Fuel Feed Circuit Flow Control for Two-Phase Pump Cavitation
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Solution Overview
Problem
The operation of low-pressure pumps in fuel feed circuits of turbine engines is compromised by unpredictable two-phase flow conditions at the interface between the airplane and the engine, leading to cavitation and potential damage, due to unknown flight conditions and incompatible designs between aircraft and engine manufacturers.
Innovation Solution
A method to regulate the flow rate in the feed circuit by determining the gas content in the upstream duct and adjusting it when exceeding a threshold, transitioning from turbulent cavitation to supercavitation mode to stabilize the flow and prevent pump damage, using a phase measurement tool and control unit to modify the flow rate without overdimensioning the pump.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the pump is overdimensioned to avoid cavitation, then pump reliability is improved, but device weight and size increase
Solution Approach 1:
The patent changes the operating parameters of the pump by actively adjusting the flow rate based on real-time cavitation detection. Instead of overdimensioning the pump for worst-case scenarios, the system dynamically adapts the flow rate to maintain reliable operation at the optimal design point, thereby avoiding the need for a heavier, oversized pump.
Solution Approach 2:
The patent implements a feedback control system using a phase measurement tool to detect cavitation in real-time. The detection unit monitors the flow phase, and the control unit adjusts the flow rate accordingly to prevent cavitation. This closed-loop feedback mechanism ensures pump reliability without requiring an oversized pump design.
2Reliability
If the flight envelope is limited to avoid low pressure conditions, then pump reliability is improved, but operational versatility deteriorates
Solution Approach 1:
The patent transforms the static approach of limiting the flight envelope into a dynamic solution. The system actively monitors flow phase in real-time and dynamically adjusts the flow rate to prevent cavitation. This allows the aircraft to operate across the full flight envelope without permanent restrictions, as the system adapts to changing conditions to maintain pump reliability.
Solution Approach 2:
The real-time feedback from the phase measurement tool enables the system to respond to actual flow conditions rather than relying on conservative pre-defined limits. The control unit receives continuous feedback about cavitation risk and adjusts operating parameters accordingly, allowing full utilization of the aircraft's performance capabilities while maintaining pump protection.
3Reliability
If the flow rate is increased to prevent cavitation, then pump reliability is improved, but energy consumption increases
Solution Approach 1:
The patent optimizes the flow rate parameter dynamically rather than maintaining a constantly high flow rate. The control unit adjusts the flow rate to the minimum necessary level to prevent cavitation based on real-time detection, avoiding unnecessary energy consumption while maintaining pump reliability.
Solution Approach 2:
The feedback control system ensures that flow rate increases occur only when cavitation is detected or anticipated. The phase measurement tool provides continuous feedback, allowing the system to maintain energy-efficient operation during normal conditions and only increase flow rate when necessary to prevent cavitation, thereby minimizing overall energy consumption.
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 method effectively prevents turbulent cavitation, reduces the risk of pump malfunction, and avoids the need for limiting flight envelopes or overdimensioning the pump, thereby maintaining engine performance while minimizing weight and size.
Implementation Method 1
a phase measurement tool (30) arranged in the upstream duct (10a), downstream from the interface (I)
Implementation Method 2
transitioning from turbulent cavitation to supercavitation mode to stabilize the flow
Implementation Method 3
transitioning from turbulent cavitation to supercavitation mode
Data Source
AI summary
A method of regulating a feed circuit including at least a first pump and an upstream duct leading to the first pump, the method including the steps of: determining the gas content of a flow in the upstream duct feeding the first pump; and, when the value of the gas content in the upstream duct, as determined in the determining step, is greater than or equal to a predetermined threshold value, modifying the flow rate of the flow feeding the first pump.