Flow Sensing Module Orifice Restrictor Noise Reduction
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Solution Overview
Problem
Flow sensing modules in low flow applications face challenges in reducing noise associated with detecting fluid flow, particularly due to turbulence and non-uniform pressure and velocity profiles, which affect the accuracy of flow rate and pressure measurements.
Innovation Solution
The implementation of a flow sensing module with a flow restrictor that includes a series of orifices and support rods to create a pressure drop and straighten fluid flow, reducing turbulence and noise, while maintaining a steady differential pressure across sensing ports for improved measurement accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If flow rate control mechanisms detect fluid flow in low flow applications, then flow rate measurement capability is achieved, but noise and measurement accuracy deteriorate due to turbulence and non-uniform pressure and velocity profiles
Solution Approach 1:
The flow channel is segmented into distinct zones: an upstream section, a flow restrictor section with multiple orifices, and a downstream section. This segmentation allows the flow to be divided into multiple smaller streams that can be laminarized individually, reducing overall turbulence and improving measurement accuracy in low flow applications.
Solution Approach 2:
A flow restrictor with multiple orifices is introduced as an intermediary element between the upstream and downstream flow channels. This intermediary device creates a controlled pressure drop and forces the fluid to pass through defined orifices, which laminarizes the flow and reduces turbulence before it reaches the sensing ports, thereby reducing noise and improving measurement accuracy.
2Object-affected harmful factors
If a flow restrictor with multiple orifices is introduced to laminarize flow, then turbulence and noise are reduced, but device complexity increases
Solution Approach 1:
The flow restrictor is designed to perform multiple functions simultaneously: it creates a controlled pressure drop across the flow channel, laminarizes the fluid flow through its orifice structure, and provides a reference flow path for differential pressure sensing. This multi-functionality reduces the need for additional separate components, thereby limiting the increase in device complexity while achieving flow laminarization and noise reduction.
Solution Approach 2:
The flow restrictor utilizes a porous or multi-orifice structure that allows fluid to pass through multiple small openings. This porous configuration naturally laminarizes the flow by breaking up large turbulent eddies into smaller, more controlled streams, reducing noise without requiring complex active flow control mechanisms.
3Measurement precision
If sensing ports are positioned close to the flow restrictor to capture pressure differential, then sensitivity to flow changes increases, but measurement accuracy deteriorates due to turbulent flow conditions
Solution Approach 1:
The flow restrictor is positioned upstream of the sensing ports, performing the action of laminarizing the flow before the fluid reaches the measurement zone. By preliminary straightening the flow and establishing a more uniform velocity profile before the sensing ports, the system can accurately detect pressure differentials without the interference of turbulence, thereby maintaining both sensitivity and measurement accuracy.
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 enhances the accuracy of flow rate and pressure measurements by laminarizing fluid flow and reducing noise, particularly in low flow rate and pressure applications, allowing for higher sensitivity and reliable data capture.
Implementation Method 1
The flow restrictor may have an inlet edge and an outlet edge, with a plurality of orifices extending between the inlet edge and the outlet edge
Implementation Method 2
The implementation of a flow sensing module with a flow restrictor that includes a series of orifices and support rods to create a pressure drop and straighten fluid flow, reducing turbulence and noise
Data Source
AI summary
A flow sensing module is provided for determining a flow rate of a fluid flowing through a flow channel. The flow sensing module may include an integrated flow restrictor, sometimes including a plurality of concentric ribs defining a plurality of orifices shaped to match the curvature of the wall of the flow channel. A first sensing port may open into the flow channel upstream of the flow restrictor, and a second sensing port may open into the flow channel downstream of the flow restrictor. A flow rate of a fluid flowing through the flow channel may be determining using a differential pressure between the first and second ports created by the flow restrictor, either using a flow sensor or a pressure sensor. The particular arrangement and relative dimensions of the orifices of the flow restrictor and the pressure ports can result in substantially reduced noise.