Rounded Cooling Jacket Edges for Gas Turbine Combustion Chambers
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Solution Overview
Problem
The existing configuration of inner cooling jackets in gas turbines is susceptible to distance tolerances and irregularities, leading to suboptimal flow conditions and cooling efficiency, particularly in the annular combustion chambers where conventional convection cooling is used due to space constraints and seal requirements.
Innovation Solution
The cooling jackets are designed with rounded entry and exit edges to improve airflow, and are composed of segmented elements with distributed fastening and overlapping features to enhance cooling air flow and heat transfer, including bell-shaped leading edges and raised side edges to adapt to the shape of the shells, reducing flow losses and increasing heat transfer efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional convection cooling is used in annular combustion chambers, then space constraints and seal requirements are satisfied, but cooling efficiency is suboptimal due to distance tolerances and irregularities
Solution Approach 1:
The cooling air inlet edge is designed with a rounded shape instead of a sharp edge. This curvature prevents flow separation and turbulence at the inlet, ensuring smooth airflow into the cooling channel. The rounded geometry compensates for manufacturing tolerances by maintaining consistent flow conditions even when distance tolerances vary, thereby improving cooling efficiency without requiring extremely precise manufacturing.
Solution Approach 2:
The invention modifies the geometric parameters of the cooling channel inlet by introducing a rounded edge with a specific radius. This parameter change optimizes the flow conditions by reducing flow separation and turbulence. The rounded inlet geometry creates more favorable pressure gradients and flow patterns, enhancing heat transfer efficiency while being tolerant to variations in manufacturing precision.
2Ease of manufacture
If cooling jackets are designed as single pieces, then assembly is simpler, but adaptation to shell shapes and flow optimization are limited
Solution Approach 1:
The cooling jacket is divided into multiple segments rather than being a single piece. Each segment can be independently manufactured and then assembled together using connection elements. This segmentation allows each segment to be optimized for specific flow conditions and to adapt to the complex geometry of the combustion chamber shells. The modular design maintains ease of assembly while significantly improving adaptability to shell shapes and flow optimization.
Solution Approach 2:
The segmented design allows the cooling jacket to dynamically adapt to thermal expansion and mechanical deformations of the combustion chamber shells during operation. Each segment can move independently to accommodate changes in the shell geometry, maintaining optimal flow conditions and sealing contact throughout the operational range.
3Temperature
If cooling channel height is reduced to increase heat transfer, then convective cooling intensity increases, but flow losses and turbulence increase
Solution Approach 1:
The rounded inlet edge creates smooth flow curvature that prevents flow separation even in narrow cooling channels. This curved geometry guides the cooling air smoothly into the channel, reducing turbulence and flow losses. The rounded inlet maintains laminar or controlled turbulent flow patterns that enhance heat transfer while minimizing energy losses, allowing the use of smaller channel heights without excessive flow losses.
Solution Approach 2:
By changing the inlet geometry parameter from a sharp edge to a rounded edge with optimized radius, the invention achieves better flow characteristics in narrow channels. The rounded inlet creates favorable velocity profiles and pressure distributions that reduce flow separation and recirculation zones, thereby reducing flow losses while maintaining high heat transfer intensity in compact channel configurations.
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 improves cooling air flow conditions, reduces material temperature, and enhances heat transfer efficiency, leading to more effective convective cooling and reduced operational costs by minimizing turbulence and flow losses, thus improving the overall performance of the gas turbine combustion chamber.
Implementation Method 1
The at least one cooling jacket has a rounded entry edge bent outwards on the side on which the cooling air enters the cooling channel in order to improve the inflow conditions
Implementation Method 2
the shells 23, 33 are convectively cooled
Implementation Method 3
enhances heat transfer efficiency, leading to more effective convective cooling
Data Source
Figure 1
Figure 2~2a
Figure 3
AI summary
The machine has an annular combustion chamber externally defined by an outer shell and an inner shell (33), where a hot gas stream flows through the combustion chamber in an axial direction. An annular cooling channel (32) with a concentric inner cooling jacket (31) is provided at an outer side of the inner shell, where a cooling air flows through the channel in a direction opposite to the hot gas stream. An outwardly curved rounded inlet edge (37) is provided on a side of the cooling jacket, where the cooling air enters into the cooling channel through the side of the jacket.