Liquid Rocket Combustor Fuel Manifold Design

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Solution Overview

Problem

The existing combustors of liquid rocket engines face challenges in miniaturizing the fuel manifold, achieving improved cooling efficiency, and enhancing structural strength of the nozzle neck, while also being difficult to manufacture using 3D printing due to increased diameter and weight.

Innovation Solution

A combustor design that eliminates the need for a nozzle neck stiffener, featuring a fuel manifold integrated between the fuel manifold outer shell and combustor outer shell, with a downward channel and upward channel configuration that facilitates fuel flow and cooling, allowing for reduced weight and the application of 3D printing technology.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a bell-type expanded nozzle unit with a donut-shaped fuel inlet is used to distribute fuel for regenerative cooling, then cooling coverage is improved, but the diameter and weight of the combustor increase

Engineering Contradiction:

Improvecooling coverageVSAvoidcombustor weight

Core Design Contradiction:

ReliabilityVSWeight of stationary object

Solution Approach 1:

The fuel inlet is repositioned from a horizontal donut-shaped configuration at the expanded nozzle to a vertical downward-facing configuration at the nozzle neck. This dimensional change allows fuel to be distributed along the nozzle neck length rather than radially, reducing the required diameter while maintaining cooling coverage.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

Instead of distributing fuel radially outward from the expanded nozzle as in conventional designs, the invention inverts the approach by distributing fuel vertically downward from the nozzle neck region, changing the direction of fuel flow distribution to achieve compact dimensions.

Inventive Principle:

Principle #13The other way round (Inversion)

2Strength

If a nozzle neck stiffener is added to support the small diameter nozzle neck against vibration, then structural strength is improved, but device complexity and weight increase

Engineering Contradiction:

Improvenozzle neck strengthVSAvoidstructural complexity

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The fuel manifold is merged with the nozzle neck structure, forming an integrated component where the fuel manifold outer shell and combustor outer shell create a stiffened nozzle neck assembly. This eliminates the need for separate nozzle neck stiffeners while providing both fuel distribution and structural support functions.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The nozzle neck region is designed to serve multiple functions simultaneously: it acts as the structural support element, the fuel distribution manifold, and the cooling channel housing. This multi-functionality eliminates the need for separate stiffening components.

Inventive Principle:

Principle #6Universality (Multi-functionality)

3Reliability

If the fuel inlet is positioned at the expanded nozzle unit to provide adequate cooling, then cooling efficiency is improved, but miniaturization becomes difficult

Engineering Contradiction:

Improvecooling efficiencyVSAvoidcombustor volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The fuel distribution approach changes from radial distribution at the expanded nozzle to vertical distribution along the nozzle neck axis. This dimensional shift enables compact combustor volume while maintaining effective cooling through the high-heat flux nozzle neck region.

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 design reduces the weight of the combustor, enables efficient cooling and structural strengthening of the nozzle neck, and allows for cost-effective manufacturing using 3D printing, addressing the limitations of traditional combustor designs.

Implementation Method 1

a regenerative cooling method which reuses the propellant used for cooling the combustion chamber for combustion

Methodology Applied

Scientific EffectRegenerative cooling: Heat Exchanger

Implementation Method 2

a fuel manifold formed between the fuel manifold outer shell and the combustor outer shell, and in which fuel introduced from the fuel inlet flows

Methodology Applied

Scientific EffectFluid distribution:

Implementation Method 3

a nozzle for accelerating the gas produced in the combustor to give direction

Methodology Applied

Scientific EffectDe Laval nozzle effect: De Laval Nozzle

Data Source

PatentUS11598290B2Combustor of liquid rocket engine

Publication Date: 2023.03.07 KOREA AEROSPACE RES INST

AI summary

A combustor of a liquid rocket engine includes a nozzle unit including a regenerative cooling channel, in which the nozzle unit includes a fuel manifold outer shell, a combustor inner shell, and a combustor outer shell having a downward channel inlet, and the combustor includes a fuel inlet connected to a nozzle neck of the nozzle unit, a fuel manifold formed between the fuel manifold outer shell and the combustor outer shell, and in which fuel introduced from the fuel inlet flows, a downward channel connected in communication with the fuel manifold through the downward channel inlet, and extending in a downward direction from an upper portion of the combustor, a diverting manifold provided at a distal end of the nozzle unit and connected in communication with the downward channel, and an upward channel connected in communication with the diverting manifold and extending in an upward direction of the combustor.