Axial Compressor Injection Device Using Bleed Air Slots

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Solution Overview

Problem

Existing axial compressors face challenges in efficiently injecting fluids into the gas flow without requiring extensive and costly modifications to the compressor structure, often leading to sealing issues and mechanical and thermal strength concerns.

Innovation Solution

The axial compressor design incorporates annular bleed air chambers with bleed air slots that house nozzles for fluid injection, allowing for a simple and cost-effective arrangement where the nozzles are distributed over the circumference, and the casing is split for easier assembly and disassembly, using flexible connecting hoses and flanges for fluid supply, enabling efficient fluid injection with minimal casing machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If nozzles are accommodated directly in a bore in a casing wall, then fluid injection is achieved, but sealing issues and mechanical strength problems occur

Engineering Contradiction:

Improvenozzle arrangement simplicityVSAvoidsealing and mechanical strength

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The patent introduces an intermediary structure (injection device with nozzle mounted on support element within bleed air chamber) between the external fluid supply and the gas passage. This mediator allows fluid injection while avoiding direct penetration of the casing wall, thereby resolving sealing and mechanical strength issues.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The injection device is nested within the existing bleed air chamber structure. The nozzle is positioned inside the bleed air chamber which itself is contained within the casing, allowing fluid injection into the gas passage without compromising the integrity of the outer casing wall.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Adaptability or versatility

If extensive machining of the casing is performed to accommodate nozzles, then fluid injection capability is achieved, but manufacturing cost and complexity increase

Engineering Contradiction:

Improvefluid injection capabilityVSAvoidcasing machining requirements

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bleed air chamber, which already serves the function of cooling the rotor shaft, is repurposed to also accommodate the fluid injection device. This multi-functional use of existing space avoids the need for additional casings or extensive machining, thereby reducing manufacturing complexity while maintaining injection capability.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The existing bleed air chamber structure serves dual purposes: it provides cooling air to the rotor shaft and simultaneously houses the injection device for fluid injection. The system utilizes its own existing infrastructure rather than requiring separate dedicated structures for each function.

Inventive Principle:

Principle #25Self-service

3Productivity

If nozzles are arranged in a distributed manner on the trailing edge of a stator blade, then fluid injection into the gas flow is achieved, but expensive internal casing machining is required

Engineering Contradiction:

Improvefluid mixing efficiencyVSAvoidcasing machining cost

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

Instead of mounting nozzles on the trailing edge of stator blades (as proposed in prior art), the patent inverts the approach by positioning nozzles within the bleed air chamber that feeds into the gas passage. This reversal achieves fluid injection while avoiding the need for expensive internal casing machining and stator blade modifications.

Inventive Principle:

Principle #13The other way round (Inversion)

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 effective fluid injection into the gas flow with reduced casing machining, improved sealing, and enhanced mechanical stability, while maintaining the compressor's structural integrity and flexibility to adapt to thermodynamic specifications.

Implementation Method 1

at least one injection device for injecting a fluid, the injection device having at least one nozzle for injecting the fluid into the gas passage slot

Methodology Applied

Scientific EffectFluid injection: Jet

Data Source

PatentUS9004853B2Axial compressor with an injection device for injecting a fluid

Publication Date: 2015.04.14 ANSALDO ENERGIA SWITZERLAND AG

AI summary

An axial compressor is disclosed for compressing air, such as for a gas turbine. The axial compressor can include a rotor, having a multiplicity of rotor blades, and rotor casing. The casing and rotor can form an annular gas passage. Outside the gas passage an annular and concentric bleed air chamber, can include at least one bleed air slot in functional communication with the gas passage. At least one injection device having at least one nozzle which can inject the fluid into the gas passage via the bleed air slot.