Turbomachine Airfoil Clocking for Diffuser Pressure Uniformity
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Solution Overview
Problem
Existing turbomachines do not effectively address the circumferential variation of airflow pressure entering the diffuser, which reduces overall machine efficiency and aerodynamic robustness, as known clocking methods may even increase these variations to improve other aspects like energy efficiency or reduce vibration and stress.
Innovation Solution
The turbomachine airfoils are clocked relative to each other to reduce airflow pressure variations entering the diffuser by calculating and adjusting the relative positions of airfoil rows nearest the diffuser using computational fluid dynamics, specifically employing the Navier-Stokes solver equations to model airflow and pressure variations, and iteratively changing clocking positions to achieve targeted pressure uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If known clocking methods are used to improve energy efficiency or reduce vibration and stress in airfoils, then those specific performance aspects are improved, but circumferential variation in airflow pressure entering the diffuser increases
Solution Approach 1:
The invention changes the clocking position parameter of airfoil rows to optimize pressure distribution. By adjusting the relative angular positions of airfoil rows, the method transforms the flow field characteristics to reduce circumferential pressure variations at the diffuser while maintaining energy efficiency and reducing airfoil stress.
Solution Approach 2:
The invention introduces dynamic optimization of airfoil row positioning. The clocking positions are determined through computational fluid dynamics simulations that model the dynamic flow field, allowing for optimal positioning that balances multiple performance criteria including pressure uniformity, energy efficiency, and structural stress reduction.
2Loss of energy
If known clocking methods are used to improve energy efficiency or reduce vibration and stress in airfoils, then those specific performance aspects are improved, but aerodynamic robustness is reduced
Solution Approach 1:
The invention optimizes the clocking position parameter to achieve a balanced flow distribution. By carefully selecting the relative angular positions of airfoil rows, the method simultaneously improves energy efficiency, reduces airfoil stress, and enhances aerodynamic robustness through more uniform pressure distribution across the diffuser.
Solution Approach 2:
The invention employs computational fluid dynamics simulations that provide feedback on flow field characteristics. This feedback mechanism allows for iterative optimization of airfoil row positioning to achieve the desired balance between energy efficiency, structural performance, and aerodynamic stability.
3Productivity
If airfoil rows are clocked to reduce vane wake impact on rotating blades, then blade performance is improved, but circumferential variation in flow field entering the diffuser is not addressed
Solution Approach 1:
The invention extends the clocking optimization approach to serve multiple functions simultaneously. By optimizing the clocking positions of airfoil rows, the method addresses both the blade performance aspect (reducing vane wake impact) and the diffuser flow uniformity aspect (reducing circumferential pressure variation), making the system multi-functional in its optimization capability.
Solution Approach 2:
The invention adds another dimension to the optimization problem by considering both upstream blade performance and downstream diffuser flow characteristics. This multi-dimensional optimization approach allows for clocking positions that simultaneously improve blade efficiency and create uniform flow distribution at the diffuser, rather than optimizing for a single location.
Data Source
AI summary
Embodiments of the invention relate generally to turbomachines and, more particularly, to the positioning of airfoils to reduce pressure variations entering a diffuser. One embodiment includes a turbomachine comprising a diffuser, a plurality of airfoil rows, including a first airfoil row adjacent the diffuser, the first airfoil row being of a first type selected from a group consisting of stationary vanes and rotating blades, a second airfoil row adjacent the first airfoil row, the second airfoil row being of a second type different from the first type, and a third airfoil row of the first type adjacent the second airfoil row, wherein at least one of the plurality of airfoil rows is clocked, relative to another airfoil row of the turbomachine, reducing variations in airflow circumferential pressure at at least one spanwise location in the diffuser adjacent the first airfoil row in an operative state of the turbomachine.