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Metal-on-polymer shear stress sensor: Analysis and experiment
Abstract
A hot-film sensor, a metal-on-polymer shear stress sensor, is studied in air flow mounted on plexiglass and mounted on steel. Experimental measurements on the hot-film response were taken in steady and unsteady air flow. Numerical calculations were carried out for steady and unsteady conjugate heat transfer from the hot-film sensor with analysis for three bodies (air, hot film and polymer substrate). The numerical method is called the unsteady surface element (USE) method. For steady flow, the new theory agrees well with the experimental data in the sensitivity of heat transfer to shear stress: the total heat loss through the hot-film sensor versus one-third power of shear stress in dimensionless parameters is presented for both hot-film sensors glued on the plexiglass and the steel plate. The sensor mounted on steel has a much lower sensitivity to air flow compared to the hot-film sensor glued to plexiglass. The constant-current response of the hot-film sensor is calculated by subjecting the hot-film to a unit step heat input. The numerical results for the hot-film sensor temperature agree with the analytical solution at early times. The numerical results also indicate that the average temperature rises faster for a thin-metal sensor than for a thick-metal sensor because the thin sensor has less thermal mass involved in the heat transfer. The USE method combined with an inverse method contributes to the new theory available for anemometer simulation and velocity gradient simulation. The amplitude response of the hot-film sensor is investigated to improve an agreement between the experimental data and the numerically simulated data with amplitude correction by an amplitude ratio. The phase lag response is also investigated and the results show that the sensor phase lag response increases with increasing flow frequencies used in this research.
Subject Area
Mechanical engineering
Recommended Citation
Park, Chong Hwan, "Metal-on-polymer shear stress sensor: Analysis and experiment" (1994). ETD collection for University of Nebraska-Lincoln. AAI9425300.
https://digitalcommons.unl.edu/dissertations/AAI9425300