A Method for Obtaining Effective Capillary Radius of Unidirectional Fiber Bundle

Abstract

The invention relates to a method for obtaining an effective capillary radius of a unidirectional fiber bundle. The method is technically characterized in that the unidirectional fiber bundle is bundled inside a circular tube and suspended on a balance by using a capillary action principle; subsequently the fiber bundle is contacted with liquid, such as water, mineral oil or resin, and a change of liquid rising quality along with time is recorded; and finally an experiment result is fitted by using least squares so as to obtain an optimal value of the capillary radius. According to the method, the capillary radius is obtained by reversing an actual flowing result and is direct embodiment of wettability of the unidirectional fiber bundle; a measurement operation on aperture distribution of the fiber bundle is saved; the method is simple and convenient to operate; and meanwhile, an influence of a liquid surface tension to the fiber bundle is eliminated; and a result is accurate and reliable.

Description

technical field [0001] The invention belongs to the field of composite materials, and in particular relates to a method for obtaining the effective capillary radius of a unidirectional fiber bundle. Background technique [0002] The distribution of pores inside the fiber bundle greatly affects the wetting process of the liquid inside. However, due to the complexity of the internal pores (different sizes and uneven distribution), the concept of equivalent capillary pore diameter is used to describe the internal pores, that is, the complex pores in the fiber bundle are equivalent to a capillary with the same flow characteristics. At present, complex experimental methods (mercury injection method, bubble pressure method, etc.) are used at home and abroad to first obtain the pore size distribution of the fiber bundle, and then average the pore size to obtain the equivalent capillary radius, but it is difficult to directly reflect the fiber bundle. The flow characteristics cause...

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Problems solved by technology

At present, complex experimental methods (mercury porosimetry, bubble pressure method, etc.) are used at home and abroad to first obtain the pore size distribution of the fiber bundle, and then average the pore size to obtain the equivalent capillary radius, but it is difficult to directly reflect the fiber bundle. The flow characteristics of the flow characteristics, resulting in a large deviation between the flow theoretical calculation value and the experimental value, affect the follow-up analysis of the wetting behavior of fiber bundles

People such as Benjamin J.Mullins obtained the effective capillary radius of this kind of porous fabric by testing the fluid's rising weight change in the high-porosity filter medium, (Capillarity in fibrous filter media: Relationship to filter properties.Chemical Engineering Science 62(2007 ) 6191-6198), did not study the unidirectional fiber bundles, and did not eliminate the influence of liquid-solid surface tension when measuring the rising quality of the liquid; Qi Hongjin and others invented a quality classification method to measure the pore size distribution of the yarn ( Measuring device and method for yarn capillary pore size distribution based on quality classification, 201010513290.1), it is also necessary to average the pore size distribution to obtain the effective capillary radius of the yarn, but can the average process reflect the The infiltration process itself must be carefully

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