Aircraft Turbomachine Oil Tank Venting for Acceleration Stability
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Solution Overview
Problem
Existing turbomachine lubrication systems face challenges in maintaining oil supply and preventing oil loss during lateral and vertical accelerations, particularly due to insufficient oil sumps and the need for additional strainers and valves, which increase complexity and require power take-offs, while existing degassing systems are prone to submersion and inefficiency.
Innovation Solution
A lubrication reservoir design with a partitioned enclosure, including a suction strainer, static degassing device, and strategically positioned vents and pipes, which ensures continuous oil supply and prevents oil intrusion into vents and degassing devices during accelerations, using calibrated passages and elbow-shaped vent pipes to maintain oil levels and facilitate air evacuation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the oil sump is made deeper to ensure strainer immersion during lateral accelerations, then the ability to withstand lateral accelerations is improved, but the integration constraints of the reservoir are violated and the reservoir cannot be integrated in its environment
Solution Approach 1:
The reservoir is divided into two separate compartments: a first compartment containing the suction strainer and a second compartment containing the degassing device. These compartments are separated by a partition wall with controlled passages, allowing the system to maintain proper fluid levels in each compartment independently during accelerations without requiring excessive overall depth.
Solution Approach 2:
A valve system is introduced as an intermediary mechanism to control fluid flow between compartments. The valve opens or closes based on acceleration detection, regulating the passage of lubricant between compartments to ensure the suction strainer remains immersed while preventing oil loss from the degassing compartment.
2Reliability
If additional strainers and valves are added to maintain oil supply during accelerations, then the reliability of oil supply is improved, but the device complexity increases
Solution Approach 1:
The partition wall with controlled passages serves multiple functions: it separates the two compartments to maintain independent fluid levels, allows controlled fluid exchange between compartments during normal operation, and works with the valve system to prevent oil loss during accelerations. This multi-functional design reduces the need for additional separate components.
Solution Approach 2:
The valve system automatically responds to acceleration conditions and fluid level changes, opening or closing based on the operational state without requiring external control. The passages in the partition wall automatically regulate fluid flow between compartments based on pressure differential and acceleration, eliminating the need for complex external control systems.
3Productivity
If a rotating deaerator is used for degassing, then the degassing efficiency is improved, but the requirement for power take-off increases the device complexity and limits applicability
Solution Approach 1:
The static degassing device operates passively using the natural flow of lubricant returning from the turbomachine. The lubricant flows through the partition wall passages into the second compartment where air separation occurs naturally, with the separated air exiting through the vent outlet. This eliminates the need for rotating mechanisms or external power sources while maintaining effective degassing.
Solution Approach 2:
The rotating mechanical deaerator is replaced with a static degassing device that uses fluid dynamics and pressure differential to achieve air separation. The lubricant flow itself provides the driving force for air bubbles to rise and escape through the vent, replacing the need for mechanical rotation and power take-off.
4Productivity
If the vent is placed in the upper part of the tank to evacuate separated air, then the air evacuation function is improved, but the vent becomes prone to submersion during tank overturning causing oil loss
Solution Approach 1:
The reservoir is segmented into two compartments with the vent outlet positioned exclusively in the second compartment (deaerator compartment). The partition wall with controlled passages and valve system ensures that even if the tank overturns, the suction strainer compartment remains isolated, preventing oil from reaching and submerging the vent outlet.
Solution Approach 2:
The partition wall and valve system act as intermediaries that physically separate the vent outlet from the suction strainer compartment. During normal operation, controlled passages allow fluid exchange. During overturning, the valve closes to prevent oil flow toward the vent, protecting the vent outlet from submersion while maintaining air evacuation 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
The design ensures reliable oil supply and prevents oil loss during various accelerations, simplifies the system by eliminating the need for additional strainers and power take-offs, and maintains degassing efficiency by keeping vents and degassing devices above the oil level.
Implementation Method 1
a porous element (74) arranged between said inlet and outlet
Implementation Method 2
with reference to a direction and a sense of the gravitational force: in a lower part of said enclosure, a suction strainer (40) which is located in the vicinity of a bottom (41) of said enclosure
Implementation Method 3
two vent pipes (50), which have upper outlet ends (52) communicating with the vents (42) and which extend in the upper part (44) to lower inlet ends (54) opening into the tank below the degassing device (30), each pipe having an elbow (56)
Data Source
Figure 1~3
Figure 4
Figure 5~6
AI summary
The invention relates to a lubrication reservoir (14) for a turbine engine for an aircraft or self-propelled flying machine, comprising a suction strainer (40) in a lower part (38) of said chamber (26), and at least one degassing device (30) and at least one vent (42) in an upper part (44). The reservoir is characterised in that, in order to make it possible to supply the strainer (40) and prohibit lubricant (28) from intruding into said at least one vent (42), it comprises at least one first partition (46) that separates the lower part (38) from the upper part (44) and is pierced with calibrated holes (48), two vents arranged on either side of a vertical median plane (P) of the chamber (26) and two vent ducts (50) which extend into the upper part (44) below the degassing device (30), each duct (50) comprising a bend (56) and having said bend (56) located on the other side of said median plane (P) with respect to the inlet thereof.