Segmented Turbine Nozzle Box for Partial Arc Steam Distribution

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Solution Overview

Problem

Conventional turbine nozzle boxes experience reduced efficiency during partial arc operations due to the formation of dead arc zones, which occur when steam is not evenly distributed across the turbine regions, leading to blocked passages and inefficient steam flow.

Innovation Solution

A turbine nozzle box design featuring four segment blocks installed at a 90-degree arc angle at the inlet end, dividing the inlet into four portions, and an overall arc operation at the outlet end, allowing for improved steam distribution and reduced dead arc zones, with each segment block having a nozzle frame, extension parts, and a passage for streamlined fluid flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the turbine nozzle box is uniformly divided into many sections for partial arc operation, then the structure can support partial operation modes, but gas may not be introduced into a partial section due to full blocking of passages, leading to formation of dead arc zones and reduced turbine efficiency

Engineering Contradiction:
Improvepartial arc operation capabilityVSAvoidturbine efficiency
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The nozzle box is divided into multiple nozzle units, each unit comprising several nozzles arranged in an arc. This segmentation allows selective operation of individual nozzle units for partial arc operations while maintaining proper steam flow distribution. Each nozzle unit can be independently controlled to prevent dead arc zones and maintain turbine efficiency during partial load operations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the nozzle box are designed with different characteristics - the nozzle units are arranged with varying arc angles and positions to optimize steam distribution for both full arc and partial arc operations. This local differentiation ensures that during partial arc operation, steam is properly directed to active sections while preventing dead arc zone formation.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If conventional turbine nozzle boxes use bolts or welding to couple parts, then the structure can be assembled, but the complexity of assembly and potential for leakage increase

Engineering Contradiction:
Improveassembly capabilityVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The nozzle units are designed as integrated components that are coupled to the nozzle box body through simple flange connections rather than requiring complex bolt assemblies or welding procedures. This merging of design simplifies the assembly process, reduces the number of fastening elements required, and minimizes potential leakage points while maintaining structural integrity.

Inventive Principle:
Principle #5Merging (Combining)

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 enhances the overall efficiency of the turbine by ensuring uniform steam distribution and reducing dead arc zones, thereby improving fluid flow and electricity generation capacity during partial arc operations.

Implementation Method 1

An impulse steam turbine allows the thermal energy of steam to perform more expansion work using each turbine nozzle

Methodology Applied
Scientific EffectSteam expansion work: Heat Engine

Implementation Method 2

it is accelerated about the rotary axis of a rotor through nozzles located on the outlet plane of the nozzle box

Methodology Applied
Scientific EffectFluid flow acceleration: De Laval Nozzle

Data Source

PatentEP3085898B1Turbine nozzle box
Publication Date: 2019.10.30 DOOSAN HEAVY IND & CONSTR CO LTD
  • EP3085898B1 patent drawingFigure 1
  • EP3085898B1 patent drawingFigure 2
  • EP3085898B1 patent drawingFigure 3

AI summary

A turbine nozzle box (1) includes an annular outer ring plate (100), an annular nozzle unit (200), and an annular inner ring plate (300). The annular outer ring plate (100) is operable to be disposed in a turbine such that an outer peripheral surface thereof is adjacent to an inner peripheral surface of an inner casing (10) of the turbine. The annular nozzle unit (200) is disposed adjacent to an inner peripheral surface of the outer ring plate (100). The annular inner ring plate (300) is disposed such that an outer peripheral surface thereof is adjacent to an inner peripheral surface of the nozzle unit (200). The nozzle unit (200) includes a plurality of segment blocks (210) circumferentially installed at an arc angle. The segment blocks (210) are disposed at an inlet end (202) of a first-stage nozzle unit, and an outlet end (203) of the first-stage nozzle unit is open.