Nested Duct Cooling Arrangement for Gas Turbine Casing
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Solution Overview
Problem
Existing cooling arrangements for gas turbine engine turbine casings are inefficient in directing cooling air effectively, leading to suboptimal engine performance due to the arrangement of circular ducts around the turbine case.
Innovation Solution
A 'duct-in-duct' cooling arrangement where a first cooling duct is located within a second cooling duct, allowing for separate fluid flows and improved distribution of cooling air to the turbine casing, with the second duct surrounding the first and featuring an annular flow passageway for unmodulated gas flow, and incorporating a butterfly valve for flow control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If circular ducts are arranged side-by-side around the turbine case, then cooling air can be supplied to the turbine casing, but the space utilization is inefficient and cooling distribution is suboptimal
Solution Approach 1:
The first cooling duct is nested within the second cooling duct, creating a duct-in-duct configuration. This allows both ducts to occupy the same spatial envelope, significantly improving space utilization while maintaining separate cooling fluid flows for optimized heat transfer to the turbine casing
2Reliability
If multiple separate ducts are provided for cooling air supply, then cooling coverage can be increased, but the device complexity increases
Solution Approach 1:
Multiple cooling duct functions are merged into a single integrated duct-in-duct assembly. The first and second cooling ducts are combined in a nested configuration, reducing the number of separate components while maintaining the capability to supply cooling air to multiple locations on the turbine casing through coordinated outlet holes
3Reliability
If cooling ducts are placed close to the turbine case to improve cooling efficiency, then heat transfer is enhanced, but electronic equipment mounting becomes difficult
Solution Approach 1:
The nested duct configuration creates additional spatial dimensions and surfaces for mounting electronic equipment. The outer surface of the second cooling duct and the outer surface of the first cooling duct provide multiple mounting locations, allowing electronic equipment to be positioned away from the turbine case while maintaining effective cooling through the duct outlets
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 configuration enhances cooling efficiency by minimizing space and allowing for controlled fluid flow, reducing the surface temperature of the inner duct and enabling the integration of electronic equipment, thus improving engine performance and reducing radiative heating effects.
Implementation Method 1
a first cooling duct (203) that is located within a second cooling duct (204)... wherein the first cooling duct is for a first cooling fluid flow and wherein the second cooling duct is for a second cooling fluid flow
Implementation Method 2
directing cooling fluid towards the turbine casing... reduce the clearance between the tips of the rotor blades of the turbine stage and the turbine case to improve engine performance
Data Source
AI summary
There is disclosed a cooling arrangement for a turbine casing (50) of a gas turbine engine (10). The cooling arrangement comprises a first cooling duct (203) that is at least partly within a second cooling duct (204). The first cooling duct is for a first cooling fluid flow and the second cooling duct is for a second cooling fluid flow which flows around the first cooling duct.