Flow Rate Sensor Correction for Integration-Induced Measurement Error
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Solution Overview
Problem
Static flow meters, such as thermal or ultrasonic flow meters, become inaccurate when integrated into fluidic systems due to changes in flow conditions at the inlet and outlet, as they often interact with only a portion of the flow profile and are not affected by the entire flow channel, leading to inaccuracies in flow rate measurements.
Innovation Solution
A method and device for determining a flow rate that corrects the raw flow rate signal using a flow rate correction function based on a reference correction function, accounting for the integration error, and applying a flow rate rescaling factor that considers the kinematic viscosity difference between the fluid of interest and the reference fluid, allowing for accurate measurements across various fluids and conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a flow rate sensor is integrated into a fluidic system, then the flow rate can be measured in the system, but the measurement accuracy deteriorates due to changes in flow conditions at the inlet and outlet of the sensor
Solution Approach 1:
The patent applies parameter changes by determining a correction function that accounts for changes in flow conditions (such as flow profile distortions) when the sensor is integrated into the fluidic system. This correction function modifies the raw measurement signal to compensate for the altered flow parameters, thereby maintaining measurement accuracy despite the integration-induced changes in flow conditions.
2Device complexity
If a flow rate sensor interacts with only a portion of the flow profile, then the sensor structure can be simplified, but the measurement accuracy deteriorates when the flow profile changes due to system integration
Solution Approach 1:
The patent introduces a correction function as an intermediary element that mediates between the simplified sensor measurement and the actual flow rate. This correction function, determined through reference measurements with known flow rates, acts as a transfer function that translates the partial flow profile measurement into an accurate total flow rate measurement, compensating for the sensor's limited interaction with the full flow profile.
3Adaptability or versatility
If multiple reference correction functions are determined for different fluids, then the measurement accuracy for various fluids improves, but the device complexity and calibration resources increase
Solution Approach 1:
The patent achieves universality by determining a single correction function using a reference fluid that can then be applied to measure flow rates of different fluids in the same fluidic system. The correction function addresses the system integration effects that are common to all fluids, allowing the simplified sensor to provide accurate measurements across multiple fluid types without requiring separate correction functions for each fluid.
Data Source
AI summary
In a method of determining a flow rate of a flow of a fluid of interest in a fluidic system, a raw flow rate signal (Qsensor) is determined using a flow rate sensor. The raw flow rate signal is corrected using a flow rate correction function (Δ) to obtain a corrected flow rate signal (Qsensor,corr). The flow rate correction compensates for a flow rate signal error that is caused by integration of the flow rate sensor into the fluidic system. It is based on a reference correction function (δ) that is indicative of a flow rate signal error for a flow of a reference fluid due to the integration of the flow rate sensor into the fluidic system.