Turbine Blade Pitch Hydraulics With Backup Feathering Supply
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing blade pitch control systems for aircraft turbine engines are inefficient due to the mass and bulk of counterweights used for feathering, and they fail to reliably feather blades in case of a fault in the rotating oil transfer bearing, leading to potential catastrophic consequences.
Innovation Solution
A pitch setting device with an auxiliary pressurized fluid supply circuit in the rotating reference frame that stores hydraulic energy close to the actuator, allowing for reliable feathering of blades even if the main hydraulic actuation fails, using a sliding valve to switch between main and auxiliary fluid sources.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If counterweights are used for feathering blades, then the feathering function is achieved, but the device mass and bulk increase significantly
Solution Approach 1:
The patent replaces the mechanical counterweight system with a hydraulic actuation system. The feathering function is achieved through a hydraulic actuator that uses pressurized fluid to rotate the blades to the feathered position, eliminating the need for heavy counterweights and their associated gear mechanisms.
Solution Approach 2:
The patent employs a hydraulic system with a pump, fluid distribution lines, and hydraulic actuators to achieve blade feathering. The hydraulic actuator converts fluid pressure into mechanical motion to rotate the blades, providing a lightweight alternative to mechanical counterweights while maintaining reliable feathering capability.
2Ease of operation
If a rotating oil transfer bearing is used to supply hydraulic fluid, then the hydraulic actuator can be mounted on the rotor, but the system fails to feather blades if the bearing fails
Solution Approach 1:
The patent incorporates a reservoir mounted on the rotor that is pre-filled with hydraulic fluid. This preliminary action ensures that even if the rotating oil transfer bearing fails, the hydraulic actuator has sufficient fluid on hand to complete the feathering operation, thereby maintaining feathering reliability independent of the bearing's operational status.
Solution Approach 2:
The system includes a backup supply of hydraulic fluid stored in the rotor-mounted reservoir, which acts as a cushion against the potential failure of the rotating oil transfer bearing. This beforehand cushioning ensures that the feathering function remains reliable even when the main fluid supply path is compromised.
3Reliability
If an electrically controlled pump is added to the stationary frame for feathering, then feathering is possible, but it is incompatible with the rotating oil transfer bearing architecture
Solution Approach 1:
The patent merges the hydraulic fluid storage function with the rotor structure by mounting the reservoir directly on the rotor. This integration eliminates the need for a separate electrically controlled pump in the stationary frame, as the rotor-mounted reservoir works in conjunction with the existing rotating oil transfer bearing architecture, thereby maintaining system compatibility while enabling feathering capability.
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
Enables rapid and reliable feathering of blades without the need for heavy counterweights, ensuring safety even if the rotating oil transfer bearing fails, by utilizing stored hydraulic energy near the actuator to maintain blade control.
Implementation Method 1
a fluid transfer bearing (40) configured to transfer pressurised fluid from the main supply source (32) towards each of the chambers (24a, 24b) of the control system (14) arranged in a rotating reference frame of the turbine engine via the supply means (30)
Implementation Method 2
a movable body in translation along the longitudinal axis X relative to said stationary body and separating the stationary body into two chambers of variable volume (24a, 24b), the movable body being connected to the connection mechanism
Data Source
AI summary
A device for setting the pitch of blades for a turbine engine, including a control system acting on a linkage mechanism and including an actuator having two chambers; —a supply member coupled to a fluid transfer bearing for transferring a pressurised fluid from a main supply source in a fixed frame of reference to the chambers; —an auxiliary supply circuit which is arranged in a rotating frame of reference and is connected to the supply member and to the main supply source, the supply member being configured to: —in normal operation, allow fluid to pass from the main supply source to the chambers and to the auxiliary supply circuit, and—in the event of a break in the supply to the chambers from the main supply source, allow pressurised fluid to pass from the auxiliary supply circuit to the chambers.