Method and apparatus for measuring thermophysical properties
AssigneeNational Institute of Advanced Industrial Science and Technology
InventorsHiromichi Watanabe, Tetsuya Baba
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Abstract
The present invention provides a method for measuring thermophysical properties that includes: rapid resistive self-heating of a specimen by using a heating current; emitting a light to the specimen heated by the rapid resistive self-heating of the specimen; measuring a temperature change of the specimen induced by emitting the light to the specimen; and deriving a thermal diffusivity of the specimen from the temperature change induced by emitting the light to the specimen.
Claims6
A method for measuring thermophysical properties that comprises the following sequential steps:
- rapid resistive self-heating of a specimen by using a heating current;
- adjusting the heating current to maintain the specimen at a target temperature;
- emitting a light to the specimen heated by the rapid resistive self-heating of the specimen while maintaining the heating current at the same value as that which maintained the specimen at a target temperature before emitting the light to the specimen;
- measuring a temperature change of the specimen induced by emitting the light to the specimen;
- deriving a thermal diffusivity of the specimen from the temperature change induced by emitting the light to the specimen;
- measuring a temperature of the specimen when the temperature of the specimen is held at a constant temperature before emitting the light to the specimen;
- an electric power that is supplied to the specimen when the temperature of the specimen is held at the constant temperature;
- and a temperature change of the specimen induced by the rapid resistive self-heating of the specimen;
- deriving a hemispherical total emissivity of the specimen from the temperature and the electric power;
- and
- deriving a specific heat capacity of the specimen from the hemispherical total emissivity and the temperature change induced by the rapid resistive self-heating of the specimen;
- wherein the temperature of the specimen is controlled under a feedback control so as to have the constant temperature until just before emitting the light to the specimen.
An apparatus for measuring thermophysical properties that comprises:
- a rapid resistive self heating member for rapid resistive self heating of a specimen by using a heating current;
- a system for maintaining the specimen at a constant temperature;
- a system for maintaining a constant heating current flow to the specimen;
- a light emission member for emitting a light to the specimen heated by the rapid resistive self-heating of the specimen;
- a temperature measuring member for measuring a temperature change induced by emitting the light to the specimen;
- and
- an analysis member for deriving a thermal diffiasivity of the specimen from the temperature change induced by emitting the light to the specimen;
- wherein:
- the analysis member farther derives a hemispherical total emissivity and a specific heat capacity of the specimen;
- the hemispherical total emissivity is derived from a temperature of the specimen when the temperature of the specimen is held at a constant temperature before emitting the light to the specimen;
- an electric power that is supplied to the specimen when the temperature of the specimen is held at the constant temperature;
- the specific heat capacity of the specimen is derived from the hemispherical total emissivity;
- a temperature change of the specimen induced by the rapid resistive self-heating of the specimen;
- and
- the temperature of the specimen is controlled under a feedback control so as to have the constant temperature until just before emitting the light to the specimen.
Dependencies are inferred from the claim text.