Mass Flow Meter Combining Volumetric and Density Sensors
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Solution Overview
Problem
Aircraft engine designers require highly accurate, wide-range, and fast-response flow meters for hydrocarbon fuel measurement, but existing volumetric flow meters lack the necessary accuracy and range to support modern engine control systems.
Innovation Solution
A combination of a volumetric flow meter with a densitometer, utilizing a variable area obstruction meter and differential pressure sensor, along with a fuel temperature sensor to calculate mass flow by correcting pressure and density signals, enabling precise mass flow computation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional volumetric flow meter is used, then the device complexity is low, but the measurement precision and flow range are insufficient for modern engine control requirements
Solution Approach 1:
The patent combines a volumetric flow meter and a densitometer into a single integrated mass flow measurement system. The volumetric flow meter measures volumetric flow rate while the densitometer measures fluid density, and these two measurements are combined to calculate mass flow rate, thereby achieving high-precision mass flow measurement without requiring a completely complex new device design
Solution Approach 2:
The integrated system performs multiple functions: it measures volumetric flow rate, measures fluid density, and calculates mass flow rate. This multi-functionality allows a single device to meet the high measurement precision requirements for mass flow while avoiding the complexity of multiple separate instruments
2Adaptability or versatility
If a volumetric flow meter with limited range is used, then the device is simple, but it cannot provide accurate measurements across the wide flow range required by aircraft engine control
Solution Approach 1:
By merging volumetric flow measurement with density measurement, the system achieves adaptability across wide flow ranges while maintaining precision. The densitometer component enables accurate density measurement that compensates for variations in fluid properties across different flow conditions, allowing the combined system to maintain measurement accuracy throughout the extended range
3Adaptability or versatility
If active controlling mechanisms are added to extend turn-down ratio, then the measurement range improves, but the device complexity increases
Solution Approach 1:
The system achieves extended turn-down ratio without active controlling mechanisms by using passive measurement principles. The volumetric flow meter and densitometer work together in a self-service manner, where the density measurement automatically compensates for flow rate variations, eliminating the need for complex active control systems to maintain measurement accuracy across the extended range
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 provides a highly accurate and reliable method for measuring mass flow over a wide range, enhancing the accuracy and service life of flow meters while accommodating varying fuel properties and flow rates.
Implementation Method 1
a differential pressure sensor to measure the pressure difference across the obstruction
Implementation Method 2
The densitometer relies on capacitance tubes to yield a density measurement of the fluid passing there through
Implementation Method 3
A fuel temperature sensor serves to correct both the pressure bridge signal as well as the density signal
Data Source
AI summary
A simple, passive and rugged device for measuring the flow rate of liquid. A variable area obstruction valve, a differential pressure sensor and a densitometer are combined in a single housing to provide for a highly accurate and precise measure of mass flow.