Generalized Propeller Model for Real-Time Turbomachine Performance
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Solution Overview
Problem
Current methods are unable to quickly and precisely model the performance of a pair of counter-rotating propellers under various operating conditions, particularly for incident air flows with tangential components, leading to lengthy calculation times and inability for real-time determination of performance.
Innovation Solution
A generalized theoretical model is introduced, defining dimensionless coefficients for a downstream propeller experiencing a gyrating incident air flow, allowing for real-time performance determination by parameterizing the model with axial and tangential components of the air flow, pitch angles, and drive speeds, and regulating propeller pitch based on calculated traction and power performances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex aerodynamic methods are used to model the pair of propellers for specific operating conditions, then measurement precision is improved, but loss of time increases significantly (several hours of calculation)
Solution Approach 1:
The patent segments the complex aerodynamic modeling problem into two parts: (1) a simplified theoretical model that provides quick estimates, and (2) complex aerodynamic methods that are applied only to specific critical operating conditions. This segmentation allows most calculations to be performed rapidly while maintaining precision where needed.
Solution Approach 2:
The patent changes the parameters of the theoretical model by introducing correction factors that account for the gyration of airflow. By modifying the standard theoretical model parameters rather than using full complex aerodynamic methods, the patent achieves acceptable precision with much reduced calculation time.
2Ease of operation
If a conventional theoretical model is used for the downstream propeller, then ease of operation is improved, but measurement precision deteriorates because the model cannot account for tangential components of incident airflow
Solution Approach 1:
The patent introduces an intermediary correction factor that bridges the simple theoretical model and the complex reality of gyrating airflow. This correction factor acts as a mediator that allows the simple model to account for tangential components without requiring complex aerodynamic calculations.
Solution Approach 2:
The patent modifies the conventional theoretical model by changing its parameters to include the effects of tangential airflow components. This allows the model to remain simple in structure while accurately representing the complex physical conditions through adjusted parameters.
3Manufacturing precision
If complex aerodynamic methods are used for all operating conditions, then manufacturing precision is improved, but productivity decreases due to lengthy calculation times preventing real-time determination
Solution Approach 1:
The patent segments the operating conditions into different categories and applies different modeling approaches: a simplified model with correction factors for most conditions, and full complex aerodynamic methods only for specific critical conditions. This segmentation maintains precision while enabling real-time determination for the majority of operating scenarios.
Solution Approach 2:
The patent changes the modeling approach by introducing correction factors that allow the simplified model to achieve acceptable precision across a wide range of operating conditions, eliminating the need for computationally intensive complex aerodynamic methods in most cases and thereby enabling real-time performance determination.
Data Source
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AI summary
A method of determining the performance of at least one propeller of a turbomachine in an incident air stream (V) comprising an axial component (Vz) and a tangential component (V), said propeller being modelled by a generalized theoretical model (Mg) defined, for a plurality of angles of pitch (ß) of the propeller, by a set of nondimensional coefficients including at least one generalized progress coefficient (Jg), a generalized power coefficient (CPg) and a generalized traction coefficient (CTg) which are defined by the following formulae: Formula (I) method in which: the generalized theoretical model (Mg) of the propeller is parameterized with inlet conditions for the turbo machine including at least the axial component (Vz), the tangential component of the incident air stream (V), the angle of pitch (ß) and the speed of entrainment (u) of the propeller; and at least the performance in traction (T) and in power (P) of said propeller is deduced from the parameterized generalized theoretical model (Mg).