An alternate to hot film flow sensors

1974 ◽  
Vol 45 (2) ◽  
pp. 300-301 ◽  
Author(s):  
F. Y. Sorrell ◽  
G. V. Sturm
Keyword(s):  
Film Flow ◽  
Flow Sensors ◽  
Hot Film

scholarly journals Sensitivity Enhancement of Silicon-on-Insulator CMOS MEMS Thermal Hot-Film Flow Sensors by Minimizing Membrane Conductive Heat Losses

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1860 ◽  
Author(s):  
Zahid Mehmood ◽  
Ibraheem Haneef ◽  
Syed Zeeshan Ali ◽  
Florin Udrea
Keyword(s):  
Thermal Conductivity ◽  
Thermal Resistance ◽  
Film Flow ◽  
Heat Losses ◽  
Silicon On Insulator ◽  
Conductive Heat ◽  
Circular Membrane ◽  
Flow Sensors ◽  
Cmos Mems ◽  
Hot Film

Minimizing conductive heat losses in Micro-Electro-Mechanical-Systems (MEMS) thermal (hot-film) flow sensors is the key to minimize the sensors’ power consumption and maximize their sensitivity. Through a comprehensive review of literature on MEMS thermal (calorimetric, time of flight, hot-film/hot-film) flow sensors published during the last two decades, we establish that for curtailing conductive heat losses in the sensors, researchers have either used low thermal conductivity substrate materials or, as a more effective solution, created low thermal conductivity membranes under the heaters/hot-films. However, no systematic experimental study exists that investigates the effect of membrane shape, membrane size, heater/hot-film length and M e m b r a n e (size) to H e a t e r (hot-film length) Ratio (MHR) on sensors’ conductive heat losses. Therefore, in this paper we have provided experimental evidence of dependence of conductive heat losses in membrane based MEMS hot-film flow sensors on MHR by using eight MEMS hot-film flow sensors, fabricated in a 1 µm silicon-on-insulator (SOI) CMOS foundry, that are thermally isolated by square and circular membranes. Experimental results demonstrate that: (a) thermal resistance of both square and circular membrane hot-film sensors increases with increasing MHR, and (b) conduction losses in square membrane based hot-film flow sensors are lower than the sensors having circular membrane. The difference (or gain) in thermal resistance of square membrane hot-film flow sensors viz-a-viz the sensors on circular membrane, however, decreases with increasing MHR. At MHR = 2, this difference is 5.2%, which reduces to 3.0% and 2.6% at MHR = 3 and MHR = 4, respectively. The study establishes that for membrane based SOI CMOS MEMS hot-film sensors, the optimum MHR is 3.35 for square membranes and 3.30 for circular membranes, beyond which the gain in sensors’ thermal efficiency (thermal resistance) is not economical due to the associated sharp increase in the sensors’ (membrane) size, which makes sensors more expensive as well as fragile. This paper hence, provides a key guideline to MEMS researchers for designing the square and circular membranes-supported micro-machined thermal (hot-film) flow sensors that are thermally most-efficient, mechanically robust and economically viable.

Investigations on the passivation of thin film flow sensors on flexible substrates

2007 ◽  
Author(s):  
U. Schmid ◽  
A. Ababneh ◽  
H. Seidel ◽  
R. Wagner ◽  
K. Bauer
Keyword(s):  
Thin Film ◽  
Film Flow ◽  
Flexible Substrates ◽  
Thin Film Flow ◽  
Flow Sensors

Study on the Dynamic Characteristics of Hot-Film Flow Sensor Based on the Sampling Air Channel

2014 ◽  
Vol 494-495 ◽  
pp. 197-200 ◽  
Author(s):  
Wei Liu ◽  
Li Feng Zhao
Keyword(s):  
Dynamic Response ◽  
Film Flow ◽  
Coupling Model ◽  
Response Characteristic ◽  
Flow Sensor ◽  
Intake Manifold ◽  
Film Sensor ◽  
Response Characteristics ◽  
Dynamic Response Characteristics ◽  
Hot Film

The hot-film flow sensors accurately measure the intake flow of engine. The air flow in the engine intake manifold is typical unsteady flow whose flow velocity changes remarkably. Therefore, the flow sensor should have a faster dynamic response characteristic. A thermosetting coupling model of a hot-film sensor was established based on CFD which is used to simulate dynamic response characteristics; the temperature field of the hot-film flow sensor probe was simulated. In addition, the dynamic response characteristics of the sensor simulated using the step pulse, and tested the dynamic response characteristics based on flow test equipment.

Comparison of the Dynamic Response of Calorimetric and Hot-Film Flow Transducers

2007 ◽  
Author(s):  
F. Kohl ◽  
R. Beigelbeck ◽  
S. Cerimovic ◽  
A. Talic ◽  
J. Schalko ◽  
...  
Keyword(s):  
Dynamic Response ◽  
Film Flow ◽  
Hot Film

scholarly journals Hot-film and calorimetric thermal air flow sensors realized with printed board technology

2016 ◽  
Vol 5 (2) ◽  
pp. 283-291 ◽  
Author(s):  
Thomas Glatzl ◽  
Samir Cerimovic ◽  
Harald Steiner ◽  
Almir Talic ◽  
Roman Beigelbeck ◽  
...  
Keyword(s):  
Air Conditioning ◽  
Printed Circuit Board ◽  
Cost Effective ◽  
Circuit Board ◽  
Experimental Characterization ◽  
Flow Sensors ◽  
Printed Circuit ◽  
Air Conditioning Systems ◽  
Hot Film ◽  
Good Agreement

Abstract. This paper addresses the development of flow sensors optimized for heating, ventilating, and air conditioning systems. The sensors are based on the printed circuit board technology facilitating robust, flexible (in terms of layout), and cost-effective devices. Two approaches for measuring fluid quantities like flow velocity over the whole cross section are investigated in this context. The first one relies on hot-film transduction and stands out for its simplicity, but also shows some severe limitations, which can be circumvented by the second approach based on calorimetric transduction. Supported by extensive numerical simulations, several sensor embodiments were investigated and fabricated. After experimental characterization, measurement and simulation results were compared, which turned out to be in good agreement.

scholarly journals Waterproof sensor system for simultaneous pressure and hot-film flow measurements

2017 ◽  
Vol 257 ◽  
pp. 208-215 ◽  
Author(s):  
Martin Schwerter ◽  
Monika Leester-Schädel ◽  
Andreas Dietzel
Keyword(s):  
Film Flow ◽  
Sensor System ◽  
Flow Measurements ◽  
Hot Film

Aircraft flight parameter detection based on a neural network using multiple hot-film flow speed sensors

2007 ◽  
Vol 16 (4) ◽  
pp. 1239-1245 ◽  
Author(s):  
Haiping Fei ◽  
Rong Zhu ◽  
Zhaoying Zhou ◽  
Jindong Wang
Keyword(s):  
Neural Network ◽  
Film Flow ◽  
Flow Speed ◽  
Aircraft Flight ◽  
Hot Film
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