SwePub
Sök i SwePub databas

  Utökad sökning

Träfflista för sökning "WFRF:(Kälvesten Edvard 1967 ) "

Sökning: WFRF:(Kälvesten Edvard 1967 )

  • Resultat 1-10 av 19
Sortera/gruppera träfflistan
   
NumreringReferensOmslagsbildHitta
1.
  •  
2.
  • Löfdahl, Lennart, 1948, et al. (författare)
  • An Integrated Silicon Based Pressure-Shear Stress Sensor for Turbulence Measurements
  • 1996
  • Ingår i: Advances in Turbulence VI (eds. Gavrilakis et al.), Kluwer, pp. 465-469..
  • Konferensbidrag (refereegranskat)abstract
    • An integrated silicon pressure-shear stress sensor has been designed, fabricated and tested in a turbulent wall-boundary layer. The piezoresisitve pressure sensor is based on a polysilicon diaphragm technology and the thermal shear stress sensor on the gas cooling of a polyimide insulated heated chip. The pressure sensor diaphragm area is 100 x 100 μm, the top area of the shear stress sensor hot chip is 300 x 60 μm and the edge-to-edge distance between the two areas is 100 μm. The measured steady-state power dissipation of the shear stress sensor in a turbulent wall-boundary layer at an over-temperature of 100 degrees Celsius was ___ where ___ is the time-average wall shear stress. The new integrated sensor has been applied for the simultaneous measurement of fluctuating pressure and shear stress in a flat plate boundary layer at a Reynolds number range of ___. Pressure-shear stress correlations coefficients were found between 0.40 and 0.50 for the parallel, and between 0.20 and 0.25 for the perpendicular configuration to the mean flow.
  •  
3.
  •  
4.
  • Kälvesten, Edvard, 1967, et al. (författare)
  • A Small-Size Microphone for Turbulence Measurements
  • 1995
  • Ingår i: Sensors and Actuators A. ; 45, s. 103-108
  • Tidskriftsartikel (refereegranskat)abstract
    • For the first time a silicon microphone specially designed for measurements in turbulent gas flows has been fabricated and tested. The new design, based on surface-micromachining techniques, has a very small pressure-sensitive polysilicon diaphragm of 100 μm side length and 0.4 μm thickness with polysilicon piezoresistive strain gauges. The small diaphragm makes it possible to resolve and measure the pressure fluctuations of the smallest eddies in a turbulent flow. In order to achieve a sufficiently high acoustic pressure sensitivity, a relatively deep (3 μm) cavity is formed below the diaphragm by using the sacrificial-layer etching technique. A special vent channel is designed to give an equalization of the static air pressure between the cavity and the ambient without degrading the dynamic pressure response of the microphone. The device has a very flat frequency-response curve within ±2 dB between 10 Hz and 10 kHz and an acoustic sensitivity of 0.9 μV Pa−1 for a supply voltage of 10 V. It has been shown that the new sensor fulfils the requirements for pressure measurements in turbulence. The microphone frequency response has been calculated using an electrical analogy. Comparisons with experimental data are presented.
  •  
5.
  • Kälvesten, Edvard, 1967, et al. (författare)
  • An Integrated Pressure-Velocity Sensor for Correlation Measurements in Turbulent Gas Flows
  • 1996
  • Ingår i: Sensors and Actuators A. ; :52, s. 51-58
  • Tidskriftsartikel (refereegranskat)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.
  •  
6.
  • Kälvesten, Edvard, 1967, et al. (författare)
  • An Integrated Pressure-Velocity Sensor for Correlation Measurements in Turbulent Gas Flows
  • 1995
  • Ingår i: Transducers´95- Eurosensors 9, Stockholm.
  • Konferensbidrag (refereegranskat)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 polymide-insulated heated mass. With a pressure-sensor diaphragm area of 100 μm x 100 μm, a flow-sensor hot-chip area of 300 μm x 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 ___ 2dB between 10 Hz and 10 kHz with an acoustic sensitivity of ___ 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 degrees Celsius was ___ mW where ___ is the time-average flow-dependant wall shear stress. The integrated sensor has been used for simultaneous measurements of fluctuating pressure and wall shear stress in a turbulent boundary layer yielding pressure-wall shear stress correlation coefficients never previously presented.
