Gas Turbine Transition Duct Cooling via Bent Channels
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Solution Overview
Problem
Existing transition ducts in gas turbine plants face inefficiencies in cooling, particularly at the downstream portion connected to the turbine section, leading to inadequate heat management and reduced efficiency due to the need for large airflow diversion from the compressor.
Innovation Solution
A transition duct design featuring a tubular body with convective cooling channels that include a bent portion to enhance turbulence and heat transfer, accelerating the cooling flow and optimizing cooling at high heat load areas, including the use of fins to promote secondary vortices and additional inlets to fine-tune airflow and heat transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a large airflow is subtracted from the compressor for cooling the transition duct, then the cooling effect is improved, but the efficiency of the gas turbine deteriorates
Solution Approach 1:
The patent applies local quality by creating different flow directions within the cooling channel: a first flow direction in the inlet portion and a second flow direction (opposite to the first) in the main portion, achieved through a bent portion. This localized flow reversal optimizes cooling at the downstream end where heat load is highest, while maintaining better overall system efficiency by reducing the total airflow needed from the compressor.
Solution Approach 2:
The patent uses curvature by introducing a bent portion in the cooling channel that deflects the cooling fluid flow in a different direction. This curved path creates turbulence and enhances heat transfer, particularly at the downstream portion of the transition duct, improving cooling effectiveness without requiring proportionally larger airflow subtraction.
2Device complexity
If conventional cooling channels are used, then the structure is simple, but the cooling of the downstream portion of the transition duct is inadequate
Solution Approach 1:
The patent addresses inadequate cooling at the downstream portion by implementing local quality through a bent portion that creates a second flow direction opposite to the main flow. This localized flow reversal concentrates cooling effectiveness at the downstream end where heat load is highest, while the rest of the channel maintains a simpler straight configuration.
Solution Approach 2:
The bent portion introducing flow reversal in the opposite direction represents the application of curvature principle. This curved section enhances turbulence and heat transfer specifically at the downstream portion of the transition duct, improving cooling adequacy without significantly complicating the overall channel structure.
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 optimized cooling design effectively reduces heat-related damage and increases the efficiency of the gas turbine by improving heat transfer and maintaining performance without significant airflow loss from the compressor.
Implementation Method 1
In the bent portion, in fact, a lot of turbulence is introduced and the heat transfer increases
Implementation Method 2
at least one first convective cooling channel arranged between the inner wall and the outer wall
Implementation Method 3
the radial height of at least one section of the inlet portion of the first convective cooling channel decreases along the first direction. In this way, the cooling flow is accelerated and provides additional heat transfer increase
Data Source
Figure 1~2
Figure 3~4
Figure 5~7
AI summary
A gas turbine transition duct (10) comprising: a tubular body (25) having an upstream end (28) configured to be coupled to a combustor (9) and a downstream end (20) configured to be coupled to a turbine (5); the tubular body (25) comprising: an outer wall (30); an inner wall (31) defining a transition channel (33); at least one first convective cooling channel (40) arranged between the inner wall (31) and the outer wall (30) having at least one first inlet (46; 50) made in the outer wall (30) between the upstream end (28) and the downstream end (29); the first convective cooling channel (40) comprising at least one inlet portion (43; 48) comprising the first inlet (46; 50), a main portion (44) and at least one bent portion (45; 49) arranged between the inlet portion (43; 48) and the main portion (44).