A device for testing the hydrothermal change characteristics of aqueous porous media during freezing and thawing

Abstract

The invention relates to a device for testing the hydrothermal change characteristics of porous media containing water during the freezing and thawing process. Thermal insulation function, the cooling coil installed on the inner wall and bottom of the outer model box is connected with two external cold baths to control temperature and overall temperature rise and fall. The interlayer space of the inner and outer model boxes can be filled with alcohol, kerosene, ethylene glycol, etc. The freezing point liquid is used as the filling liquid to improve the temperature control accuracy and constant temperature effect. The invention is mainly used to test the hydrothermal characteristic parameters of the porous medium in the freeze-thaw cycle process, including temperature, volume unfrozen water content, matrix suction, etc., and then draw the moisture characteristic curve of the porous medium in the freeze-thaw process. The invention has the characteristics of simple operation, stable work, high temperature control precision, and fast overall heating and cooling speed, and the data acquisition instrument automatically collects data, thereby realizing the effective testing and monitoring of hydrothermal characteristic parameters in the process of freezing and thawing porous media. Accurate acquisition of moisture characteristic curve.

Description

technical field [0001] The invention relates to an experimental test device, in particular to a device for testing the hydrothermal change characteristics of a water-containing porous medium during the freeze-thaw process. The device can realize the overall temperature control and rapid freezing and thawing of the sample, and can effectively measure the hydrothermal characteristic elements of the sample during the freezing and thawing process, such as the change test of temperature, volume unfrozen water content and matrix suction, etc. An effective device for studying the freeze-thaw hydrothermal change characteristics and the freeze-thaw moisture characteristic curve of porous media containing water. Background technique [0002] The freeze-thaw test has a very wide application background in the fields of material frost resistance testing, frost heave prediction of engineering structure foundations in permafrost regions, new drug packaging and transportation, etc. Conside...

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Problems solved by technology

Generally speaking, the similarity between the freeze-thaw cycle and the dry-wet cycle has been verified by experiments and there is no doubt, but the difference between the two is also obvious. The freezing and thawing of aqueous porous media not only involves the phase change of water. , and is often accompanied by the migration of water and solute, the redistribution and unevenness of water in this way will lead to great differences in the suction force of the matrix at different positions, which does not exist in moisture absorption and dehydration, and of course there are dry and wet The mechanism of the hysteresis effect in the cycle process is quite different from the hysteresis effect mechanism in the freeze-thaw process. For example, in addition to the "ink bottle" effect during the freeze-thaw process, the supercooling of water will also cause inconsistencies in the freezing and melting curves.

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