Modular Exhaust System Area-Ruled Cross Section

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Solution Overview

Problem

Industrial gas turbine exhaust systems face challenges in balancing aerodynamic efficiency, structural longevity, manufacturing ease, and cost, particularly when adapting to changes in turbine blade designs, leading to inefficient airflow and costly redesigns.

Innovation Solution

A modular drop-in exhaust system with a turbine exhaust case and manifold featuring splined, compound curve tail cones, area-ruled cross sections, and modular stiffening rings that can be easily reconfigured to optimize airflow and structural integrity, allowing for upgrades and replacements without full system redesign.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If an exhaust system is designed to satisfy only aerodynamic objectives with aero-optimized castings/fabrications, then aerodynamic efficiency is improved, but adaptability to accommodate airflow parameter changes deteriorates

Engineering Contradiction:

Improveaerodynamic efficiencyVSAvoidadaptability to airflow parameter changes

Core Design Contradiction:

Loss of energyVSAdaptability or versatility

Solution Approach 1:

The exhaust system is divided into multiple replaceable components including turbine blades, vanes, the exhaust housing, and diffuser sections. This segmentation allows individual components to be optimized for aerodynamic performance while enabling selective replacement or modification of specific parts without redesigning the entire system, thus maintaining adaptability to airflow parameter changes.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The exhaust system incorporates adjustable and replaceable components such as turbine blades and diffuser angles that can be modified based on operating conditions. This dynamic capability allows the system to adapt to varying airflow parameters while maintaining optimal aerodynamic efficiency through component replacement rather than complete redesign.

Inventive Principle:

Principle #15Dynamics

2Reliability

If the entire exhaust system is replaced to repair localized wear, then reliability is improved, but manufacturing cost and resource waste worsen

Engineering Contradiction:

Improvesystem reliabilityVSAvoidmanufacturing cost and material waste

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The exhaust system consists of modular components including turbine blades, vanes, housing sections, and diffuser parts that can be independently replaced. This segmentation enables repair of only the localized worn components rather than the entire system, reducing material waste and manufacturing costs while maintaining system reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The modular component design allows worn or damaged parts to be selectively discarded and replaced, while functional components are retained and reused. This approach recovers valuable materials and reduces manufacturing costs by avoiding unnecessary replacement of intact components.

Inventive Principle:

Principle #34Discarding and recovering

3Ease of manufacture

If sharp angular changes are used in exhaust case sections for ease of manufacture, then ease of manufacture is improved, but aerodynamic performance deteriorates due to flow separation

Engineering Contradiction:

Improveease of fabricating exhaust sectionsVSAvoidenergy loss from flow separation

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The exhaust system employs curved transition sections and rounded diffuser angles instead of sharp angular changes. These curved geometries promote smooth airflow transitions, reduce boundary layer separation, and minimize energy loss while remaining manufacturable through standard fabrication processes for the scale of industrial gas turbine exhaust systems.

Inventive Principle:

Principle #14Spheroidality (Curvature)

4Loss of energy

If more gently curving interior surface constructions are used to reduce flow separation, then aerodynamic efficiency is improved, but manufacturing cost worsens

Engineering Contradiction:

Improveenergy loss from flow separationVSAvoidmanufacturing cost

Core Design Contradiction:

Loss of energyVSEase of manufacture

Solution Approach 1:

The exhaust system incorporates gently curving interior surfaces in critical flow regions such as diffuser sections and transitions, while maintaining simpler geometries in non-critical areas. This selective application of curvature optimizes aerodynamic performance in regions where flow separation would be most harmful, while controlling manufacturing costs by avoiding excessive curvature throughout the entire system.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS9512740B2Industrial gas turbine exhaust system with area ruled exhaust path

Publication Date: 2016.12.06 SIEMENS ENERGY INC

AI summary

An integrated single-piece exhaust system (SPEX) with modular construction that facilitates design changes for enhanced aerodynamics, structural integrity or serviceability. The SPEX defines splined or curved exhaust path surfaces, such as a series of cylindrical and frusto-conical sections that mimic curves. The constructed sections may include: (i) a tail cone assembly fabricated from conical sections that taper downstream to a reduced diameter; or (ii) an area-ruled cross section axially aligned with one or more rows of turbine struts; or both features. Modular inner and outer diameter inlet lips enhance transitional flow between the last row blades and the SPEX, as well as enhance structural integrity. Modular strut collars have large radius profiles between the SPEX annular inner diameter and outer diameter flow surfaces, for enhanced airflow and constant thickness walls for uniform heat transfer and thermal expansion. Scalloped mounting flanges enhance structural integrity and longevity.