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

Glatzl, Thomas; Ćerimović, Samir; Steiner, Harald; Talic, Almir; Beigelbeck, Roman; Jachimowicz, A.; Sauter, Thilo; Keplinger, Franz

doi:10.5194/jsss-5-283-2016

Cited by 9 publications

(4 citation statements)

References 28 publications

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“…In addition, the heat transfer coefficient h ∞ relates to the flow speed U ∞ by the laminar boundary layer theory, as in Equation (3) or Equation ( 4), subject to a flat plate under the medium value of the Reynolds number flow [182]. Substituting Equation (4) into Equations ( 1) and ( 2) can correlate the temperature difference and the flow speed.…”

Section: Flow Sensor Designmentioning

confidence: 99%

Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

et al. 2022

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The complementary metal-oxide-semiconductor (CMOS) process is the main stream to fabricate integrated circuits (ICs) in the semiconductor industry. Microelectromechanical systems (MEMS), when combined with CMOS electronics to form the CMOS MEMS process, have the merits of small features, low power consumption, on-chip circuitry, and high sensitivity to develop microsensors and micro actuators. Firstly, the authors review the educational CMOS MEMS foundry service provided by the Taiwan Semiconductor Research Institute (TSRI) allied with the United Microelectronics Corporation (UMC) and the Taiwan Semiconductor Manufacturing Company (TSMC). Taiwan’s foundry service of ICs is leading in the world. Secondly, the authors show the new flow sensor integrated with an instrumentation amplifier (IA) fabricated by the latest UMC 0.18 µm CMOS MEMS process as the case study. The new flow sensor adopted the self-heating resistive-thermal-detector (RTD) to sense the flow speed. This self-heating RTD half-bridge alone gives a normalized output sensitivity of 138 µV/V/(m/s)/mW only. After being integrated with an on-chip amplifier gain of 20 dB, the overall sensitivity of the flow sensor was measured and substantially improved to 1388 µV/V/(m/s)/mW for the flow speed range of 0–5 m/s. Finally, the advantages of the CMOS MEMS flow sensors are justified and discussed by the testing results.

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Section: Flow Sensor Designmentioning

confidence: 99%

Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

et al. 2022

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“…In this case, temperature sensors arranged around the heater are needed for detection. Their temperature difference is a function of the flow velocity [9,10,11]. Time-of-flight (TOF) flow sensors measure the propagation of a heat pulse over a known distance between the heater and the temperature sensor located downstream of the heater [12,13,14].…”

Section: Introductionmentioning

confidence: 99%

“…In this case, temperature sensors arranged around the heater are needed for detection. Their temperature difference is a function of the flow velocity [9,10,11].…”

Section: Introductionmentioning

confidence: 99%

Development and Characterization of Thermal Flow Sensors for Non-Invasive Measurements in HVAC Systems

Ćerimović

Treytl

Glatzl

et al. 2019

Sensors

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We investigated non-invasive flow rate measurements in heating, ventilation, and air conditioning (HVAC) systems utilizing thermal transduction instead of commonly used ultrasonic techniques. The proposed thermal flow transduction comprises two temperature sensors and a heater, all mounted non-invasively on the outer surface of metal-pipes and, therefore, not disturbing the fluid flow inside. One temperature sensor measures the heater temperature, whereas the other one, mounted upstream of the heater, follows the fluid temperature for reference. The temperature difference (i.e., the heater excess temperature) depends on the fluid flow velocity and can be used to derive the mean volume flow inside the pipe. Experimental characterizations were conducted using two sensor prototypes. Beside output characteristics, other main issues such as dynamic behavior and noise density were investigated in detail. Special attention was paid to error compensation allowing measurements within a large range of fluid temperatures. Measurement results confirm the feasibility of this approach, however with some constraints regarding response time.

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“…In recent years, MEMS hot-film air flow sensor has been widely used in the fields of aerospace, automotive, biomedical, environmental monitoring, semiconductor, and domestic appliances due to its ability of indirect measurement of air mass flow via measurements of temperature changes and the characteristics of high accuracy, fast response, and low power consumption [1][2][3]. However, in practical applications, it is found that if the gas to be measured contains aerosol particles, oil mist, etc., the surface of the sensor chip will be contaminated, which affects the accuracy of the sensor.…”

Section: Introductionmentioning

confidence: 99%

Mechanism and Modeling of Contaminant Accumulation on Hot‐Film Air Flow Sensor

Yuan

Sun

2019

Mathematical Problems in Engineering

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Hot-film air flow sensors are now widely applied in many industrial fields. Their accuracy can be seriously affected when there are contaminants accumulated on the sensor chip. To predict the decrease of accuracy caused by contamination, the accumulation mechanism of contaminant particles on the surface of the sensor chip is studied in this paper. The adsorption process of particle is analyzed and a theoretical model of the cumulative thickness of the particles over time is established. A test platform for the particle accumulation is built and a long-term cumulative test is conducted. According to the tests, cumulative thickness of the particles increases while the growth rate slows over time. The results of the test fit those of the theoretical model. Various factors affecting the accumulation of contaminants are analyzed. The results indicate that the cumulative thickness of the particles increases along with the increase of the particle concentration, the particle charge, and the electric field strength on the chip surface but decreases along with the increase of the particle radius. The test results also show that the electrical force is the dominant reason of particle adsorption accumulation. By decreasing the electric field strength on the sensor surface, the cumulative thickness of the particles can be effectively reduced.

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

Cited by 9 publications

References 28 publications

Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

Foundry Service of CMOS MEMS Processes and the Case Study of the Flow Sensor

Development and Characterization of Thermal Flow Sensors for Non-Invasive Measurements in HVAC Systems

Mechanism and Modeling of Contaminant Accumulation on Hot‐Film Air Flow Sensor

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