Abstract

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 + 0.4τ00.47 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.

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call

Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.