Hagen-Poiseuille Modification Formula For The Fabric Permeability Study Based On Fractal Theory

With the development of the living standard, people have higher hopes for the comfortable performance of fabric. The air permeability, as one of the important indicators of comfortable performance, is particularly important. Fabric's air permeability impacts not only the comfortable performance of fabric, but also the healthy performance. In people's daily life, the body will continue to sweat (including significant and non-significant sweat), and sweat emits and diffuses to the outside through the fabrics, so the fabric air permeability will have a direct impact on human comfort. Fabric must have a certain degree of permeability for timely replacement of the air inside the clothes to keep people comfortable and clean.The subject makes a research mainly into the air permeability of fabric and chooses the plain cotton fabric as the study object, trying to find out how the fabric air permeability is effcted by its structure factors. First, the cotton fabric has been very popular for thousands of years with its characteristic softness, moisture absorption, excellent durability properties. As such an enduring, attention devoted textiles, the importance of the study of its air permeability performance goes without saying. Second, considering the research methods are still at an immature stage, the most commonly and simplest plain weave fabric can make the experiment more reliable and stable, and also keep a easy workability.The subject chooses plain cotton fabric of different specifications as the research object. According to Hagen-Poiseuille Law and the related fractal theory, we can analysis quantitatively of the relationship between cotton fabric pores size, thickness and its air permeability based on the experiments data, trying to provide a train of thought to the air permeability research of fabric.First, the chosen plain cotton fabrics's basic specifications and performance are measured using conventional methods, the experimental data is the basis of discussions. Second the Hagen-Poiseuille law's logical or mathematical process and its shortcomings is analyzed and appropriate adjustments are needed to get the relation between fabric air permeability and structural factors which includes parameters to be determined by related fractal methods. Experimental data processing results show that fabric thickness and air permeability have a high correlation, the smaller thickness of similiar fabrics, the better air permeabilityperformance, we get relation (?); the fabric pore size and the fabric air permeability have also a high relevance : bigger pore size of similar fabrics mean the greater permeability of the fabric, we get the relation (?) through the fabric images, while (?) by the experiment data,the error rate is about 13%.