Double-probe thermal pulse thermal characteristic measuring system capable of calibrating probe interval in situ and method

Abstract

The invention discloses a double-probe thermal pulse thermal characteristic measuring system capable of calibrating the probe interval in situ by itself and a method based on the system. By means of the system and the method, thermal characteristic parameter measurement errors caused by changes of the probe interval can be reduced. The system comprises a heating probe, a base, a heating device, a data processing device and at least one temperature probe, wherein the base is used for fixing the heating probe and the temperature probes; a heating wire is arranged in the heating probe, the ratio of the length to the inner diameter of the heating probe is larger than a preset numerical value, and the heating probe conducts heating through the heating device; at least three temperature measuring elements are arranged in each temperature probe in the axial direction; the data processing device is connected with temperature measuring elements and used for obtaining temperature response data collected by the temperature measuring elements after the heating probe and the temperature probes are inserted into a substance to be measured, obtaining the actual interval between each temperature measuring element and the heating probe according to the temperature response data and obtaining thermal characteristic parameters of the substance to be measured through fitting according to the actual interval.

Description

technical field [0001] The invention relates to the technical field of thermal characteristic measurement, in particular to a dual-needle thermal pulse thermal characteristic measurement system capable of in-situ self-correcting probe spacing and a measurement method based on the system. Background technique [0002] At present, the single-needle thermal pulse method and the double-needle thermal pulse method are widely used to measure the thermal properties of materials such as soil, rock, food, and combustible ice. The single-needle thermal pulse method can only measure the thermal conductivity of the substance, and cannot simultaneously obtain the specific heat and thermal diffusivity of the substance to be measured. The double-needle heat pulse method can simultaneously measure thermal conductivity, thermal diffusivity and specific heat. Therefore, in the current actual measurement and application, more double-needle heat pulse methods are used. [0003] The measurement...

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Problems solved by technology

But this method contains many assumptions, so it has many limitations in practical application

First, their study was limited to the temperature probe being bent, assuming that the heating probe does not change, these assumptions are not consistent with reality

In addition, another defect of this method is the most important one: their theoretical basis is based on the assumption that the bending deformation of the temperature probe is linear

Approximating a curve with a straight line will lead to large errors in most cases, especially when the curve has a large arc

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