Numerical and analytic study on the time-of-flight thermal flow sensor

Byon, Chan

doi:10.1016/j.ijheatmasstransfer.2015.05.011

Cited by 9 publications

(8 citation statements)

References 11 publications

(28 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In order to generate a thermal wave in the flowing gas, the temperature of the transmitter must change over time. In the thermal wave method, various types of electric current waveforms heating the wave transmitter are used: It may be a pulse signal [3][4][5][6], a sinu-soidal signal [1,2,[7][8][9][10] or-easiest to implement and most commonly used-a rectangular signal [11,12]. Other signals that have been used include a pseudo-stochastic signal [13], a signal composed of the sum of sinusoidal waveforms with various appropriately selected frequencies and amplitudes [14], and a rectangular multifrequency binary sequence (MBS) signal [15].…”

Section: Main Approaches To the Thermal Time-of-flight Methodsmentioning

confidence: 99%

“…In the direct method, the time of flight of the wave is determined on the basis of selected characteristic points in the time waveforms of the signals recorded by the detectors. The most frequently selected points are the beginning of the signal rise [ 17 ] or the maximum signal [ 5 , 10 ]. The correlation method consists of determining the time interval between the signals using the cross-correlation function [ 13 , 18 ].…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

A Semi-Empirical Approach to Gas Flow Velocity Measurement by Means of the Thermal Time-of-Flight Method

Sobczyk

Rachalski

Wodziak

2021

Sensors

View full text Add to dashboard Cite

This paper presents a method of measuring gas flow velocity based on the thermal time-of-flight method. The essence of the solution is an analysis of the time shift and the shape of voltage signals at the transmitter and at a temperature wave detector. The measurements used a probe composed of a wave transmitter and a detector, both in the form of thin tungsten wires. A rectangular signal was used at the wave transmitter. The time-of-flight of the wave was determined on the basis of the time shift of two selected characteristic points of the voltage waveform at the transmitter and the wave detector. To obtain the correct velocity indication, a correction in the form of a simple power function was applied. From the measurements performed, the relative uncertainty of the method was obtained, from approx. 4% of the measured value at an inflow velocity of 6.5 cm/s to 1% for an inflow velocity of 50 cm/s and higher.

show abstract

Section: Main Approaches To the Thermal Time-of-flight Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

A Semi-Empirical Approach to Gas Flow Velocity Measurement by Means of the Thermal Time-of-Flight Method

Sobczyk

Rachalski

Wodziak

2021

Sensors

View full text Add to dashboard Cite

show abstract

“…With the known hotwire driving frequency and comparing the sensing wire signal to the same, the spatial wavelength of the heat convection pattern was measured, and the air mean convection velocity was calculated. In recent years, quite a few excellent research works based on this concept have been published [ 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 ]. In these studies, the approach was also named pulsed anemometers.…”

Section: Thermal Time-of-flight Sensingmentioning

confidence: 99%

“…The heat wave propagation in the thermal time-of-flight sensing configuration observes the same physics for a thermal line source in a fluid. The total heat wave transfer includes both thermal diffusion and forced thermal convection, and the working principle can be expressed for energy conservation as below [ 29 , 33 , 39 , 40 ]:

where T (K) is the fluidic temperature, t (s) is the time, k (W m −1 K −1 ) is thermal conductivity, c (J kg −1 K −1 ) is thermal capacitance, and ρ (kg m −3 ) is the fluidic density. The heat wave Q (J) is a time-dependent value of either a modulated heat wave or a defined heat pulse.…”

Section: Thermal Time-of-flight Sensingmentioning

confidence: 99%

Micromachined Thermal Time-of-Flight Flow Sensors and Their Applications

Huang¹

2022

Micromachines

View full text Add to dashboard Cite

Micromachined thermal flow sensors on the market are primarily manufactured with the calorimetric sensing principle. The success has been in limited industries such as automotive, medical, and gas process control. Applications in some emerging and abrupt applications are hindered due to technical challenges. This paper reviews the current progress with micromachined devices based on the less popular thermal time-of-flight sensing technology: its theory, design of the micromachining process, control schemes, and applications. Thermal time-of-flight sensing could effectively solve some key technical hurdles that the calorimetric sensing approach has. It also offers fluidic property-independent data acquisition, multiparameter measurement, and the possibility for self-calibration. This technology may have a significant perspective on future development.

show abstract

“…Specifically, thermal flow sensors are widely investigated, due to their simple structure and low power consumption (Kuo et al, 2012). According to the thermal interaction between the sensors and the fluids, thermal flow sensor can be classified into three types: hot-film/hot-wire flow sensors (Comte-Bellot, 1976;Mailly et al, 2001), time-of-flight flow sensors (Byon, 2015), and calorimetric flow sensors (Kitsos et al, 2019). All types of micro thermal flow sensors can be easily implemented in CMOS processes thanks to their non-movable sensing structures.…”

Section: Introductionmentioning

confidence: 99%

A Nanoscale Hot-Wire Flow Sensor Based on CMOS-MEMS Technology

et al. 2022

View full text Add to dashboard Cite

In this paper, we proposed an ultrafast and nanoscale hot-wire flow (NHF) sensor implemented in a 0.18 µm complementary metal-oxide-semiconductor microelectromechanical system (CMOS-MEMS) technology. The nanoscale wire was released and reduced in thickness and width by an in-house developed post-CMOS fabrication process, hence the heat conduction loss is greatly suppressed, while the response time of the NHF sensor is significantly improved. Benefiting from the nano size of the hot-wire (a width of 622 nm), the NHF sensor exhibits an ultrafast response time of 30 µs (@ airflow velocity of 0 m/s), a wide flow range of 0–30 m/s, and a cut-off frequency of 21 kHz under the constant temperature (CT) mode. In addition, an equivalent circuit model (ECM) was established in PSPICE to predict the NHF sensor performance, and the theoretical simulation results were in good agreement with the experiment results.

show abstract

Numerical and analytic study on the time-of-flight thermal flow sensor

Cited by 9 publications

References 11 publications

A Semi-Empirical Approach to Gas Flow Velocity Measurement by Means of the Thermal Time-of-Flight Method

A Semi-Empirical Approach to Gas Flow Velocity Measurement by Means of the Thermal Time-of-Flight Method

Micromachined Thermal Time-of-Flight Flow Sensors and Their Applications

A Nanoscale Hot-Wire Flow Sensor Based on CMOS-MEMS Technology

Contact Info

Product

Resources

About