Steam Turbine Casing Noise Reduction via Segmented Insulation

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Solution Overview

Problem

Steam turbines experience increased noise on the low-pressure side due to thinner casings and longer blades, which existing noise reduction methods, such as uniform heat insulation, fail to adequately address, leading to inefficiencies and larger apparatus sizes.

Innovation Solution

A steam turbine design featuring a thermal insulation member on the high-pressure side and a soundproof cover with silencing porous plates and sound absorbing porous plates on the low-pressure side, utilizing spaced configurations to absorb and attenuate noise, while maintaining a compact size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a uniform heat insulating layer is provided on the casing, then thermal insulation is improved, but noise reduction on the low-pressure side is insufficient

Engineering Contradiction:

Improvethermal insulationVSAvoidnoise on low-pressure side

Core Design Contradiction:

TemperatureVSObject-affected harmful factors

Solution Approach 1:

The casing is divided into high-pressure side region and low-pressure side region, with different noise control measures applied to each region. The low-pressure side is segmented to receive dedicated soundproof covers while the high-pressure side uses thermal insulation members that also provide noise reduction.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the casing are given different properties: the low-pressure side region is equipped with soundproof covers having sound absorbing materials and spaced configurations for noise reduction, while the high-pressure side region uses thermal insulation members. This local differentiation addresses the specific noise problem on the low-pressure side without compromising thermal insulation elsewhere.

Inventive Principle:

Principle #3Local quality

2Object-affected harmful factors

If an outer garment is formed to cover the entire steam turbine, then noise is reduced, but the apparatus size becomes large due to maintenance space requirements

Engineering Contradiction:

ImprovenoiseVSAvoidapparatus size

Core Design Contradiction:

Object-affected harmful factorsVSVolume of stationary object

Solution Approach 1:

The noise control function is extracted from a comprehensive outer garment approach and applied locally only where needed - specifically on the low-pressure side region where noise is most problematic. This eliminates the need for a full-coverage outer garment that would require large maintenance spaces, while still achieving effective noise reduction at the critical location.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

Instead of applying noise control measures to the entire steam turbine (excessive action), the invention applies soundproof covers only to the low-pressure side region where noise is most problematic (partial action). This partial application achieves sufficient noise reduction without the space penalty of a complete outer garment.

Inventive Principle:

Principle #16Partial or excessive action

3Ease of manufacture

If the casing plate thickness is reduced on the low-pressure side, then manufacturing cost is reduced, but noise propagation increases

Engineering Contradiction:

Improvemanufacturing costVSAvoidnoise propagation

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

Sound absorbing materials are introduced as intermediary elements between the thin-walled low-pressure side casing and the external environment. These materials (such as foamed plastics, fibrous materials, or porous ceramics) block noise propagation paths that would otherwise easily transmit through the thin casing walls, enabling cost-effective thin-walled construction without sacrificing noise control.

Inventive Principle:

Principle #24Intermediary (Mediator)

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

Effectively reduces noise on the low-pressure side by absorbing sound waves and minimizing heat diffusion on the high-pressure side, resulting in a more compact and cost-effective steam turbine.

Implementation Method 1

a soundproof cover which covers the casing in the low-pressure side region out of the high-pressure side region and the low-pressure side region via a space between the outer surface of the casing and the soundproof cover

Methodology Applied

Scientific EffectAcoustic absorption: Acoustic Absorption

Implementation Method 2

a thermal insulation member which is provided to be in contact with an outer surface of the casing in a high-pressure side region out of the high-pressure side region and a low-pressure side region in which pressure of the steam is different from each other of the casing in the axial direction

Methodology Applied

Scientific EffectThermal insulation: Thermal Insulation

Data Source

PatentUS11401888B2Steam turbine and construction method of steam turbine

Publication Date: 2022.08.02 MITSUBISHI HEAVY INDUSTIES COMPRESSOR CORP

AI summary

A steam turbine 1 includes a turbine body 11 which includes a rotor 5 which is configured to rotate around an axis Ac, and a casing 6 which covers the rotor 5 to form a flow path through which steam flows in an axis Ac direction, together with the rotor 5, a thermal insulation member 12 which is provided to be in contact with an outer surface of the casing 6 in a high-pressure side region 61 out of the high-pressure side region 61 and a low-pressure side region 62 of the steam in the axis Ac direction of the casing 6, and a soundproof cover 13 which covers the low-pressure side region 62 out of the high-pressure side region 61 and the low-pressure side region 62 via a space between the outer surface of the casing 6 and the soundproof cover 13.