Propeller Blade Angle Control Circuit Oil Flow Management
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Solution Overview
Problem
Turboprop gas turbine engines face inefficiencies due to excess hydraulic fluid diversion, leading to increased oil temperature and potential component damage, as the pump supplies more fluid than needed during steady-state operations, causing unwanted heat buildup.
Innovation Solution
A propeller blade angle control circuit with a valve system that directs excess oil to an oil cooling line during steady-state operation, blocking access to this path during transient operations to maximize oil flow to the pitch change mechanism, thereby reducing overheating risks and optimizing hydraulic power usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is sized to meet the largest load requirements of the blade angle control system, then the system can handle peak hydraulic demands, but excess fluid is supplied during steady-state operation causing increased oil temperature
Solution Approach 1:
The invention extracts the excess hydraulic fluid from the main system by providing a dedicated bypass line that returns excess fluid directly to the pump inlet, separating the peak demand capability from the steady-state operation to prevent overheating
Solution Approach 2:
The invention uses a variable orifice valve that dynamically adjusts its opening based on system conditions, allowing excess fluid bypass during steady-state operation while maintaining full flow capability during peak demands, thus adapting the system behavior to match actual needs
2Productivity
If excess hydraulic fluid is diverted away from the blade angle control system toward the pump inlet, then the pump's largest load requirements are met, but this results in an undesirable increase in the temperature of the oil supplied to the pump
Solution Approach 1:
The invention introduces a bypass line as an intermediary pathway that allows excess fluid to circulate separately from the main blade angle control system, providing a dedicated route for heat management without interfering with the primary hydraulic function
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
This solution effectively manages oil flow to prevent overheating and ensure efficient hydraulic power distribution, enhancing the reliability and performance of the propeller blade angle control system by maintaining optimal oil temperatures and hydraulic power availability.
Implementation Method 1
The blade angle control system is actuated by hydraulic fluid which is supplied under pressure by a pump
Implementation Method 2
A propeller blade angle control circuit with a valve system that directs excess oil to an oil cooling line during steady-state operation, blocking access to this path during transient operations to maximize oil flow to the pitch change mechanism, thereby reducing overheating risks
Data Source
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AI summary
A control circuit (20) for changing the angle of propeller blades (17) includes a propeller pitch change mechanism (21), and a fixed-displacement pump (22) providing the supply of oil from an engine oil return system (13). A valve (30; 130) has an outlet port (33) to direct oil from a cavity (35) of the valve (30), and a pitch port (34) in fluid communication with the pitch change mechanism (21). A spool (36) of the valve (30) is operable between a first position and a second position to respectively open and close the outlet port (33), and direct oil flow away from or to the pitch change mechanism (21).