Kenari Shirin Azadi, Wiegerink Remco J, Sanders Remco G P, Lötters Joost C
Integrated Devices and Systems, University of Twente, 7522 NB Enschede, The Netherlands.
Bronkhorst High-Tech BV, 7261 AK Ruurlo, The Netherlands.
Micromachines (Basel). 2024 May 21;15(6):671. doi: 10.3390/mi15060671.
Among the different techniques for monitoring the flow rate of various fluids, thermal flow sensors stand out for their straightforward measurement technique. However, the main drawback of these types of sensors is their dependency on the thermal properties of the medium, i.e., thermal conductivity (), and volumetric heat capacity (ρcp). They require calibration whenever the fluid in the system changes. In this paper, we present a single hot wire suspended above a V-groove cavity that is used to measure and ρcp through DC and AC excitation for both pure gases and binary gas mixtures, respectively. The unique characteristic of the proposed sensor is its independence of the flow velocity, which makes it possible to detect the medium properties while the fluid flows over the sensor chip. The measured error due to fluctuations in flow velocity is less than ±0.5% for all test gases except for He, where it is ±6% due to the limitations of the measurement setup. The working principle and measurement results are discussed.
在监测各种流体流速的不同技术中，热流量传感器因其测量技术简单直接而脱颖而出。然而，这类传感器的主要缺点是它们依赖于介质的热特性，即热导率（）和体积热容（ρcp）。每当系统中的流体发生变化时，它们都需要进行校准。在本文中，我们展示了一种悬挂在V型槽腔上方的单根热线，该热线分别用于通过直流和交流激励来测量纯气体和二元气体混合物的和ρcp。所提出的传感器的独特特性是其与流速无关，这使得在流体流过传感器芯片时能够检测介质特性。除氦气外，所有测试气体因流速波动引起的测量误差均小于±0.5%，由于测量装置的限制，氦气的测量误差为±6%。本文讨论了其工作原理和测量结果。
