Adaptive Pre-swirler for Gas Turbine Cooling
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Solution Overview
Problem
Existing gas turbine systems face inefficiencies in cooling due to variations in operating conditions, leading to suboptimal swirl ratios between cooling airflow and rotor speed, which can result in increased temperatures and reduced machine efficiency, potentially causing premature component deterioration or damage.
Innovation Solution
A gas turbine unit with an adaptive pre-swirler that utilizes Coanda effect-based flow channels with variable outlet angles and curvature ratios to maintain a constant tangential speed component of the cooling airflow, regardless of operating conditions, by imparting rotation through a combination of first and second curves that adjust airflow deflection based on speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a pre-swirler is designed to achieve an optimum swirl ratio in certain working conditions, then the cooling efficiency is improved in those conditions, but the cooling efficiency deteriorates when operating conditions change
Solution Approach 1:
The pre-swirler incorporates a variable geometry mechanism that allows the swirl angle to be dynamically adjusted based on operating conditions. The swirler blades can change their orientation to modify the tangential component of the cooling airflow, enabling the system to maintain optimal swirl ratio across different power outputs and rotor speeds, thereby resolving the contradiction between optimized performance at specific conditions and adaptability to varying conditions
Solution Approach 2:
The invention changes the geometric parameters of the pre-swirler, specifically the swirl angle and blade orientation, to adapt to different operating conditions. By varying these parameters in response to changes in airflow speed and rotor speed, the system maintains the optimal relationship between the tangential speed component of cooling airflow and rotor speed, ensuring consistent cooling efficiency across the full range of operating conditions
2Productivity
If the power supplied changes, then the output capability is improved to meet user demand, but the swirl ratio deviates from the optimum value
Solution Approach 1:
The system incorporates feedback mechanisms that monitor operating conditions such as airflow speed and rotor speed, and automatically adjust the pre-swirler geometry to maintain the optimal swirl ratio. This feedback control ensures that regardless of power output changes, the tangential speed component of the cooling airflow remains proportionate to the rotor speed, preventing deviation from the optimum swirl ratio and maintaining reliable cooling performance
Solution Approach 2:
The pre-swirler design allows dynamic adjustment of the swirl angle in response to power output changes. As the power supplied varies to meet user demand, the swirler blades dynamically reposition themselves to maintain the correct relationship between tangential airflow speed and rotor speed, ensuring that productivity changes do not compromise the optimization of the swirl ratio
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 adaptive pre-swirler ensures optimal cooling efficiency across various operating conditions, maintaining a consistent tangential speed component and preventing pressure reductions and temperature increases, thus enhancing the overall efficiency and longevity of the turbine components without requiring adjustments or moving parts.
Implementation Method 1
the joining section forms a first curve and is configured to deviate the cooling airflow by Coanda effect by a variable angle according to the absolute value of the inlet speed
Data Source
Figure 1~9
Figure 2
Figure 3~4
AI summary
A gas turbine unit includes: a compressor (4) and a turbine (5) along an axis (A); a cooling air circuit (12) to convey cooling air towards the turbine (5); and a pre-swirler (15) that imparts a rotation about the axis (A) to the cooling airflow. The pre-swirler (15) is equipped with flow channels (17) each having an inlet portion (17a), an outlet portion (17b) and a joining section (17c). The joining section (17c) forms a curve shaped so that a wall (17d) of the joining section (17c) on the inside of the curve deviates the cooling airflow about the axis (A), by Coanda effect at an angle correlated to an absolute value of an inlet speed (VI) of the cooling airflow. A passage section (S2) of the outlet portion (17b) allows a plurality of outlet angles of the cooling airflow, in accordance with the rotation caused by the joining section (17c).