Unsteady heat film transfer from a thick hot-film sensor

10.2514/3.615 ◽  
1994 ◽  
Vol 8 (4) ◽  
pp. 797-799 ◽  
Author(s):  
Chong H. Park ◽  
Kevin D. Cole
Keyword(s):  
Film Sensor ◽  
Film Transfer ◽  
Hot Film ◽  
Hot Film Sensor

Localization of Flow Separation and Transition Over a Pitching NACA0012 Airfoil at Transitional Reynolds Numbers Using Hot-Films

2015 ◽  
Vol 137 (12) ◽  
Author(s):  
Allison Poels ◽  
Daniel Rudmin ◽  
Azemi Benaissa ◽  
Dominique Poirel
Keyword(s):  
Reynolds Numbers ◽  
Correlation Technique ◽  
Film Sensor ◽  
Pitching Airfoil ◽  
Eddy Simulation ◽  
Naca0012 Airfoil ◽  
Large Eddy ◽  
Sensor Signals ◽  
Hot Film ◽  
Hot Film Sensor

Separation and transition of flow over a pitching airfoil at transitional Reynolds Number are analyzed experimentally. The method is based on a windowed correlation between hot-film sensor signals taken simultaneously or synchronized based on the airfoil pitch angle. A comparison with large eddy simulation (LES) simulation obtained in the same conditions is presented and discussed. Our results agree very well with the LES data for the separation location during the pitch-up. For the pitch-down, the results show differences with the LES. However, when the LES data are analyzed with the same correlation technique, the results are in a better agreement.

Carbon Nanotube Thermal Probe Using Platinum Nano Hot-Film

2009 ◽  
Author(s):  
Koji Takahashi ◽  
Jun Hirotani ◽  
Satoshi Kai ◽  
Tatsuya Ikuta
Keyword(s):  
Carbon Nanotube ◽  
Contact Point ◽  
Atmospheric Condition ◽  
Thermal Probe ◽  
Film Sensor ◽  
Thermal Sensing ◽  
Water Absorption Effect ◽  
Hot Film ◽  
Air Conduction ◽  
Hot Film Sensor

This paper reports on a thermal probe using a carbon nanotube (CNT) on a platinum hot-film. CNT probe is expected to breakthrough the limitations of the existing ones owing to its unique characteristics but no practical thermal device has been fabricated yet. In order to explore the mechanisms of heating and measuring the smaller region than 10nm, we applied our recently developed sensor coupled with CNT, which consists of a suspended platinum film of 40nm × 500nm × 10micrometer. The principle of this probe as heater and sensor is explained, based on one dimensional heat conduction. Fabrication process using MEMS technique is also introduced, especially for a couple of critical techniques. One is to fabricate the nano sensor on an edge of the sensor substrate. The other is to bond a CNT on the suspended hot-film sensor. A CNT thermal probe using a multi-walled CNT of 70nm diameter and ca. 10 micrometers length is successfully fabricated. Its performances are tested in vacuum environment as to eliminate the presence of in-air conduction effect and water absorption effect around the contact point, which work for heat transport dominantly in atmospheric condition and degrade the spatial resolution. Our CNT probe showed a clear and reliable signal in vacuum and its sensitivity available for nanoscale thermal sensing and heating is confirmed.

215 Development of micro-fabricated hot-film sensor by MEMS and study on its validation of the wall shear stress fluctuation measurement

2014 ◽  
Vol 2014.63 (0) ◽  
pp. _215-1_-_215-2_
Author(s):  
Takuya SAWADA ◽  
Osamu TERASHIMA ◽  
Yasuhiko SAKAI ◽  
Kouji Nagata ◽  
Mitsuhiro SHIKIDA ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Film Sensor ◽  
Stress Fluctuation ◽  
Wall Shear ◽  
Hot Film ◽  
Fluctuation Measurement ◽  
Hot Film Sensor

A Technique for the Measurement of Wall Shear Stress Based on Micro Fabricated Hot-Film Sensor

2013 ◽  
Author(s):  
Takuya Sawada ◽  
Osamu Terashima ◽  
Yasuhiko Sakai ◽  
Kouji Nagata ◽  
Mitsuhiro Shikida ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Turbulent Flows ◽  
Temporal Resolution ◽  
Large Scale ◽  
High Temporal Resolution ◽  
Film Sensor ◽  
Wall Shear ◽  
Hot Film ◽  
Hot Film Sensor

