Micro Viscometer Using Parallel Helmholtz Resonators for Gas Viscosity
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Solution Overview
Problem
Existing viscometers face limitations in measuring viscosity accurately with small fluid volumes, particularly for gases, due to large size requirements and high error margins, and are restricted to low frequency measurements, making them unsuitable for liquids and gases with limited frequency range.
Innovation Solution
A micro viscometer design featuring two Helmholtz resonators in parallel, with thin films and piezoelectric layers, allows for vibration-induced fluid measurement across a broader frequency range, enabling precise viscosity determination with minimal fluid volume, including gases, by using MEMS technology to expand the frequency domain and reduce size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a traditional Helmholtz resonator viscometer is used, then gas viscosity can be measured, but the device occupies large space and has high error margin (38%)
Solution Approach 1:
The patent divides the traditional single large Helmholtz resonator into multiple smaller resonators arranged in parallel. This segmentation reduces the overall device footprint while maintaining the ability to measure gas viscosity through the combined acoustic response of the multiple resonators, directly addressing the contradiction between measurement accuracy and device size.
Solution Approach 2:
The patent replaces the traditional mechanical Helmholtz resonator structure with a micro-electromechanical system (MEMS)-based acoustic resonator. This substitution uses piezoelectric materials and micro-fabricated structures to achieve the same viscosity measurement function with significantly reduced size and improved precision, eliminating the need for large mechanical components.
2Adaptability or versatility
If a Helmholtz resonator viscometer is used for gas measurement, then gas viscosity can be measured, but the valid frequency section is limited to low frequency domain only
Solution Approach 1:
The patent employs dynamically tunable acoustic resonators whose resonant frequencies can be adjusted across a wide range. By making the resonant frequency variable rather than fixed, the system can adapt to measure viscosity at different frequencies (including high frequencies above 200 Hz), thereby expanding the frequency measurement range while maintaining measurement precision through active frequency tuning.
Solution Approach 2:
The patent changes the operating parameters of the acoustic resonators, specifically tuning the resonant frequency across a wide bandwidth. By adjusting frequency parameters and using multiple resonators with different characteristics, the system extends its valid frequency section from low frequency only to a broad spectrum including high frequencies, while maintaining measurement accuracy through parameter optimization.
3Quantity of substance
If a crystal resonant sensor viscometer is used, then viscosity can be measured with small liquid volume, but the device cannot measure gas and requires horizontal placement
Solution Approach 1:
The patent designs a universal viscometer that can measure both gas and liquid viscosity using the same acoustic resonator platform. By using acoustic wave propagation principles that work in both gas and liquid phases, and eliminating the need for gravity-dependent liquid distribution mechanisms, the device achieves multi-functionality across different fluid types while maintaining the advantage of requiring minimal fluid volume.
Solution Approach 2:
The patent replaces the gravity-dependent crystal resonant sensor mechanism with an acoustic wave-based measurement system. This substitution eliminates the need for horizontal placement and enables gas measurement capability, while maintaining the advantage of requiring minimal fluid volume through direct acoustic interaction with the fluid in the resonator chamber.
4Measurement precision
If a capillary tube viscometer is used, then liquid viscosity can be measured, but large volume of liquid (dozen to hundreds of ml) is required
Solution Approach 1:
The patent replaces the gravity-driven capillary tube mechanism with an acoustic resonator system. By using acoustic wave propagation and resonance phenomena, the device can measure liquid viscosity without relying on gravity-induced flow, thereby eliminating the need for large liquid volumes (dozen to hundreds of ml) and reducing the required sample volume to minimal amounts suitable for micro-scale measurement.
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 micro viscometer achieves accurate viscosity measurements with a small amount of fluid, extending the frequency domain and reducing errors, allowing for precise fluid analysis in both liquids and gases, with a compact size that overcomes previous size and frequency limitations.
Implementation Method 1
a first thin film (150) that vibrates with the fluid within the first chamber (120) and locates on the side of the first chamber (120); a second thin film (160) that vibrates with the fluid within the second chamber (130) and locates on the side of the second chamber (130)
Implementation Method 2
an actuating part (170) that applies vibration onto the fluid within the first chamber (120) by conducting vibration through the first thin film (150)
Data Source
AI summary
Disclosed is a micro viscometer comprising a body including an inlet where a fluid flows in, an outlet where the fluid flows out, a first chamber and a second chamber that is connected to the inlet and the outlet, respectively, a substrate and a cover that partition multiple micro channels that connect the first chamber and the second chamber; a first thin film that vibrates with the fluid within the first chamber and locates on the side of the first chamber; a second thin film that vibrates with the fluid within the second chamber and locates on the side of the second chamber; an actuating part that applies vibration onto the fluid within the first chamber by conducting vibration through the first thin film; a sensing part that senses vibration or pressure onto the fluid that transfers through the micro channels to the second thin film through vibration of the first thin film.