Bi-directional Oscillating Jet Flowmeter Series Design
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Solution Overview
Problem
Fluidic oscillator flowmeters currently only measure flow accurately in one direction, failing to accurately measure reverse flows, which is a limitation in applications where bidirectional flow measurement is necessary, such as domestic water metering, and typically require a non-return valve to prevent reverse flow.
Innovation Solution
A bi-directional flowmeter design comprising two fluidic oscillator devices connected in series, each with distinct oscillation characteristics for forward and reverse flow directions, allowing for accurate measurement of flow rates in both directions without the need for a non-return valve, using symmetric or asymmetric geometries and sensing techniques to differentiate between forward and reverse flow signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single fluidic oscillator device is used, then the device complexity is low, but the flow measurement capability is limited to one direction only
Solution Approach 1:
The flowmeter is divided into two separate fluidic oscillator devices: a first fluidic oscillator for measuring forward flow and a second fluidic oscillator for measuring reverse flow. Each oscillator is optimized for its specific flow direction, enabling bidirectional measurement capability while maintaining relatively simple individual device structures.
Solution Approach 2:
The flowmeter system achieves multi-functionality by combining two fluidic oscillators that can each measure flow in their respective directions. The system can now perform both forward flow measurement and reverse flow measurement, making it universally applicable to bidirectional flow scenarios without requiring separate meters.
2Measurement precision
If two fluidic oscillator devices are connected in series, then bidirectional flow measurement accuracy is improved, but the pressure drop increases
Solution Approach 1:
Each fluidic oscillator is designed with specific geometric characteristics optimized for its measurement direction. The first oscillator has geometry optimized for forward flow measurement while the second oscillator has geometry optimized for reverse flow measurement. This local optimization ensures high measurement accuracy in each direction while minimizing unnecessary pressure losses.
3Reliability
If a non-return valve is installed downstream, then reverse flow prevention is achieved, but the device complexity and flow restriction increase
Solution Approach 1:
The flowmeter system performs its own reverse flow measurement function through the second fluidic oscillator, eliminating the need for external non-return valves. The system serves its own need for bidirectional flow control and measurement, reducing overall system complexity while maintaining reliability.
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
Enables accurate measurement of both forward and reverse flows with identical performance characteristics, improving linearity and low flow rate measurement capabilities, and eliminating the need for a separate flow conditioner or non-return valve, while maintaining a comparable pressure drop to a single fluidic oscillator.
Implementation Method 1
By means of the Coanda effect the jet naturally attaches to one wall or the other
Implementation Method 2
the feedback flow feeds a separation bubble between the jet and the diffuser wall and forces the jet away from the wall
Data Source
AI summary
A bi-directional flowmeter comprises a first fluidic oscillator device arranged to measure the flow of fluid in a first direction and a second fluidic oscillator device arranged to measure the flow of fluid in a second direction opposite to the first direction and in which the two oscillators devices are connected together in series between an inlet port and an outlet port of the flowmeter between which the fluid to be measured can flow.