The objective of this study is to establish a technique for accurately measuring the wall shear stress in turbulent flows using a micro-fabricated hot-film sensor. Previously, we developed a hot-film sensor with a flexible polyimide-film substrate. This sensor can be attached to curved walls and be used in various situations. Furthermore, the sensor has a 20-μm-wide, heated thin metal film. However, the temporal resolution of this hot-film sensor is not very high owing to its substrate’s high heat capacity. Consequently, its performance is inadequate for measuring the wall shear stress “fluctuations” in turbulent flows. Therefore, we have developed another type of hot-film sensor in which the substrate is replaced with silicon, and a cavity has been introduced under the hot-film for reducing heat loss from the sensor and achieving high temporal resolution. Furthermore, for improving the sensor’s spatial resolution, the width of the hot-film is decreased to 10 μm. The structure of the hot-film’s pattern and the flow-detection mechanism are similar to those of the previous sensor. Experimental results show that new hot-film sensor works as expected and has better temporal resolution than the previous hot-film sensor. As future work, we will measure the wall shear stress for a turbulent wall-jet and discuss the relationship between a large-scale coherent vortex structure and wall shear stress based on data obtained using the new hot-film sensor.

scholarly journals On the measurement of wall shear stress with a patch-type micro-fabricated hot-film sensor

2014 ◽  
Vol 9 (3) ◽  
pp. JFST0029-JFST0029 ◽  
Author(s):  
Takuya SAWADA ◽  
Osamu TERASHIMA ◽  
Yasuhiko SAKAI ◽  
Kouji NAGATA ◽  
Mitsuhiro SHIKIDA ◽  
...  
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Film Sensor ◽  
Patch Type ◽  
Wall Shear ◽  
Hot Film ◽  
Hot Film Sensor

scholarly journals Super Sonic Flow Measurement around the Cone Like Model using Hot Film Sensor(2)

1995 ◽  
Vol 15 (Supplement2) ◽  
pp. 7-10
Author(s):  
Takashi HOKARI ◽  
Toshikazu KUNIKYO ◽  
Futoshi IDA ◽  
Ikuhisa MIZUTA ◽  
Kaoru CHIBA ◽  
...  
Keyword(s):  
Flow Measurement ◽  
Film Sensor ◽  
Sonic Flow ◽  
Hot Film ◽  
Hot Film Sensor

Flight evaluation of a stagnation detection hot-film sensor

1992 ◽  
Author(s):  
MICHAEL SCOTT ◽  
NATALE STRAIN ◽  
CYNTHIA LEE
Keyword(s):  
Film Sensor ◽  
Hot Film ◽  
Hot Film Sensor

scholarly journals Heat Transfer Characteristics of Swirling Impinging Jets

2010 ◽  
Author(s):  
Karl J. Brown ◽  
Tim Persoons ◽  
Darina B. Murray
Keyword(s):  
Heat Transfer ◽  
Thermal Imaging ◽  
High Heat ◽  
Impinging Jets ◽  
Transfer Coefficients ◽  
Film Sensor ◽  
Heat Transfer Coefficients ◽  
High Heat Transfer ◽  
Hot Film ◽  
Hot Film Sensor

Impinging jets are well renowned for their abilities to achieve significantly high heat transfer coefficients. It has been found in previous studies that the incorporation of a swirl in the flow can enhance heat transfer but it can also decrease it. The objective of this research is to discover the defining characteristics of swirling impinging jets and to find an optimal swirl geometry for enhancing the heat transfer of the system. Using thermal imaging and hot film sensor techniques the heat transfer distribution of the swirling jet is examined in the context of the flow field; heat flux fluctuations at the impinging surface are investigated also.

0203 Measurement of wall shear stress with a micro hot film sensor

2015 ◽  
Vol 2015 (0) ◽  
pp. _0203-1_-_0203-2_
Author(s):  
Sora MURAMATSU ◽  
Koji IWANO ◽  
Yasuhiko SAKAI ◽  
Yasumasa ITO ◽  
Mitsuhiro SHIKIDA
Keyword(s):  
Shear Stress ◽  
Wall Shear Stress ◽  
Film Sensor ◽  
Wall Shear ◽  
Hot Film ◽  
Hot Film Sensor
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