  •  
7.
  • Kälvesten, Edvard, 1967, et al. (författare)
  • Analytical Characterisation of Piezoresistive Square Diaphragm Silicon Microphone
  • 1996
  • Ingår i: Sensors and Materials. ; 8, s. 113-136
  • Tidskriftsartikel (refereegranskat)abstract
    • An analytical energy method has been used to derive the characteristics of a square-diaphragm piezoresistive silicon microphone. All relevant mechanical and acoustical effects of the sensor characteristics are included in the method. First, the energy contributions are calculated and then identified with equivalent acoustical impedances. These equivalent impedances are used in the electrical analogy. The method is applied to a piezoresistive microphone having a square diaphragm over its cavity. A special vent channel which equalizes the static air pressure between the cavity and the ambient has been included in the model. Good agreement between the theoretical analysis and experimental data on fabricated microphones was obtained.
  •  
8.
  • Kälvesten, Edvard, 1967, et al. (författare)
  • Small Piezoresistive Silicon Microphones specially Designed for the Characterization of Turbulent Gas
  • 1994
  • Ingår i: Eurosensor 8, Toulouse, September 25-28.
  • Konferensbidrag (refereegranskat)abstract
    • For the first time silicon microphone specially designed for measurements in turbulence gas flows has been fabricated and tested. The new design, based on surface-micromachining techniques, has a very small pressure-sensitive ploy silicon diaphragm of 100 um side length and 4.0 um thickness with poly silicon piezoresistive strain gauges. The small diaphragm makes it possible to resolve and measure the pressure fluctuations of the smallest eddies in a turbulent flow. In order the achieve a sufficiently high acoustic pressure fluctuations of the smallest eddies in a turbulent flow. In order to achieve a sufficiently high acoustic pressure sensitivity, a relatively deep (3um) cavity is formed below the diaphragm by using the sacrificial-layer etching technique. A special vent channel is designed to give an equalization of the static air pressure between the cavity and the ambient without degrading the dynamic pressure response of the microphone. The device has a very flat frequency response curve within _+ 2 dB between 10 Hz and 10 kHz and an acoustic sensitivity of 0.9u V Pa -1 for a supply voltage of 10 V. It has shown that the new sensor fulfils the requirements for pressure measurements in turbulence. The microphone frequency response has been calculated using an electrical analogy. Comparisons with experimental data are presented.
  •  
9.
  • Kälvesten, Edvard, 1967, et al. (författare)
  • Small Piezoresistive Silicon Microphones Specially Designed for the Characterization of Turbulent Gas Flows
  • 1995
  • Ingår i: Sensors and Actuators A. ; 46, s. 151-155
  • Tidskriftsartikel (refereegranskat)abstract
    • Piezoresistive microphones have been designed and fabricated using surface micromachining technology. The acoustic sensors, which are specially designed for turbulence gas flow measurements, are fabricated with the very small diaphragm side lengths of 100 and 300 um. An expression for the dynamic pressure sensitivity is derived where the diaphragm bending forces, the tensile built-in stain force, as well as the fluid compressibility forces are considered. The acoustic sensitivity’s, which are in the range 0.3-0.9 u V/Pa for a supply voltage of 10 V, are compared with the calculated values, showing good agreement. The frequency response is falt up to 10 kHz within -+ 2dB. The ability to measure the smallest pressure eddies in a turbulent boundary layer is verified and compared for different diaphragm sizes.
  •  
10.
  •  
Skapa referenser, mejla, bekava och länka
  • Resultat 1-10 av 19

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy