Rocket Injector Element With Inclined Flow Splitter Slots

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Solution Overview

Problem

Conventional coaxial injector elements for rocket drives with hypergolic propellants suffer from reduced combustion efficiency due to limited contact area between propellants, leading to reduced engine power output, especially in small rocket drives with limited space for injector elements.

Innovation Solution

An injector element with a coaxial design featuring a central body and sleeve, where the flow splitter's slots are inclined relative to the radial axis, increasing the contact area between propellants and generating fine propellant jets, thereby enhancing combustion efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional radial slots are used in the flow splitter, then the structure is simple and easy to manufacture, but the contact area between propellants is limited resulting in reduced combustion efficiency

Engineering Contradiction:
Improveease of manufactureVSAvoidcombustion efficiency
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The patent applies asymmetry by inclining the slots relative to the radial direction. Instead of using conventional radial slots that are perpendicular to the axis of symmetry, the slots are inclined at an angle between 10° and 45° to the radial direction. This asymmetric configuration increases the contact area between the first and second propellants by extending the interaction path along the inclined slot surfaces, thereby improving combustion efficiency while maintaining manufacturing simplicity.

Inventive Principle:
Principle #4Asymmetry

2Reliability

If the number of injector elements is increased to improve combustion efficiency, then more propellant contact area is achieved, but the space requirements exceed available volume in small rocket drives

Engineering Contradiction:
Improvecombustion efficiencyVSAvoidvolume
Core Design Contradiction:
ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent utilizes another dimension by introducing an angular component to the slot configuration. Instead of only varying the number of slots (one-dimensional approach), the invention inclines the slots at an angle to the radial direction, creating a two-dimensional effect that extends the propellant contact path. This dimensional change allows a single injector element to achieve the combustion efficiency that would otherwise require multiple injector elements, thereby reducing the overall volume requirement.

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

3Reliability

If the slots are highly inclined to increase contact area, then combustion efficiency improves, but the structural complexity and manufacturing difficulty increase

Engineering Contradiction:
Improvecombustion efficiencyVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the inclination angle of the slots within a specific range (10° to 45°) relative to the radial direction. This parameter optimization balances the competing requirements: angles within this range provide sufficient contact area extension to improve combustion efficiency while remaining manufacturable with conventional techniques. The specified parameter range prevents excessive complexity that would arise from very high inclination angles while still achieving the desired performance improvement.

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

The inclined slots in the flow splitter increase the combustion efficiency, resulting in higher engine power output and stable combustion, even in small rocket drives with limited injector elements.

Implementation Method 1

The flow splitter is arranged between the central body and the sleeve for splitting the second propellant into a plurality of individual flows. The passage channels are slots wherein the long sides of the slots are inclined with regard to their radial extension to a longitudinal axis of the injector element, wherein the inclination of the long sides of the slots with regard to their radial extension to a longitudinal axis is greater than 0° and smaller than 60°. By inclining the slots of the flow splitter the contact area between the two propellants can be increased

Methodology Applied
Scientific EffectFluid mixing:

Data Source

PatentEP2757242B8Injector element for rocket engines
Publication Date: 2018.06.13 ARIANEGRP GMBH

AI summary

An injector element (1) of coaxial design is provided for a rocket drive for operation with a first and a second propellant, comprising a central body (5), a sleeve (2) and a flow splitter (7). The central body (5) comprises a flow channel with an outlet, the central body (5) generating a conical drop distribution at the outlet forming a fuel cone, wherein the first propellant, normally an oxidant, is provided in the central body (5). The sleeve (2) concentrically surrounds the central body (5) to form an annular flow channel for the second propellant, normally fuel. The flow splitter (7) is arranged between the central body (5) and the sleeve (2) for splitting the second propellant into a plurality of individual flows. The flow splitter (7) includes a given number of passage channels which are distributed around the central body (5), each of the passage channels for generating a fine propellant jet. The passage channels are slots (8) wherein the long sides of the slots (8) are inclined with regard to their radial extension to a longitudinal axis of the injector element (1).