Flow Metering Pressure Taps in Recirculation Zones
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Solution Overview
Problem
Current fuel metering systems in gas turbine engines face challenges in accurately sensing fuel metering parameters across varying pressure ranges, leading to inefficiencies and increased emissions.
Innovation Solution
A flow metering device with a flow tube, motor, inlet nozzle, and outlet nozzle that create recirculation zones for pressure taps, minimizing dynamic pressure effects and allowing for more accurate static pressure measurements, combined with a method to calculate a correction factor for enhanced outlet pressure sensing accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If pressure taps are positioned in high-velocity flow regions to capture dynamic pressure effects, then the responsiveness to flow changes improves, but measurement accuracy deteriorates due to turbulence and dynamic pressure interference
Solution Approach 1:
The patent extracts the pressure measurement function from the high-velocity flow region by positioning pressure taps in recirculation zones where flow velocity is reduced and turbulence is minimized. This separation allows the pressure measurement system to operate independently from the dynamic flow effects, achieving accurate static pressure measurements while maintaining flow responsiveness through the recirculation zone's inherent flow characteristics
Solution Approach 2:
The recirculation zone acts as an intermediary region between the high-velocity inlet flow and the pressure measurement points. This intermediate zone reduces flow velocity and dissipates turbulence before the fluid reaches the pressure taps, thereby mediating the conflict between flow responsiveness and measurement accuracy by providing a transition region that preserves flow information while eliminating measurement interference
2Device complexity
If conventional pressure measurement methods are used without recirculation zones, then the device structure remains simple, but measurement accuracy deteriorates across varying pressure ranges
Solution Approach 1:
The patent introduces dynamic flow recirculation zones that adapt to varying pressure ranges and flow conditions. The recirculation zones are created by the interaction between the inlet nozzle, flow tube, and outlet nozzle, which naturally adjust the recirculation pattern based on operating conditions. This dynamic approach maintains measurement accuracy across varying pressure ranges without requiring complex adjustable mechanisms or multiple measurement systems
3Measurement precision
If multiple separate pressure measurement devices are used to achieve high accuracy across all parameters, then measurement precision improves, but device complexity and cost increase
Solution Approach 1:
The recirculation zone structure serves multiple functions simultaneously: it conditions the flow for accurate pressure measurement, reduces turbulence, and provides a stable measurement environment across varying operating conditions. By integrating these functions into a single structural feature rather than requiring separate devices for each function, the patent achieves high measurement precision while maintaining relative system simplicity
Solution Approach 2:
The patent combines flow conditioning and pressure measurement functions into a unified structure where the recirculation zones are formed by the integration of the inlet nozzle, flow tube, and outlet nozzle. This merging eliminates the need for separate external flow conditioning devices and multiple independent pressure measurement systems, achieving both high accuracy and simplified device complexity
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 solution significantly improves the accuracy of fuel flow regulation, reducing measurement errors and eliminating the need for external pressure measurement devices, achieving precision in fuel delivery and emissions reduction.
Implementation Method 1
The inlet nozzle, the flow tube, and the outlet nozzle define a flow path that has a plurality of recirculation zones. At least one of the inlet pressure tap and the outlet pressure tap opens within one of the recirculation zones.
Data Source
AI summary
A flow metering device includes a flow tube, a motor for positioning the flow tube, an outlet nozzle in fluid communication with the flow tube, and an inlet nozzle in fluid communication with the flow tube. The outlet nozzle has an outlet pressure tap and the inlet nozzle has an inlet pressure tap. The inlet nozzle, the flow tube, and the outlet nozzle define a flow path that has a plurality of recirculation zones. At least one of the inlet pressure tap and the outlet pressure tap opens within one of the recirculation zones.