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Analysis of Temperature Compensating Circuits for Hot-Wires and Hot-Films.

ADA050080

Publication Date	1977
Personal Author	Drubka, R. E.; Tan-Atichat, J.; Nagib, H. M.
Page Count	38
Abstract	A scheme utilizing a temperature probe immersed in the working fluid to compensate for the dependence of hot-wire (or hot-film) velocity calibration on ambient temperature variations is analyzed. To achieve compensation, only properties of the anemometer bridge, the velocity and temperature probes need to be known. The scheme provides means for incorporating the temperature compensation a priori to conducting the experiments, without the need for temperature calibration. Experiments were conducted, using tungsten hot-wires in air, to check the performance of the analysis and to verify some of the assumptions that were made. For typical probes, with an ambient temperature increase of 20 C, maximum error in the indicated velocity of 1% or less can be achieved. (Author)
Keywords	Hot wire anemometers Fluid flow Circuit analysis Compensation Temperature sensitive elements Temperature coefficients Thermistors Velocity Flowmeters Errors Computer programs Least squares method Tungsten Temperature measuring instruments
Source Agency	Non Paid ADAS
NTIS Subject Category	46B - Fluid Mechanics
Corporate Authors	Illinois Inst of Tech Chicago Dept of Mechanics Mechanical and Aerospace Engineering
Document Type	Technical Report
Title Note	Interim technical rept. 1 Jan 76-1 Jun 77.
NTIS Issue Number	197810
Contract Number	F44620-76-C-0062

Analysis of Temperature Compensating Circuits for Hot-Wires and Hot-Films.

Analysis of Temperature Compensating Circuits for Hot-Wires and Hot-Films.
ADA050080

Publication Date	1977
Personal Author	Drubka, R. E.; Tan-Atichat, J.; Nagib, H. M.
Page Count	38
Abstract	A scheme utilizing a temperature probe immersed in the working fluid to compensate for the dependence of hot-wire (or hot-film) velocity calibration on ambient temperature variations is analyzed. To achieve compensation, only properties of the anemometer bridge, the velocity and temperature probes need to be known. The scheme provides means for incorporating the temperature compensation a priori to conducting the experiments, without the need for temperature calibration. Experiments were conducted, using tungsten hot-wires in air, to check the performance of the analysis and to verify some of the assumptions that were made. For typical probes, with an ambient temperature increase of 20 C, maximum error in the indicated velocity of 1% or less can be achieved. (Author)
Keywords	Hot wire anemometers Fluid flow Circuit analysis Compensation Temperature sensitive elements Temperature coefficients Thermistors Velocity Flowmeters Errors Computer programs Least squares method Tungsten Temperature measuring instruments
Source Agency	Non Paid ADAS
NTIS Subject Category	46B - Fluid Mechanics
Corporate Authors	Illinois Inst of Tech Chicago Dept of Mechanics Mechanical and Aerospace Engineering
Document Type	Technical Report
Title Note	Interim technical rept. 1 Jan 76-1 Jun 77.
NTIS Issue Number	197810
Contract Number	F44620-76-C-0062