Inter-turbine Duct Guide Vanes for Gas Turbine Engines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional gas turbine engines face performance issues due to boundary layer separation in inter-turbine ducts, which are often elongated to compensate for radial size differences between high and low pressure turbines, leading to suboptimal efficiency and weight.
Innovation Solution
Incorporating guide vanes within the inter-turbine duct to prevent boundary layer separation, with a shroud and hub forming the flow path and guide vanes positioned to maintain smooth airflow, allowing for a shorter duct length and improved radial angle transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of stationary object
If the inter-turbine duct length is decreased to reduce weight and improve efficiency, then the radial angle increases, but boundary layer separation occurs which adversely affects low pressure turbine performance
Solution Approach 1:
Guide vanes are introduced as intermediary elements within the inter-turbine duct to control and direct the airflow. These vanes act as mediators between the high pressure turbine outlet and low pressure turbine inlet, preventing boundary layer separation by properly guiding the flow transition across the radial angle, thereby enabling shorter duct lengths without compromising turbine performance
Solution Approach 2:
The guide vanes modify the flow parameters (direction, velocity distribution) within the inter-turbine duct. By changing the angular distribution and radial velocity components of the airflow, the guide vanes prevent adverse pressure gradients that cause boundary layer separation, allowing the duct to achieve optimal size ratio between turbines while maintaining attached flow
2Reliability
If the inter-turbine duct is made elongated to reduce radial angle, then boundary layer separation is reduced, but the duct length and weight increase
Solution Approach 1:
The inter-turbine duct is segmented into functional zones by introducing guide vanes at strategic positions. The duct is divided into an upstream section, a guide vane region, and a downstream section, allowing each segment to perform specific flow control functions. This segmentation enables the duct to achieve effective flow control in a shorter overall length by concentrating flow management functions at specific locations rather than relying on extended duct length
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 guide vanes mitigate boundary layer separation, enabling a more compact and efficient turbine design with reduced pressure losses and weight, while maintaining optimal radial size ratios between turbines, and can be applied to both new and existing engine designs.
Implementation Method 1
Increasing the angle of the duct over a relatively short distance may result in boundary layer separation of the flow within the duct
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A turbine section (150) of a gas turbine engine is provided. The turbine section is annular about a longitudinal axis (102) and includes first turbine stage (160) with a first inlet and a first outlet (162); a second turbine stage (170) with a second inlet (172) and a second outlet; an inter-turbine duct (180) extending from the first outlet to the second inlet (172) and configured to direct an air flow from the first turbine stage to the second turbine stage; and a first guide vane (260) disposed within the inter-turbine duct (180), which size is radially less than 50% of the height of the duct (180).