Turbine Engine Heat Exchanger Bypass Valve for Leak Isolation
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Solution Overview
Problem
Existing turbomachine lubrication systems face challenges in efficiently controlling oil supply to air/oil heat exchangers, particularly in preventing oil leaks and ensuring adequate lubrication during varying flight conditions, which can lead to turbomachine shutdowns due to insufficient oil levels.
Innovation Solution
An assembly with a fluid distributor that includes a shutter, resilient biasing means, and electrical control to manage fluid flow between a main branch and a bypass branch, allowing for adaptive cooling and leak detection, automatically isolating the heat exchanger in case of leaks and adjusting fluid supply based on pressure and temperature thresholds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a thermostatic valve with solid wax is used to divert lubricant when temperature drops below a threshold, then the lubricant can be diverted during cold flight conditions, but the valve cannot completely shut off the oil supply to the heat exchanger and cannot withstand a high number of open/close cycles
Solution Approach 1:
The valve is divided into two independent control systems: a thermostatic valve for temperature-based diversion and a hydraulic valve for pressure-based complete shut-off. This segmentation allows each valve to specialize in its optimal function while working together to solve the reliability problem.
Solution Approach 2:
The hydraulic valve acts as an intermediary that can completely shut off oil supply to the heat exchanger when needed, complementing the thermostatic valve's temperature-based control. This intermediary mechanism provides the complete shut-off capability that the thermostatic valve alone cannot achieve.
2Adaptability or versatility
If a hydraulic valve is used to open when lubricant pressure differential exceeds a threshold and divert when temperature falls below a threshold, then the valve can respond to pressure and temperature changes, but the circulation of cold lubricant results in greater pressure losses and the valve operation is unstable
Solution Approach 1:
The system dynamically switches between different valve configurations based on operating conditions. The main valve remains in a stable closed position during normal operation, and only opens when specifically commanded by the control system, reducing unnecessary pressure losses from continuous operation.
Solution Approach 2:
The control system monitors operating conditions and provides feedback to the valve actuation system. This feedback mechanism ensures the valve opens only when truly necessary, preventing unnecessary pressure losses from continuous or unstable valve operation.
3Temperature
If the heat exchanger operates during certain turbomachine operating modes to cool the oil, then excessive oil cooling in cold flight conditions is prevented, but the system cannot completely shut off the oil supply and may experience leaks
Solution Approach 1:
The oil supply control is segmented into temperature-based diversion (thermostatic valve) and complete shut-off (hydraulic valve). This segmentation allows the system to prevent excessive cooling during cold flight while maintaining oil supply integrity through the additional shut-off mechanism.
Solution Approach 2:
The hydraulic valve provides a backup shut-off mechanism that can prevent oil leaks before they become problematic. By having this additional control mechanism in place beforehand, the system can respond to potential leak conditions and maintain reliability.
4Device complexity
If a simple valve mechanism is used for temperature-based lubricant diversion, then the device complexity is low, but the valve cannot withstand a high number of open/close cycles and cannot completely shut off oil supply
Solution Approach 1:
The simple thermostatic valve mechanism is segmented from the more complex hydraulic valve system. Each valve handles specific functions, allowing the simple valve to remain simple while the system as a whole achieves high reliability through the complementary hydraulic valve that handles complete shut-off and durability requirements.
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 controls fluid flow and cooling according to turbomachine speed, minimizes the impact of leaks, and facilitates leak detection, thereby preventing turbomachine shutdowns by ensuring reliable lubrication and efficient heat exchange.
Implementation Method 1
a valve movable between a main open position, in which it closes the bypass outlet and allows fluid to flow in the main branch, and a bypass position, in which it closes the main outlet and allows fluid to flow in the bypass branch
Implementation Method 2
The elastic means for actuation of the shutter is configured to move the shutter so that it closes the main outlet when a fluid pressure value is below a first threshold value
Data Source
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AI summary
The invention relates to an assembly (60) for a fluid circuit (40) of a turbine engine (1). The assembly (60) comprises a main branch (62), a fluid control valve (70), and a bypass branch (64) which is arranged parallel to the main branch (62). The fluid control valve (70) has a main outlet (73) which is fluidly connected to the main branch (62) and a bypass outlet (75) which is fluidly connected to the bypass branch (64). The fluid control valve (70) comprises a shutter (79), resilient biasing means (78) for biasing the shutter, and electrical actuation means (72, 74) for electrically actuating the shutter to a main open position or a bypass position. The resilient biasing means (78) for biasing the shutter is configured to bias the movement of the shutter (79) towards the bypass position when a fluid pressure value is lower than a first threshold value.