In nature, microscale hair-like projections called cilia are used ubiquitously for both sensing and motility. In this paper, biomimetic nanoscale cilia arrays have been fabricated through templated growth of Co in anodized aluminum oxide. The motion of arrays of Co cilia was then detected using magnetic sensors. These signals were used to prove the feasibility of two types of sensors: flow sensors and vibration sensors. The flow sensors were tested in a microfluidic channel. They showed the ability to detect flows from 0.5 ml/min to 6 ml/min with a signal to noise (SNR) of 44 using only 140 μW of power and no amplification. The vibration sensors were tested using a shake table in the low earthquake-like frequency range of 1-5 Hz. The vibration response was a mW signal at twice the frequency of the shake table.

Fabrication of BioInspired Inorganic Nanocilia Sensors

Flow Measurement Handbook: Conferences

World Federation of Societies of Anaesthesiologists

Calibration-Free Volume Flow Measurement Principle Based on Thermal Time-of-Flight (TToF)

Thermal flow measurement is currently based on the principle of heat energy displacement caused by a flowing fluid (mass flow measurement). The heat is induced by a continuous heating element immersed into the fluid. This kind of sensor is only applicable for fluids with known homogeneity properties [3].

Thermal signal behaviour for air flow measurements as fundamentals to Time-of-Flight

This communication reports on a numeric fluid dynamics simulation on a pipe flow model. The basic background is to deter- mine the velocity of a flowing fluid in a pipe by using the Thermal Time-of-Flight (TTOF) method on water. The visualisation of the temperature and velocity distribution in the pipe model is being carried out in order to enable proper design and optimisation of the TTOF sensor. The work is accomplished in two dimensional and three dimensional simulations. Transient simulations have been realised using the 2D simulation model. The flow velocity is calculated by means of the FFT-correlation technique. At several detection points the time- dependent temperarure signal is measured in a time period of ten seconds. The time delay of the output signals combined with the knowledge of the covered distances yields the flow velocity. In this work, a flow measurement technique in the velocity range 0.01 m/s ≤ vm ≤ 0.1 m/s is presented for water.

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Modelling Thermal Time-of-Flight Sensor for Flow Velocity Measurement

A system-theoretical model of an air flow sensor based on the principle of pulsed thermal Time-of-Flight (TTOF) is described. The region of interest (ROI) in the pipe flow is regarded as a linear time-invariant (LTI) system with an input and output signal. Based on the experimental results the simulation model is created and applied for analysis of different input signals and system's responses with respect to the flow velocity. Experimental and simulated results are compared in an air flow velocity range between 0.1 m/s and 0.7 m/s.

System-theoretical analysis and modeling of pulsed thermal Time-of-Flight flow sensor

The authors report on a flow measurement technique using the Thermal Time-of-Flight (TTOF) method. In this work the velocity of air flowing through a pipe was investigated. For this purpose a filament and several thermocouples were adopted. The filament served as a signal transmitter, which injected thermal pulses into the flowing fluid in the pipe. The generated thermal pulses propagated along the flowing direction towards the thermocouples. In three defined distances the injected thermal pulses were detected by three identical thermocouples, respectively. The time behaviour of the measured output signals was computed using the crosscorrelation process. The time delay of the output signals combined with the knowledge of the distances resulted in the flow velocity. In this work, a flow measurement technique in the velocity range of vmin = 0.01 m/s up to vmax = 1.20 m/s is presented considering laminar flow. Index Terms – thermal velocity measurement, pulsed heat injection, Time-of-Flight, thermocouples, cross-correlation.

E. Engelien

Papers

Calibration-Free Volume Flow Measurement Principle Based on Thermal Time-of-Flight (TToF)

Modelling Thermal Time-of-Flight Sensor for Flow Velocity Measurement

Thermal signal behaviour for air flow measurements as fundamentals to Time-of-Flight

System-theoretical analysis and modeling of pulsed thermal Time-of-Flight flow sensor

Evaluation on thermocouples for the Thermal Time-of-Flight flow measurement