Alternating Swirl Rocket Injector for Combustion Mixing

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Solution Overview

Problem

Conventional liquid propellant rocket engines face challenges in achieving efficient mixing and combustion of fuel and oxidizer propellants, leading to suboptimal thrust performance and potential hot streaks at combustor walls.

Innovation Solution

The design incorporates an injector with a unique array of injector elements, featuring central axial passages for oxidizer injection and peripheral transverse passages for swirl injection of fuel, with alternating clockwise and counter-clockwise swirl directions between circumferential rows to enhance mixing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional injector elements with single-direction swirl are used, then the structure is simple, but mixing efficiency is insufficient leading to suboptimal thrust performance

Engineering Contradiction:

Improvethrust performanceVSAvoidinjector element configuration

Core Design Contradiction:

ProductivityVSDevice complexity

Solution Approach 1:

The injector elements are segmented into different circumferential rows, with each row containing injector elements that provide swirl injection flow in the same direction (either all clockwise or all counter-clockwise). This segmentation allows for systematic organization of alternating swirl directions across rows while maintaining manufacturing simplicity within each row.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different circumferential rows are assigned different swirl directions (clockwise or counter-clockwise) to create local variations in flow patterns. This local quality differentiation enhances overall mixing efficiency by creating complementary swirl interactions between adjacent rows, while each individual row maintains a uniform configuration that is simple to manufacture.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If conventional single-direction swirl injection is used, then manufacturing is simple, but hot streaks occur at combustor walls

Engineering Contradiction:

Improvehot streaks at combustor wallsVSAvoidalternating swirl direction configuration

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The injector employs asymmetric swirl directions in alternating circumferential rows, with some rows producing clockwise swirl and others producing counter-clockwise swirl. This asymmetry prevents the formation of coherent hot streaks that would occur with uniform single-direction swirl, as the opposing swirl directions create complementary mixing patterns that distribute heat more evenly across the combustor wall surface.

Inventive Principle:

Principle #4Asymmetry

3Speed

If injector elements provide only axial injection flow, then the structure is simple, but mixing and burning speed is insufficient

Engineering Contradiction:

Improvemixing and burning speedVSAvoidperipheral transverse passages configuration

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The injector elements incorporate peripheral transverse passages that introduce swirl injection flow in addition to the central axial injection flow. This adds a rotational dimension to the injection pattern, creating spiral flow paths that dramatically enhance mixing and burning speeds compared to pure axial injection, while the modular passage configuration keeps the structural complexity manageable.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 configuration promotes faster mixing and burning, shortening the axial length of the oxidizer stream and reducing the occurrence of hot streaks at combustor walls, thereby improving thrust performance and efficiency.

Implementation Method 1

The peripheral transverse passages are configured to provide swirl injection flow about the axial injection flow

Methodology Applied

Scientific EffectSwirl flow: Vortex Ring

Data Source

PatentUS20250137419A1Injector with injector elements in circumferential rows that alternate between counter-clockwise and clockwise swirl

Publication Date: 2025.05.01 AEROJET ROCKETDYNE INC

AI summary

An injector for a liquid rocket engine includes an array of injector elements. Each injector element includes a central passage and a plurality of peripheral transverse passages. The central passages are configured to provide axial injection flow and the peripheral transverse passages are configured to provide swirl injection flow. A portion of the injector elements provide the swirl injection flow in a clockwise direction and another portion of the injector elements provide the swirl injection flow in a counter-clockwise direction. The injector elements are arranged with a single, center injector element and a plurality of circumferential rows disposed around the single, center injector element. The injector elements of each one of the circumferential rows are either all of the clockwise direction or all of the counter-clockwise direction, and from the single, center injector element moving radially outwardly the circumferential rows alternate between the clockwise direction and the counter-clockwise direction.