Appraisal of a hot-wire temperature compensation technique for velocity measurements in non-isothermal flows

1999 ◽  
Vol 42 (16) ◽  
pp. 3097-3102 ◽  
Author(s):  
S.J. Ball ◽  
S. Ashforth-Frost ◽  
K. Jambunathan ◽  
C.F. Whitney
Keyword(s):  
Temperature Compensation ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Wire Temperature ◽  
Compensation Technique ◽  
Isothermal Flows

scholarly journals Two Wire Sensor for Measuring the Velocity of Non-Isothermal Flows

Sensors ◽  
2021 ◽  
Vol 22 (1) ◽  
pp. 162
Author(s):  
Katarzyna Socha ◽  
Paweł Jamróz
Keyword(s):  
Flow Velocity ◽  
High Temperatures ◽  
Experimental Verification ◽  
Cross Correlation ◽  
Static Characteristics ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Resistance Thermometers ◽  
Isothermal Flows ◽  
Wire Resistance

Changes in the temperature of the medium significantly affect the static characteristics of hot-wire anemometry measuring wires, which causes errors in the results of flow velocity measurements. High temperatures of the medium make it necessary to additionally heat the sensor to even higher temperatures, which may lead to its damage due to wire burnout. The article proposes a solution to the problem of measuring the flow velocity in conditions of non-stationary temperatures with the use of the method of cross-correlation of signals from two-wire resistance thermometers. The main assumptions of the method and its experimental verification were presented.

A Temperature Compensation Technique for a Dynamic Amplifier in Pipelined-SAR ADCs

2018 ◽  
Vol 1 (1) ◽  
pp. 10-13 ◽  
Author(s):  
Minglei Zhang ◽  
Kyoohyun Noh ◽  
Xiaohua Fan ◽  
Edgar Sanchez-Sinencio
Keyword(s):  
Temperature Compensation ◽  
Compensation Technique

Development of a CFD-based simulation model and optimization of thermal diffusion column: application on noble gas separation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hamed Eghbalahmadi ◽  
Parissa Khadiv-Parsi ◽  
Seyed Mohammad Ali Mousavian ◽  
Mohammad Hosein Eghbal Ahmadi
Keyword(s):  
Experimental Data ◽  
Thermal Diffusion ◽  
Noble Gas ◽  
Target Function ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Hot Wire ◽  
Wire Temperature ◽  
Diffusion Column ◽  
Performance Effects

Abstract In this study, numerical simulations were carried out to investigate the separation of the helium-argon gas mixture by thermal diffusion column. This research determined the significant parameters and their effects on the process performance. Effects of feed flow rate, cut ratio, and hot wire temperature in a 950 mm height column with an inner tube of 9.5 mm radius were examined through the simulation of the thermal diffusion column. For minimizing the number of simulations and obtaining the optimum operating conditions, response surface methodology (RSM) was used. Analysis of separative work unit (SWU) values as a target function for helium-argon separation clearly showed that the maximum amount of SWU in thermal diffusion column was achieved, when hot wire temperature increased as large as technically possible, and the feed rate and cut ratio were equal to 55 Standard Cubic Centimeters per Minute (SCCM) and 0.44, respectively. Finally, the SWU value in optimum conditions was compared with the experimental data. Results illustrated that the experimental data were in good agreement with simulation data with an accuracy of about 90%.

scholarly journals Simplified Calibration Method for Constant-Temperature Hot-Wire Anemometry

2020 ◽  
Vol 10 (24) ◽  
pp. 9058
Author(s):  
Hidemi Takahashi ◽  
Mitsuru Kurita ◽  
Hidetoshi Iijima ◽  
Seigo Koga
Keyword(s):  
Boundary Layer ◽  
Flow Velocity ◽  
Constant Temperature ◽  
Calibration Method ◽  
Large Temperature ◽  
Velocity Data ◽  
Hot Wire ◽  
Temperature Variations ◽  
Wire Temperature ◽  
Hot Wire Anemometry

This study proposes a unique approach to convert a voltage signal obtained from a hot-wire anemometry to flow velocity data by making a slight modification to existing temperature-correction methods. The approach was a simplified calibration method for the constant-temperature mode of hot-wire anemometry without knowing exact wire temperature. The necessary data are the freestream temperature and a set of known velocity data which gives reference velocities in addition to the hot-wire signal. The proposed method was applied to various boundary layer velocity profiles with large temperature variations while the wire temperature was unknown. The target flow velocity was ranged between 20 and 80 m/s. By using a best-fit approach between the velocities in the boundary layer obtained by hot-wire anemometry and by the pitot-tube measurement, which provides reference data, the unknown wire temperature was sought. Results showed that the proposed simplified calibration approach was applicable to a velocity range between 20 and 80 m/s and with temperature variations up to 15 °C with an uncertainty level of 2.6% at most for the current datasets.

Digitalization of High Accuracy Thermo-Anemometer for Heat Flux Measurement in Stratified Flow

2011 ◽  
Author(s):  
Shunichi Sanae ◽  
Katsuhisa Ohba
Keyword(s):  
Heat Flux ◽  
Temperature Dependence ◽  
Simultaneous Measurement ◽  
Temperature Compensation ◽  
Flux Measurement ◽  
Stratified Flow ◽  
High Accuracy ◽  
Velocity Measurements ◽  
First Order ◽  
Field Programmable

In this study, the high-accuracy thermo-anemometer was developed to execute simultaneous measurement of temperature and velocity by employing Field Programmable Gate Array (FPGA) devices. A cold-wire temperature sensor has first-order lags due to thermal time constants, that means that a phase compensation is essential to measure temperature fluctuations with high frequency. The digital filter comprised the exact first-order lead characteristics was realized by the bilinear s-z transformation. It was verified that the temperature signals were appropriately compensated with an uncertainty of less than ±3.9% in frequency up to 10 kHz. For velocity measurements, a temperature compensation is indispensable owing to velocity and temperature dependence of response of a hot-wire anemometer in thermally stratified flow fields. The accuracy of the velocity measurements at high temperature was improved with the strict algorithm of the temperature compensation calculation incorporating the temperature dependence of the thermal properties of the air. The high-accuracy velocity measurement was realized within the accuracy of ±1.6% in the temperature range of 1.5 times as wide as that of the previous analog based system. The simultaneous measurement system for temperature and velocity was applicable to measure heat flux in thermally stratified flows.

Turbulent Flow Over a Flat Plate Downstream of a Finite Height Perforated Plate

2014 ◽  
Vol 137 (2) ◽  
Author(s):  
F. Fouladi ◽  
P. Henshaw ◽  
D. S.-K. Ting
Keyword(s):  
Turbulent Flow ◽  
Flat Plate ◽  
Short Distance ◽  
Free Stream ◽  
Perforated Plate ◽  
Leading Edge ◽  
Grid Turbulence ◽  
Hot Wire ◽  
Velocity Measurements ◽  
Finite Height

An experimental investigation was carried out to study the turbulent flow over a flat plate in a wind tunnel. The turbulence was generated by a plate with diamond-shaped perforations mounted perpendicular to and on the leading edge of the flat plate. Unlike conventional grid turbulence studies, this perforated plate had a finite height, and this height was explored as a key independent parameter. Instantaneous velocity measurements were performed with a 1D hot-wire anemometer to reveal the behavior of the flow a short distance downstream of the perforated plate (X/D = 10–30). Different perforated plate heights (H = 3, 7, 11 cm) and free stream velocities (U = 4.5, 5.5, 6.5 m/s) have been studied.

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