Steam Turbine Flow Shield for Thermal Gradient Reduction

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Solution Overview

Problem

Compact steam turbines face significant mechanical and thermal loading issues due to temperature gradients and limited installation space, leading to high maintenance costs and reduced efficiency, particularly in regions with reheating mechanisms.

Innovation Solution

A steam turbine design featuring a flow shield that deflects steam flow to reduce temperature gradients at the turbine housing, using a partially spaced flow shield with openings to the flow space to maintain steam communication and reduce thermal loading, while allowing uniformly dimensioned fastening elements for housing parts, thus improving efficiency and loadability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a flow shield is used to reduce temperature gradients at the turbine housing, then thermal loading on the housing is reduced, but the steam flow path is obstructed

Engineering Contradiction:

Improvetemperature gradient at turbine housingVSAvoidsteam mass flow

Core Design Contradiction:

TemperatureVSProductivity

Solution Approach 1:

The flow shield is positioned only at specific locations where temperature gradients are most severe, rather than covering the entire turbine housing. This localized approach reduces thermal loading at critical areas while maintaining steam flow paths in other regions, thus balancing thermal protection with productivity

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The flow shield provides partial protection rather than complete coverage, allowing some steam to pass through while still reducing the temperature gradient sufficiently to protect the housing from excessive thermal loading

Inventive Principle:

Principle #16Partial or excessive action

2Volume of stationary object

If the turbine housing is made compact to reduce installation space, then the installation space is reduced, but the mechanical and thermal loading on the housing increases

Engineering Contradiction:

Improveinstallation spaceVSAvoidmechanical and thermal loading capacity

Core Design Contradiction:

Volume of stationary objectVSStrength

Solution Approach 1:

The flow shield changes the thermal parameters in the housing by reducing temperature gradients, which directly reduces thermal stress on the housing structure. This allows the housing to withstand higher mechanical and thermal loads even in a compact configuration

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The flow shield acts as a protective element that cushions the housing against thermal loading before the full thermal stress can develop, preventing excessive temperature gradients from causing structural damage

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Productivity

If reheating devices are added between turbine sections to improve efficiency, then efficiency is improved, but temperature fluctuations and thermal loading on the housing increase

Engineering Contradiction:

Improveturbine efficiencyVSAvoidtemperature fluctuations along turbine longitudinal axis

Core Design Contradiction:

ProductivityVSTemperature

Solution Approach 1:

The flow shield serves as an intermediary element between the steam flow and the turbine housing, absorbing and redistributing thermal energy to reduce temperature fluctuations caused by reheating operations

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The flow shield converts the harmful effect of temperature fluctuations into a beneficial temperature distribution pattern, using the thermal energy from reheating to create more uniform housing temperatures rather than extreme gradients

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

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 solution effectively reduces thermal loading on the turbine housing, minimizing stress at parting lines and allowing increased steam mass flow, thereby enhancing the efficiency and load capacity of compact steam turbines without increasing overall size or production complexity.

Implementation Method 1

a flow shield (7) which is arranged on a side of the housing wall (5) facing the flow space (3), the flow shield (7) shielding a wall portion (5a) of the housing wall (5) from a flow in the flow space (3)

Methodology Applied

Scientific EffectFlow deflection:

Implementation Method 2

An intermediate space (8) is formed between the flow shield (7) and the wall portion (5a) of the housing wall (5), wherein, in at least one region, the intermediate space (8) has an opening (9) to the flow space (3)

Methodology Applied

Scientific EffectFluid communication:

Data Source

PatentUS11274572B2Steam turbine with flow shield

Publication Date: 2022.03.15 SIEMENS ENERGY GLOBAL GMBH & CO KG

AI summary

A steam turbine having a turbine housing which has a plurality of turbine housing parts and surrounds a flow space along a turbine longitudinal axis, the turbine housing having a housing wall, a join being formed between two adjacent turbine housing parts. On a side of the housing wall facing the flow space, there is at least one flow shield which shields a wall section of the housing wall from a flow in the flow space. An interstice is formed between the flow shield and the wall section of the housing wall. The interstice has, at least in one region, an opening to the flow space, a fluid-communicating connection of the interstice to the flow space being formed via the opening.