Aircraft Turbomachine Thrust Control via Variable-Pitch Rectifier Vanes
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for regulating the thrust of aircraft turbomachines at high dilution rates are inefficient due to large propeller inertia and imprecision in blade setting, leading to slow thrust variation and yield penalties.
Innovation Solution
A method involving open-loop regulation of thrust by varying the timing of the rectifier's blades and closed-loop calibration of propeller blades based on rotation speed, along with optional regulation of fuel flow to maintain a constant N2R/N1R ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the propeller size is increased to absorb and accelerate a large flow of air, then the bypass ratio is increased and fuel consumption is reduced, but the propeller inertia becomes large making speed variation slow
Solution Approach 1:
The invention divides the thrust regulation function into two independent parts: rectifier vanes that control thrust magnitude and propeller blades that maintain optimal rotational speed. This segmentation allows the large-inertia propeller to operate at constant speed while the rectifier vanes handle dynamic thrust adjustments, resolving the contradiction between large bypass ratio and slow speed variation.
Solution Approach 2:
The rectifier vanes act as an intermediary element between the power source and the large-inertia propeller. By adjusting the rectifier vane pitch, the system can rapidly modify thrust output without requiring the propeller itself to change speed, thus enabling fast thrust regulation despite the propeller's large mass.
2Ease of operation
If the propeller blade pitch is used to regulate thrust, then thrust control is achieved, but the inaccuracy in blade pitch leads to uncertainty in the operating point of the low-pressure compressor
Solution Approach 1:
Instead of using propeller blade pitch to control thrust (the conventional approach), the invention inverts the control logic by using rectifier vane pitch to regulate thrust. This inversion transfers the precision requirement from the propeller blades to the rectifier vanes, where more accurate pitch control can be achieved, thereby eliminating operating point uncertainty.
Solution Approach 2:
The invention extracts the thrust regulation function from the propeller blade pitch system and assigns it to the rectifier vane pitch system. This separation allows the propeller blades to focus solely on maintaining optimal operating conditions while the rectifier vanes handle thrust control with higher precision.
3Loss of energy
If the propeller size is increased to achieve high bypass ratio, then fuel consumption is reduced, but the device complexity increases
Solution Approach 1:
The rectifier vane system serves multiple functions: it regulates thrust magnitude, controls the operating point of the low-pressure compressor, and enables rapid response to pilot commands. By making the rectifier system multi-functional, the invention avoids adding separate systems for each function, thereby limiting the increase in device complexity while achieving high bypass ratio benefits.
Data Source
Figure 1
Figure 2
Figure 3~4
AI summary
Method and system for controlling the thrust of an aircraft turbomachine (100) having a high bypass ratio by direct action on a variable-pitch system (123) for varying the pitch of the vanes of a stator (121) of a low-pressure compressor (120) for the open-loop control of the thrust of the turbomachine and the closed-loop control of the pitch of the blades of a propeller (110) based on a rotational speed of the propeller (110).