Forced Air Supply System for Engine Cavity Under Negative-G
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Solution Overview
Problem
Turbine engines face difficulties in removing lubricant under negative-g forces, leading to accumulation and potential flooding of the oil sump, which can cause heat generation and other undesirable conditions due to conventional scavenging methods being ineffective.
Innovation Solution
A forced air supply system is implemented, featuring a vent line and inlet connected to a forced air supply line with a valve and negative-g sensor, which delivers forced air to the oil sump to drive out lubricant and air during negative-g events, preventing flooding and ensuring efficient lubricant removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional scavenging methods are used under negative-g forces, then the system structure remains simple, but lubricant removal becomes ineffective leading to accumulation and flooding
Solution Approach 1:
The system introduces a forced air supply that activates before or during negative-g events to preemptively push lubricant toward the scavenge pickup, preventing accumulation before it occurs. This preliminary action ensures lubricant removal effectiveness without requiring complex active scavenging mechanisms during the critical negative-g period.
Solution Approach 2:
The invention uses pneumatic pressure from the forced air supply system to move lubricant against the effects of negative-g forces. By introducing pressurized air into the sump, the system creates a pneumatic driving force that overcomes the gravitational anomaly, maintaining effective lubricant removal without complex mechanical scavenging components.
2Object-affected harmful factors
If forced air supply is implemented to remove lubricant during negative-g events, then lubricant accumulation is prevented, but system complexity increases
Solution Approach 1:
The system uses forced air as an intermediary substance to transfer momentum and push lubricant toward the scavenge pickup. Rather than directly mechanically moving lubricant during negative-g events, the intermediary air stream facilitates lubricant removal, reducing the need for complex direct-acting mechanical components while effectively preventing flooding and heat generation.
3Reliability
If scavenge pickup is positioned for conventional operation, then the structure remains simple, but lubricant cannot be removed under negative-g forces as it pools on the top surface
Solution Approach 1:
The forced air supply creates an upward pneumatic force that counteracts the downward pooling effect of negative-g forces on lubricant. This anti-weight approach using pressurized air prevents lubricant from accumulating on the top surface of the sump, maintaining scavenge pickup effectiveness without requiring repositioning or complex adaptive mechanisms.
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 system effectively reduces the risk of lubricant accumulation and flooding by using forced air to push lubricant out of the sump through a vent line, maintaining engine performance and preventing heat-related issues during sustained negative-g conditions.
Implementation Method 1
an inlet in a second surface of the enclosure, the inlet in fluid communication with a forced air supply line to deliver forced air to the oil sump
Implementation Method 2
a valve and negative-g sensor, which delivers forced air to the oil sump
Data Source
AI summary
A forced air supply system is provided to deliver forced air to fluid or a mixture of fluid and air in an enclosure of a cavity of a gas turbine engine when the gas turbine engine experiences a negative-gravity force event. Methods are also provided for removing fluid and/or air from the enclosure when the gas turbine engine experiences the negative-gravity force.