Segmented Solid Rocket Propellant Grain Design

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Solution Overview

Problem

Existing solid rocket propellant grains either produce high thrust with short burning time or low thrust with long burning time, making it difficult to achieve intermediate values without changing the propellant material or combustion chamber design significantly.

Innovation Solution

A solid rocket propellant grain design featuring a combination of first and second type layers, where the first type layer is completely filled with solid propellant and has an inhibited lateral surface, and the second type layer has recesses in the solid propellant with a non-inhibited lateral surface, allowing for a cylindrical shape with interconnected layers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a cylindrical grain with a core channel along its entire length is used, then high thrust is achieved, but burning time becomes short

Engineering Contradiction:
ImprovethrustVSAvoidburning time
Core Design Contradiction:
PowerVSDuration of action of moving object

Solution Approach 1:

The grain is divided into multiple longitudinal segments separated by transverse slots, creating a segmented core channel structure. This segmentation allows the burning front to progress through multiple paths simultaneously, extending burning time while maintaining high thrust through the distributed combustion zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces transverse slots that extend the burning path from a single axial dimension to multiple radial dimensions. The burning front progresses both axially through the core channel and radially through the slots, creating a multi-dimensional combustion pattern that extends burning time without sacrificing thrust.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Duration of action of moving object

If a grain without a core channel with inhibited outer surface is used, then low thrust is achieved, but burning time becomes long

Engineering Contradiction:
Improveburning timeVSAvoidthrust
Core Design Contradiction:
Duration of action of moving objectVSPower

Solution Approach 1:

The grain structure incorporates transverse slots that segment the propellant mass into multiple combustion zones. This segmentation creates multiple burning fronts that progress simultaneously, increasing the overall burning rate and thrust while maintaining extended burning time through the distributed combustion paths.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The transverse slots introduce radial combustion paths in addition to axial burning, creating a multi-dimensional combustion pattern. This allows the burning front to progress through multiple directions simultaneously, increasing thrust while maintaining long burning time through the extended combustion path.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Power

If propellant material or combustion chamber dimensions are changed to obtain intermediate thrust and operating time values, then intermediate performance is achieved, but design complexity increases

Engineering Contradiction:
ImprovethrustVSAvoiddesign complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The grain structure uses simple transverse slots cut through the propellant mass to create segmented combustion zones. This segmentation approach provides intermediate thrust and burning time characteristics without requiring complex propellant formulations or combustion chamber redesign, maintaining design simplicity while achieving performance flexibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention modifies local regions of the grain by introducing transverse slots at specific positions and depths. This local modification creates varied burning paths and combustion zones that provide intermediate performance characteristics without requiring changes to the overall propellant material or combustion chamber design.

Inventive Principle:
Principle #3Local quality

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 design enables the achievement of intermediate thrust and operating time values without altering the propellant material or combustion chamber design, providing a wide range of propellant burning areas and thrust profiles, thus allowing for more flexible rocket motor operation.

Implementation Method 1

a solid propellant material with an inhibited lateral surface... a non-inhibited lateral surface... providing a wide range of propellant burning areas and thrust profiles

Methodology Applied
Scientific EffectCombustion: Combustion

Data Source

PatentEP4159999B1Rocket solid propellant grain
Publication Date: 2025.02.12 SIEC BADAWCZA LUKASIEWICZ INSTYTUT LOTNICTWA
  • EP4159999B1 patent drawingFigure 1
  • EP4159999B1 patent drawingFigure 2
  • EP4159999B1 patent drawingFigure 3

AI summary

The subject of the invention is a solid rocket propellant grain comprising frontal surfaces and a lateral surface, characterised in that it comprises a first type layer which is completely filled in cross-section with a solid propellant material with an inhibited lateral surface (101a), and a second type layer which has at least one recess (103) in a solid propellant material with a non-inhibited lateral surface (101b), wherein at least one second type layer is surrounded by the first type layer on both sides.