A high-temperature transient hot-wire thermal conductivity apparatus for fluids
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چکیده
منابع مشابه
A High-Temperature Transient Hot-Wire Thermal Conductivity Apparatus for Fluids
A new apparatus for measuring both the thermal conductivity and thermal diffusivity of fluids at temperatures from 220 to 775 K at pressures to 70 MPa is described. The instrument is based on the step-power-forced transient hot-wire technique. Two hot wires are arranged in different arms of a Wheatstone bridge such that the response of the shorter compensating wire is subtracted from the respon...
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A transient hot-wire apparatus was used to measure the thermal conductivity of argon with both steady-state and transient methods. The effects of wire diameter, eccentricity of the wire in the cavity, axial conduction, and natural convection were accounted for in the analysis of the steady-state measurements. Based on measurements on argon, the relative uncertainty at the 95 % level of confiden...
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A mathematical model is presented for a new-generation guarded-hot-plate apparatus to measure the thermal conductivity of insulation materials. This apparatus will be used to provide standard reference materials for greater ranges of temperature and pressure than have been previously available. The apparatus requires precise control of 16 interacting heated components to achieve the steady temp...
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The ability of a thermal anemometry system to accurately measure unsteady fluid velocity depends on the electrical control system as well as the thermal properties of the sensor. The present work is a numerical study of the thermal transient response of a hot-wire. A conventional constant temperature anemometer with an ideal feedback amplifier as well as a pulse width modulated system were used...
متن کاملAlgorithm to optimize transient hot-wire thermal property measurement.
The transient hot-wire method has been widely used to measure the thermal conductivity of fluids. The ideal working equation is based on the solution of the transient heat conduction equation for an infinite linear heat source assuming no natural convection or thermal end effects. In practice, the assumptions inherent in the model are only valid for a portion of the measurement time. In this st...
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ژورنال
عنوان ژورنال: Journal of Research of the National Institute of Standards and Technology
سال: 1991
ISSN: 1044-677X
DOI: 10.6028/jres.096.014