vectoring in solid rocket motors, then thrust control capability is improved, but device complexity increases

Engineering Contradiction:
Improvethrust control capabilityVSAvoidvalve system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent replaces complex mechanical valve systems with electrically operated propellant injection systems. Electric actuators control the injection of propellant into the combustion chamber or nozzle throat, providing thrust control and vectoring capabilities through electrical signals rather than mechanical valve actuation, thereby reducing mechanical complexity while maintaining control functionality

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces an intermediary control system that uses electrically operated propellant injection as a mediator between the control system and the main propellant flow. By injecting small amounts of propellant at controlled locations (combustion chamber, throat, or downstream), the system achieves thrust modulation and vectoring without requiring direct mechanical intervention in the main propellant path

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If solid rocket motor propellants are ignited to produce thrust, then thrust generation is improved, but ability to throttle or turn off thrust deteriorates

Engineering Contradiction:
Improvethrust generationVSAvoidthrust throttling capability
Core Design Contradiction:
PowerVSEase of operation

Solution Approach 1:

The patent implements periodic or pulsed injection of electrically operated propellant to modulate thrust output. By controlling the timing, duration, and frequency of propellant injection pulses into the combustion chamber or nozzle, the system can throttle thrust levels and even temporarily halt thrust generation without requiring shutdown of the main propellant ignition, enabling flexible thrust management

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The patent changes operational parameters by injecting propellant at different locations (combustion chamber for pressure control, nozzle throat for area control, downstream for vectoring) and varying injection rates. These parameter changes allow continuous thrust modulation from full power to throttled levels, providing controllable thrust output while maintaining the ignited state of the main propellant

Inventive Principle:
Principle #35Parameter changes

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

Enables flexible and efficient thrust management by increasing chamber pressure and reducing the effective nozzle throat area, providing both thrust control and vectoring capabilities with minimal impact on the rocket's design and construction, while allowing for the propellant to be turned on and off at elevated pressures.

Implementation Method 1

The gas produced by combustion of the electrically operated propellant may be injected into the combustion chamber to increase chamber pressure

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

Nozzle includes a throat that pinches down to a minimum cross-section to accelerate the velocity of the mass passing from the combustion chamber to the atmosphere

Methodology Applied
Scientific EffectChoked flow:

Implementation Method 3

As shown, the nozzle is a convergent-divergent nozzle that accelerates the hot, pressurized gas passing through the throat to a higher supersonic speed by converting the heat energy of the flow into kinetic energy

Methodology Applied
Scientific EffectConvergent-divergent nozzle acceleration: De Laval Nozzle

Data Source

PatentEP3516196B1Electrically operated propellant for solid rocket motor thrust management
Publication Date: 2020.06.17 RAYTHEON CO
  • EP3516196B1 patent drawingFigure 1A~2
  • EP3516196B1 patent drawingFigure 3~4
  • EP3516196B1 patent drawingFigure 5A~5B

AI summary

Electrically operated propellant is used to supplement the thrust provided by solid rocket motor (SRM) propellant to manage thrust produced by a SRM. The gas produced by burning the electrically operated propellant may be injected upstream of the nozzle to add mass and increase chamber pressure Pc, injected at the throat of the nozzle to reduce the effect throat area At to increase chamber pressure Pc or injected downstream of the throat to provide thrust vector control or a combination thereof. Certain types of electrically operated propellants can be turned on and off provided the chamber pressure Pc does not exceed a self-sustaining threshold pressure eliminating the requirement for physical control valves.