Precooled Turbine Inlet and Variable Nozzle for High-Speed Flight

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Solution Overview

Problem

Conventional flight vehicle designs face challenges in operating at high speeds due to material temperature limits and inefficient nozzle designs, which limit the top operating speed and range of the vehicle.

Innovation Solution

A turbine engine with integrated heat exchangers and a movable nozzle assembly that includes a cowl and plug system, allowing for targeted cooling and adjustable thrust characteristics to maintain optimal operating conditions across a range of speeds.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the engine operates at high speeds (Mach 3+), then propulsion performance is improved, but localized temperatures reach or exceed material temperature limits

Engineering Contradiction:
Improveflight speedVSAvoidlocalized temperature
Core Design Contradiction:
SpeedVSTemperature

Solution Approach 1:

The inlet precooler is positioned upstream of the turbine engine inlet to cool the airflow before it enters the engine. This preliminary cooling action prevents the air from reaching excessive temperatures during high-speed operation, allowing the engine to maintain full power without exceeding material temperature limits.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The inlet precooler acts as an intermediary component between the high-speed airflow and the turbine engine. It mediates the temperature of the incoming air, reducing it to acceptable levels before the air enters the compressor section, thereby enabling sustained high-speed operation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Temperature

If the engine is throttled back to avoid exceeding material temperature limits, then temperature constraints are satisfied, but the engine no longer accelerates the flight vehicle, thereby limiting top operating speed

Engineering Contradiction:
Improvematerial temperature limitVSAvoidtop operating speed
Core Design Contradiction:
TemperatureVSSpeed

Solution Approach 1:

By cooling the airflow preliminarily in the inlet precooler, the system eliminates the need for throttling back the engine. The engine can operate at full power settings while the precooler ensures that the compressed air temperature remains within material limits, thereby achieving both temperature control and maximum speed capability.

Inventive Principle:
Principle #10Preliminary action

3Speed

If a nozzle is configured for speeds greater than Mach 3, then high-speed performance is improved, but the nozzle induces over-expansion drag at lower speeds

Engineering Contradiction:
Improvehigh-speed performanceVSAvoidover-expansion drag
Core Design Contradiction:
SpeedVSObject-affected harmful factors

Solution Approach 1:

The nozzle assembly incorporates movable components including a cowl and plug that can adjust the nozzle geometry. This dynamic configuration allows the nozzle to be optimized for different speed regimes, reducing over-expansion drag at lower speeds while maintaining high-speed performance capability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The nozzle system changes geometric parameters (area ratio, expansion angle) based on operating conditions. By adjusting these parameters, the nozzle maintains optimal performance across a range of speeds, avoiding the over-expansion drag that would occur with a fixed high-speed optimized nozzle at lower speeds.

Inventive Principle:
Principle #35Parameter changes

4Use of energy by moving object

If a nozzle is configured for high speeds, then propulsive efficiency at high speeds is improved, but the nozzle fails to provide propulsive efficiency across a range of operating speeds

Engineering Contradiction:
Improvepropulsive efficiencyVSAvoidoperating range
Core Design Contradiction:
Use of energy by moving objectVSAdaptability or versatility

Solution Approach 1:

The movable cowl and plug in the nozzle assembly enable dynamic adjustment of the nozzle geometry to match different operating speeds. This adaptability ensures that the nozzle maintains high propulsive efficiency across the full operating range, from lower speeds to hypersonic speeds greater than Mach 5.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The nozzle assembly is designed to perform multiple functions across different speed regimes through its adjustable geometry. The same nozzle structure can be configured for efficient operation at various speeds, eliminating the need for separate nozzles for different flight regimes and achieving universal propulsive efficiency.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 system enables flight vehicles to operate at higher speeds by preventing component overheating and optimizing nozzle efficiency, thereby expanding the operating range and maintaining propulsion performance.

Implementation Method 1

an inlet precooler positioned at least partially within the inlet section of the ducting assembly and upstream of the turbine engine inlet, the bypass duct, or both for cooling an airflow provided through the inlet section of the ducting assembly to the turbine engine inlet, the bypass duct, or both

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Implementation Method 2

a heat exchanger arrangement 103 arranged downstream of the air intake arrangement, configured to cool the air

Methodology Applied
Scientific EffectHeat exchange: Heat Exchanger

Data Source

PatentEP4015796B1Systems and methods for expanding an operating speed range of a high speed flight vehicle
Publication Date: 2025.12.31 THE BOEING CO
  • EP4015796B1 patent drawingFigure 1
  • EP4015796B1 patent drawingFigure 2~6
  • EP4015796B1 patent drawingFigure 7~8

AI summary

Systems and methods for expanding an operating speed range of a high speed flight vehicle (102) include providing a turbine engine (100) with an inlet air duct (112), and positioning a heat exchanger (140) in the inlet air duct (112) to cool at least a portion of duct air flow (118) associated with an engine core (122). Additionally or alternatively, a nozzle assembly (200) includes a cowl (210) fluidly communicating with the turbine engine (100) and having a cowl internal surface (216) defining a cowl orifice (218), and a plug (230) defines a primary thrust surface (232). The plug (230) is supported relative to the cowl (210) so that a portion of the primary thrust surface (232) is disposed within the cowl orifice (218) to define a throat (242) therebetween. An actuator (248) is coupled to at least one of the cowl (210) or the plug (230), and is configured to generate relative movement between the cowl (210) and the plug (230), thereby to modify the throat (242).