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Heat conductivity measuring device and method

A technology of thermal conductivity and measuring device, which is applied in the field of thermophysical property measurement, can solve problems such as not fundamentally eliminating system errors, and achieve the effect of improving accuracy

Inactive Publication Date: 2010-07-14
UNIV OF SCI & TECH OF CHINA
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0005] Although many researchers have conducted in-depth research on the measurement of thermal conductivity by the thermal probe method, these studies are based on ignoring the heat capacity and diameter of the probe itself, and the contact thermal resistance is often ignored when measuring the thermal conductivity. Therefore, it does not fundamentally eliminate the systematic error of measurement

Method used

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  • Heat conductivity measuring device and method
  • Heat conductivity measuring device and method

Examples

Experimental program
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Effect test

Embodiment 1

[0051] Step 1. First, determine an assumed "specific heat capacity c p "And "contact thermal resistance R". Here specific heat capacity c p The value range of , for example, is between 0 and 5, and the contact thermal resistance R for liquids can be between -0.05 and 0.05, the contact thermal resistance R for solids, such as sand, can be between 0 and 0.6, and the soil can be It takes a value between 0 and 3. . Here, for different samples to be tested, the value range of the specific heat capacity and / or contact thermal resistance can be appropriately set by those skilled in the art, and the present invention is not limited to the above specific examples.

[0052] In addition, a certain number of random numbers subject to uniform distribution are generated, which are respectively used as the values ​​of "thermal conductivity λ". Here, various suitable algorithms such as the multiplication congruence method and the mixed congruence method can be used to generate random value...

Embodiment 2

[0062] Step 1. First, determine a hypothetical "contact thermal resistance R". Here, the value range of the contact thermal resistance R can be properly set in the manner described in the above-mentioned embodiment 1. And, use the multiplication and congruence method to generate a certain number of random numbers that obey the uniform distribution, which are respectively used as "thermal conductivity λ" and "specific heat capacity c p " value.

[0063] Then, after combining the two according to the Latin hypercube sampling method, they are substituted into the exact solution of the heat conduction differential equation represented by formula (1), and a set of most suitable "λ" and "c p " value, so that the average temperature difference between the numerical simulation curve obtained at this time and the experimental curve at each time point is the smallest, and this group of "λ" and "c p ” value as the equivalent thermal conductivity and equivalent specific heat capacity in ...

Embodiment 3

[0066] Step 1. First, use the multiplication and congruence method to generate a certain number of random numbers subject to uniform distribution, which are respectively used as "thermal conductivity λ" and "specific heat capacity c p " and "Contact thermal resistance R" values, these three sets of random values ​​are combined according to a certain combination method, such as the Latin hypercube sampling method, and then substituted into the exact solution of the thermal probe heat conduction differential equation represented by formula (1), from which Select a set of most suitable "λ", "c p " and "R" value, so that the average temperature difference between the numerical simulation curve obtained at this time and the experimental curve at each time point is the smallest, and the set of "λ", "c p " and "R" value as the equivalent value in the first calculation.

[0067] Step 2, similar to the above-mentioned embodiments 1 and 2, search systematically in an organized manner a...

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Abstract

The invention discloses thermal conductivity measuring device and method. The heat conductivity measuring device comprises a thermal probe, a thermoelectric couple, a collector and a data processor, wherein the thermal probe is inserted into a sample to be measured for thermal conductivity measurement; the thermoelectric couple is used for measuring the wall surface temperature of the thermal probe; the collector is used for collecting the wall surface temperature measured by the thermoelectric couple and corresponding measuring time; and the data processor is used for combining a thermal conduction differential equation expressing wall surface temperature increase with the thermal conductivity of the sample to be measured, which is obtained by inversely processing the wall surface temperature and the corresponding measuring time. The invention sufficiently considers the thermal probe capacity, the thermal contact resistance between the thermal probe and the sample to be measured, and the like, thereby greatly enhancing the measurement accuracy of parameters, i.e. thermal conductivity and the like.

Description

technical field [0001] The invention relates to the technical field of thermophysical property measurement, in particular to a thermal conductivity measurement device and method. Background technique [0002] The thermal conductivity characterizes the thermal conductivity of the material. It is an important physical parameter of the object and is related to the application of the material in various fields. For example, the thermal conductivity of the refrigerant is an indispensable parameter basis for the design of the refrigeration system. Theoretical research is an important aspect of research on ground source heat pump technology, underground cable heat dissipation, and temperature field of buried thermal oil pipelines. [0003] There are many methods for measuring thermal conductivity. At present, the thermal probe method is widely used in thermal conductivity measurement. The device used to measure thermal conductivity by the thermal probe method can be listed in Chine...

Claims

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Application Information

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IPC IPC(8): G01N25/20
Inventor 程文龙马然刘娜谢鲲
Owner UNIV OF SCI & TECH OF CHINA
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