An integrated pressure-flow sensor for correlation measurements in turbulent gas flows

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• 作者：Kä ; lvesten ; E. ; Stemme ; G. ; Vieider ; C. ; Lö ; fdahl ; L.
• 关键词：Flow sensors ; Pressure sensors ; Turbulence
• 刊名：Sensors and Actuators A: Physical
• 出版年：1996
• 出版时间：March 4, 1996
• 年：1996
• 卷：52
• 期：1-3
• 页码：51-58
• 全文大小：782 K

文摘

A new integrated pressure-flow sensor has been specially designed for measurements in turbulent gas flows. The pressure sensor is based on polysilicon diaphragm technology and the flow sensor on the gas cooling of a polyimide-insulated heated mass. With a pressure-sensor diaphragm area of 100 μm × 100 μm, a flow-sensor hot-chip area of 300 μm × 60 μm and an edge-to-edge distance of 100 μm between the different sensor areas, the smallest eddies in technically interesting turbulent flows can be resolved and measured. The pressure-sensor design shows a flat frequency response curve within ±2 dB between 10 Hz and 10 kHz with an acoustic sensitivity of 0.9 μV Pa⁻¹ for a supply voltage of 10 V. The flow sensor has a thermal response with a time constant of 7 ms and a response time of 25 μs when the sensor is operated at constant temperature using feedback electronics. The measured steady-state flow-sensor power dissipation in a turbulent wall boundary layer at an overtemperature of 100°C was P = 34 + 0.4_τ0^0.47 mW where τ₀ is the time-average flow-dependent wall shear stress. The integrated sensor has been used for simultaneous measurement of fluctuating pressure and wall shear stress in a turbulent boundary layer yielding pressure-wall shear stress correlation coefficients never previously presented.