Steam Turbine Exhaust Chamber Segmentation for Diffuser Optimization

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Solution Overview

Problem

Standardizing the outer casing of a steam turbine while optimizing the diffuser shape is challenging due to the integration of the bearing cone, which requires redesigning the casing to achieve an appropriate diffuser shape.

Innovation Solution

The steam turbine exhaust chamber design includes an outer casing with an end wall and an extension part, featuring a first flow guide forming the upstream region of the diffuser surface and a second flow guide forming the downstream region, both of which can be individually optimized without altering the outer casing structure, along with connection ribs to enhance rigidity and prevent steam intrusion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the bearing cone is integrated into the outer casing to standardize the structure, then the outer casing can be standardized and manufactured efficiently, but the diffuser shape cannot be optimized individually for each steam turbine

Engineering Contradiction:

Improvestandardization of outer casingVSAvoidoptimization of diffuser shape

Core Design Contradiction:

Ease of manufactureVSAdaptability or versatility

Solution Approach 1:

The exhaust chamber is divided into two independent parts: the standardized outer casing and the detachable flow guides. The flow guides (first and second flow guides) can be separately designed and optimized for each steam turbine application while the outer casing remains standardized. This segmentation allows the diffuser shape to be customized without affecting the standardized casing structure.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flow guides are extracted as separate components from the outer casing. Instead of integrating the diffuser shape into the casing, the flow guides are taken out as independent parts that can be attached to or removed from the standardized outer casing, enabling individual optimization of the diffuser shape for each application.

Inventive Principle:

Principle #2Taking out (Extraction)

2Loss of energy

If the diffuser shape is optimized for each steam turbine by redesigning the outer casing, then the exhaust loss is reduced, but the manufacturing cost and complexity increase

Engineering Contradiction:

Improveturbine exhaust lossVSAvoidredesign of outer casing

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The exhaust chamber is segmented into a standardized outer casing and detachable flow guides. This allows the diffuser shape to be optimized for each steam turbine by designing custom flow guides while maintaining a standardized outer casing, thereby reducing exhaust loss without increasing overall device complexity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The flow guides are designed to be detachable and replaceable components. This dynamic configuration allows the diffuser shape to be adapted to different steam turbine requirements by simply replacing the flow guides, rather than redesigning the entire outer casing structure.

Inventive Principle:

Principle #15Dynamics

3Adaptability or versatility

If the flow guides are fixed to the extension part of the outer casing, then the diffuser shape can be optimized, but the rigidity and structural stability may be compromised

Engineering Contradiction:

Improveoptimization of diffuser shapeVSAvoidrigidity of diffuser structure

Core Design Contradiction:

Adaptability or versatilityVSStrength

Solution Approach 1:

The flow guides are extracted as separate components that attach to the extension part of the outer casing. This allows the diffuser shape to be optimized while maintaining structural integrity, as the flow guides are attached rather than integrated, preserving the rigidity of the overall structure.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The extension part of the outer casing serves as an intermediary structure that provides a mounting interface for the flow guides. This intermediary design allows the flow guides to be securely attached while maintaining the structural stability and rigidity of the overall exhaust chamber.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS11536162B2Exhaust chamber of steam turbine, steam turbine, and steam turbine replacement method

Publication Date: 2022.12.27 MITSUBISHI HEAVY IND LTD

AI summary

An exhaust chamber of a steam turbine according to an embodiment includes an outer casing which includes an end wall part in an axial direction and an extension part extending upward in the axial direction from the end wall part, a first flow guide formed into an annular shape, the first flow guide forming an upstream region of a diffuser surface in a hub-side flow guide and being fixed to an upstream end portion of the extension part on a radially inner side of the diffuser surface, and a second flow guide formed into an annular shape, the second flow guide forming a downstream region of the diffuser surface at a position downstream of the first flow guide and on a radially outer side of the extension part, and being fixed to the extension part.