Rocket Thrust Nozzle Contour Segmentation

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Solution Overview

Problem

Current thrust nozzles for rocket engines face challenges in preventing flow separation and associated lateral forces during start-up and stationary operation, as they either produce internal shocks or result in suboptimal nozzle pressure, failing to simultaneously achieve minimal lateral forces and maximum specific vacuum impulse.

Innovation Solution

A thrust nozzle design combining a convergent section with a divergent wall section featuring a first region as a truncated ideal nozzle and a second region with a deviating wall contour, such as a paraboloid shape, to suppress internal shocks and maintain high outlet pressure, thereby preventing flow separation and maximizing thrust.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If a parabolic TOP nozzle contour is used, then the nozzle outlet pressure is increased, but internal shocks occur causing flow separation with reattachment and high lateral forces

Engineering Contradiction:

Improvenozzle outlet pressureVSAvoidinternal shocks and lateral forces

Core Design Contradiction:

Stress or pressureVSObject-generated harmful factors

Solution Approach 1:

The divergent wall section is divided into two distinct regions: a first region with truncated ideal nozzle contour and a second region with deviating wall contour. This segmentation allows the nozzle to avoid internal shocks in the first region while maintaining high outlet pressure through the second region, thereby preventing flow separation with reattachment and reducing lateral forces.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different sections of the nozzle are given different wall contour properties tailored to their specific functional requirements. The first region uses a truncated ideal contour optimized for shock-free expansion, while the second region uses a deviating contour optimized for pressure maintenance, creating local optimization throughout the nozzle structure.

Inventive Principle:

Principle #3Local quality

2Object-generated harmful factors

If a truncated ideal nozzle (TIC) contour is used, then flow separation with reattachment is prevented, but the nozzle outlet pressure is much lower leading to flow separation in stationary operation

Engineering Contradiction:

Improvelateral forces during start-upVSAvoidnozzle outlet pressure

Core Design Contradiction:

Object-generated harmful factorsVSStress or pressure

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention merges the advantages of the truncated ideal nozzle (shock-free expansion, low lateral forces during start-up) with the advantages of high outlet pressure nozzles (prevention of flow separation in stationary operation). By combining these two approaches in a single nozzle design, both contradictory requirements are satisfied simultaneously.

Inventive Principle:

Principle #5Merging (Combining)

3Speed

If the nozzle outlet pressure is lowered below ambient pressure to increase gas exit velocity, then thrust is no longer optimal due to flow separation

Engineering Contradiction:

Improvegas exit velocityVSAvoidthrust

Core Design Contradiction:

SpeedVSProductivity

Solution Approach 1:

The wall contour parameters in the second region are specifically designed to maintain higher outlet pressure compared to conventional TIC nozzles. This parameter change ensures that the nozzle operates with optimal thrust efficiency while still achieving high gas exit velocities through proper expansion in the first region.

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

This design effectively minimizes the risk of flow separation and lateral forces, achieving optimal thrust and specific vacuum impulse by smoothly transitioning between the truncated ideal and thrust-optimized nozzle contours, enhancing the nozzle's operational stability and performance.

Implementation Method 1

suppressing the internal shock, so that a flow separation with reattachment is prevented

Methodology Applied

Scientific EffectShock wave: Shock Wave

Implementation Method 2

Flow separations from the wall of the thrust nozzle should be avoided

Methodology Applied

Scientific EffectFlow separation: Flow Separation

Implementation Method 3

These nozzles produce optimal thrust when the ambient pressure is of the same magnitude as the average pressure in the nozzle outlet plane

Methodology Applied

Scientific EffectGas expansion:

Implementation Method 4

Thrust nozzles of rocket engines are formed as convergent-divergent expansion nozzles

Methodology Applied

Scientific EffectDe Laval nozzle effect: De Laval Nozzle

Data Source

PatentEP3144517B1Thrust nozzle

Publication Date: 2020.05.27 ARIANEGRP GMBH

Figure 1~1A
Figure 2
Figure 3

AI summary

A thrust nozzle, in particular thrust nozzle for a rocket engine, with a convergent wall section (1), a throat section (2) and a divergent wall section (3), is characterised in that the divergent wall section (3) has a first region (30) adjacent to the throat section (2), the wall contour (31) of which region corresponds to a truncated ideal nozzle, and that the divergent wall section (3) has a second region (32) facing away from the throat section (2), which region has a wall contour (33) deviating from the first region (30).