Multi-Spool CO2 Power Architecture for Feasible Aircraft Generators

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Current generator design faces challenges in accommodating the high rotational speeds required for CO2 compressors and turbines, making it difficult to achieve the desired power level and pressure ratio with a single generator.

Innovation Solution

A multi-spool, multi-shaft CO2 power system is implemented, comprising multiple interconnected compressors and turbines, each connected via separate shafts, with generators driven by these shafts to distribute power generation across multiple units, optimizing pressure ratios and reducing rotational speed requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If a single generator is used to operate at the high speed of CO2 machines, then power generation is achieved, but the generator design becomes extremely difficult and infeasible with current technology

Engineering Contradiction:
Improvepower generationVSAvoidgenerator design feasibility
Core Design Contradiction:
PowerVSEase of manufacture

Solution Approach 1:

The patent divides the single generator system into multiple generators (first generator and second generator) connected to separate shafts. Each generator operates at a lower rotational speed and handles a portion of the total power generation, making the design feasible with current technology while collectively achieving the desired power level.

Inventive Principle:
Principle #1Segmentation

2Power

If a single-spool compressor/turbine system is used, then the system structure is simple, but it cannot operate at the required pressure ratio and flow rates to produce the desired power level

Engineering Contradiction:
Improvepower levelVSAvoidsystem structure
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent implements a multi-spool system with separate first and second shafts, each driving a compressor and turbine pair. This segmentation allows each spool to operate at optimized pressure ratios and flow rates, collectively achieving the required power level while maintaining manageable complexity through modular architecture.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a single-spool one-dimensional system to a multi-spool multi-dimensional system. By adding the dimension of multiple independent shafts and turbines, the system can simultaneously handle different pressure ratios and flow rates, enabling achievement of the desired power level that is infeasible in a single-spool configuration.

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

3Ease of manufacture

If the rotational speed of CO2 compressors and turbines is reduced, then generator design becomes more feasible, but the power generation capability decreases

Engineering Contradiction:
Improvegenerator designVSAvoidpower generation capability
Core Design Contradiction:
Ease of manufactureVSPower

Solution Approach 1:

The patent segments the power generation task across multiple generators operating at reduced rotational speeds. Each generator is designed to be feasible at lower speeds, and their combined output maintains the required total power generation capability, thus resolving the contradiction between manufacturability and power capability.

Inventive Principle:
Principle #1Segmentation

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 system effectively generates the desired power level without the need for a single large generator, feasible at reduced rotational speeds, and achieves optimal pressure ratios through staged compression and expansion across multiple compressors and turbines.

Implementation Method 1

a CO2 recuperator including a first inlet and a first outlet, and a second inlet and a second outlet, the first inlet being fluidically connected to the third compressor and the second inlet being fluidically connected to the first turbine

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

an exhaust heat exchanger including an inlet portion fluidically connected to the first outlet of the CO2 recuperator and an outlet portion fluidically connected to the third turbine

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 3

a first ram air heat exchanger including a first heat exchanger inlet fluidically connected to the second outlet of the CO2 recuperator and a first heat exchanger outlet fluidically connected to the first compressor

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4257813B1Multi-spool co2 aircraft power system for operating multiple generators
Publication Date: 2025.12.31 HAMILTON SUNDSTRAND CORP
  • EP4257813B1 patent drawingFigure 1
  • EP4257813B1 patent drawingFigure 2
  • EP4257813B1 patent drawingFigure 3

AI summary

A CO2 bottoming cycle (40) system includes a first compressor (46) operatively connected to a first turbine (48) through a first shaft (50). A first generator is operatively connected to the first shaft. A second compressor (66) is fluidically connected to the first compressor (46). The second compressor (66) is operatively connected to a second turbine (68) through a second shaft (70). A second generator is operatively connected to the second shaft. The first turbine (48) is fluidically connected to the second turbine (68).