Huang, J. B. and Jiang, F. K. and Tai, Y. C. and Ho, C. M. (1999) A micro-electro-mechanical-system-based thermal shear-stress sensor with self-frequency compensation. Measurement Science and Technology, 10 (8). pp. 687-696. ISSN 0957-0233. http://resolver.caltech.edu/CaltechAUTHORS:HUAmst99
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By applying the micro-electro-mechanical-system (MEMS) fabrication technology, we developed a micro-thermal sensor to measure surface shear stress. The heat transfer from a polysilicon heater depends on the normal velocity gradient and thus provides the surface shear stress. However, the sensitivity of the shear-stress measurements in air is less than desirable due to the low heat capacity of air. A unique feature of this micro-sensor is that the heating element, a film 1 µm thick, is separated from the substrate by a vacuum cavity 2 µm thick. The vacuum cavity prevents the conduction of heat to the substrate and therefore improves the sensitivity by an order of magnitude. Owing to the low thermal inertia of the miniature sensing element, this shear-stress micro-sensor can provide instantaneous measurements of small-scale turbulence. Furthermore, MEMS technology allows us make multiple sensors on a single chip so that we can perform distributed measurements. In this study, we use multiple polysilicon sensor elements to improve the dynamic performance of the sensor itself. It is demonstrated that the frequency-response range of a constant-current sensor can be extended from the order of 100 Hz to 100 kHz.
|Additional Information:||Copyright © Institute of Physics and IOP Publishing Limited 1999. Received 2 February 1999, in final form 29 April 1999, accepted for publication 5 May 1999. Print publication: Issue 8 (August 1999). This work is supported by an AFOSR-URI contract.|
|Subject Keywords:||MEMS shear-stress sensor, micro-machine technologies, flow sensing|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Archive Administrator|
|Deposited On:||25 Sep 2007|
|Last Modified:||26 Dec 2012 09:43|
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