Turbomachine Guide Vane Ring Radial Offset Leakage Control
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Solution Overview
Problem
Turbomachines experience efficiency impairment due to turbulence caused by leakage between the inner ring and guide blades, which affects the main airflow.
Innovation Solution
The guide vane ring design features blade plates with front and rear surface areas that have a radial offset relative to the inner ring surface, reducing leakage by delaying air flow and minimizing suction effects in the gap between the blade plate and the inner ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the guide vanes are mounted radially externally with adjustable pins interacting with the outer housing, then the guide vanes can be actuated to assume different pivoting positions for optimal operating conditions, but leakage occurs between the inner ring and the blade plate of the guide blade
Solution Approach 1:
The blade plate is segmented into a front surface area and a rear surface area that are radially offset relative to the inner ring surface. This segmentation allows the leakage flow path to be divided and controlled, with the front surface area preventing air from entering the gap between the rear surface area and the inner ring, thus reducing overall leakage while maintaining adjustability.
Solution Approach 2:
The solution introduces a radial dimension offset between the front and rear surface areas of the blade plate and the inner ring surface. By creating this radial offset, the patent adds a dimensional control mechanism that prevents leakage without restricting the pivoting adjustability of the guide vanes in their operational positions.
2Ease of operation
If air enters the gap between the walls of the recesses in the inner ring and the blade plate, then the guide vanes can be actuated, but turbulence is caused that has a detrimental effect on the main air flow and impairs the efficiency of the turbomachine
Solution Approach 1:
The blade plate is divided into front and rear surface areas with radial offset, creating separate flow control zones. The front surface area acts as a barrier that prevents air from entering the gap, eliminating turbulence while preserving the actuation mechanism's functionality.
Solution Approach 2:
The front surface area of the blade plate serves as an intermediary element between the actuation mechanism and the main airflow path. It mediates by blocking the gap that would otherwise allow leakage and turbulence, thus protecting the main flow while permitting guide vane actuation.
3Loss of energy
If the blade plates have front and rear surface areas with radial offset to the inner ring surface, then leakage flow is reduced and efficiency is enhanced, but the structural complexity of the guide vane ring increases
Solution Approach 1:
The radial offset is applied locally only to specific surface areas of the blade plate (front and rear surfaces) rather than to the entire structure. This localized application achieves leakage reduction while minimizing the increase in overall structural complexity, as only specific regions of the blade plate are modified.
Solution Approach 2:
The patent changes the radial position parameter of specific surface areas of the blade plate relative to the inner ring surface. By adjusting this radial offset parameter locally, the leakage flow is controlled without requiring complex structural modifications to the entire guide vane ring assembly.
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 reduces leakage flow, enhancing the turbomachine's efficiency and pumping limit by guiding the main flow effectively and minimizing mixing with the leakage air.
Implementation Method 1
air enters the gap between the walls of the recesses in the inner ring and the blade plate used on the pressure side of the airfoil on the rear side of the inner ring
Implementation Method 2
The turbulence caused by this leakage has a detrimental effect on the main air flow and thus impairs the efficiency of the turbomachine
Data Source
Figure 1~2
Figure 3
AI summary
A guide vane ring according to the invention for a turbomachine minimizes leakage flow passing through a recess (11) into which the blade plate of a guide vane is inserted. It comprises a guide vane array with a plurality of guide vanes (20), each with a blade (24) and a blade plate (21), and an inner ring (10) with an inner ring surface (12) facing the plurality of guide vanes. The blade plates (21) have—viewed in the direction (R) of a intended main flow through the turbomachine—a front and a rear surface region (22a, 22b). The front and/or the rear surface region (22a, 22b) of at least one of the blade plates exhibits a radial offset (31a, 31b) to the inner ring surface (12) (relative to a central axis (X) of the inner ring (10)) in a nominal and/or maximum opening position of the guide vane.