Transonic Compressor Stator Vanes Flow Control

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Solution Overview

Problem

Current compressor designs are not suitable for transonic speeds as they experience flow blockage and aerodynamic losses due to high rotor blade speeds, limiting the range of usable speeds and compressor efficiency.

Innovation Solution

A transonic compressor design featuring two or three annular rows of rotor blades with intermediate stator vanes that divert airflow to control relative speeds at the rotor inlet, avoiding blockage by setting specific angle criteria for the stator vanes to manage airflow effectively across the compressor stages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Volume of moving object

If the rotor speed is increased to reduce the number of compression stages, then the compressor becomes more compact and weight is reduced, but flow blockage and aerodynamic losses occur at transonic speeds

Engineering Contradiction:

Improvecompressor sizeVSAvoidflow blockage risk

Core Design Contradiction:

Volume of moving objectVSReliability

Solution Approach 1:

An intermediate stator row is introduced between the first and second rotor rows to act as a mediator that redirects airflow. This intermediate stator modifies the flow angle before it enters the second rotor, preventing flow blockage while allowing the second rotor to be positioned closer to the axis of rotation, thereby reducing compressor size and weight.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The invention changes the flow angle parameter by using the intermediate stator to redirect airflow to angles between 10° and 30° relative to the axial direction. This parameter modification allows the system to operate at higher rotor speeds without flow blockage, enabling compact design with fewer compression stages.

Inventive Principle:

Principle #35Parameter changes

2Volume of moving object

If the second rotor blades are positioned closer to the axis of rotation to reduce compressor size, then the compressor becomes more compact, but flow blockage occurs at the rotor inlet

Engineering Contradiction:

Improvecompressor sizeVSAvoidflow blockage

Core Design Contradiction:

Volume of moving objectVSObject-affected harmful factors

Solution Approach 1:

The intermediate stator row serves as an intermediary element that prepares the airflow for the second rotor. By positioning this stator between the first rotor and second rotor, it redirects the flow at appropriate angles, enabling the second rotor to operate closer to the axis without experiencing flow blockage.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The intermediate stator performs preliminary flow redirection before the airflow enters the second rotor. This preliminary action of adjusting the flow angle ensures that when the airflow reaches the second rotor inlet, it is properly oriented to avoid blockage, allowing compact rotor positioning.

Inventive Principle:

Principle #10Preliminary action

3Weight of moving object

If fewer compression stages are used to reduce weight, then the compressor weight is reduced, but the range of usable rotor speeds is limited

Engineering Contradiction:

Improvecompressor weightVSAvoidusable speed range

Core Design Contradiction:

Weight of moving objectVSAdaptability or versatility

Solution Approach 1:

The intermediate stator row enables the compressor to maintain efficient operation across a wider range of rotor speeds by continuously managing flow angles. This allows fewer compression stages to be used while expanding the usable speed range, as the intermediate stator compensates for varying flow conditions at different speeds.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The system utilizes variable flow angle parameters through the intermediate stator design, allowing adaptation to different rotor speeds. By optimizing the flow redirection angle within the 10°-30° range, the compressor maintains efficiency across a broader speed spectrum despite having fewer stages.

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 allows for a wider range of rotor speeds while preventing flow blockage, ensuring efficient operation with fewer compression stages and maintaining a nominal compression ratio by distributing aerodynamic load effectively across the compressor blades.

Implementation Method 1

the angle of the air flow at the outlet of the intermediate stator vanes... is on average greater than 15° over the height of these blades and is greater than 15°, in various instances greater than 20°, over a radial portion of these stator vanes comprised between 60% and 80% of the height of these blades

Methodology Applied

Scientific EffectFlow redirection through stator vanes:

Data Source

PatentUS11781562B2Transonic turbomachine compressor

Publication Date: 2023.10.10 SAFRAN AERO BOOSTERS SA

AI summary

A transonic compressor of a turbomachine comprising exactly two or exactly three annular rows of rotor blades and respectively exactly one or exactly two annular rows of intermediate stator vanes interposed between two respective rows of rotor blades, wherein the flow velocity relative to the rotor downstream of the intermediate stator vanes is less than or equal to a Mach number of 0.9 over a radial portion of the blades extending over the radially inner 40% of the blades, and less than or equal to a Mach number of 1 over a radial portion extending over the radially inner 80% of the blades, and less than or equal to a Mach number of 1.05 over a radial portion extending over the radially outer 20% of the blades.