Gas Turbine Combustor Air Extraction Port Design
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Solution Overview
Problem
In gas turbine engines, extracting air from the combustor for cooling purposes can disrupt the uniformity of the pressure field, which is undesirable.
Innovation Solution
The air extraction ports are designed with a specific ratio of inlet to final area and passage length, incorporating bends with radii proportional to the inlet hydraulic diameter, to minimize pressure perturbations and ensure a smooth airflow contraction, maintaining a local Mach number range that prevents turbulence.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If air is extracted from the combustor for cooling turbine components, then cooling effectiveness is improved, but pressure field uniformity deteriorates
Solution Approach 1:
The air extraction port is designed with a specific geometric configuration where the inlet area is greater than the final area, creating a contraction passage. This local geometric quality variation optimizes the flow characteristics at the extraction point, allowing effective cooling air extraction while minimizing disruption to the overall pressure field uniformity in the combustor
Solution Approach 2:
The invention specifies particular parameter ranges for the extraction port: the ratio of inlet area to final area is between 1.0 and 1.6, and the passage length to inlet hydraulic diameter ratio is between 4 and 8. These parameter changes optimize the balance between extraction efficiency and pressure field preservation
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 effectively extracts cooling airflow while maintaining a uniform pressure field in the combustor, reducing turbulence and ensuring efficient cooling of turbine components.
Implementation Method 1
The air extraction ports are designed with a specific ratio of inlet to final area and passage length, incorporating bends with radii proportional to the inlet hydraulic diameter, to minimize pressure perturbations and ensure a smooth airflow contraction, maintaining a local Mach number range that prevents turbulence.
Data Source
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AI summary
An air extraction port (58) at a combustor (18) of a gas turbine engine (10) includes a port inlet (68) at a combustor case (28) of the combustor having an inlet area, a port outlet (70) having a final area, and a fluid passage (72) extending from the port inlet to the port outlet to convey an airflow (60), the port inlet sized and configured to extract the airflow from the combustor case at the same nominal upstream Mach number with a tolerance of +/-0.05.