The Research Of Microclimate State Under Clothing And The Measurement Of Moisture Resistance For Fabric | Posted on:2015-01-16 | Degree:Master | Type:Thesis | Country:China | Candidate:W W Zhu | Full Text:PDF | GTID:2251330428456365 | Subject:Textile engineering | Abstract/Summary: | PDF Full Text Request | The common methods of measuring water vapor permeability are the cup of water vapor permeability.sweating flat tester, instrument of dynamic moisture of water vapor permeability.The three methods evaluate moisture indicator according to the standard established by home and broad,which emphasis the ability of moisture transfer in themselves.Fabric microclimate apparatus research the ability of water vapor permeability through simulating actual situation of dressing.Current microclimate apparatus can be divided into the method of cup and the method of hot plate.But it exists some problems about the accuracy of water vapor permeability and the precision of the instrument.The new microclimate apparatus in this paper is based on the principle of "Walter" sweating and an passive device.which can accurately read the amount of water vapor permeability by one step.The temperature and humidity sensor between simulation skin and sample makes it easier to calculate the moisture resistance.When researchers used the new microclimate apparatus to do experiment of water vapor permeability.lt appeared some phenomenon that the relative humidity under clothing was generally beyond100%.When researchers calculate the moisture resistance in100%of relative humidity on the basis of scholars’ practice.Strangely she found no significant difference of moisture resistance among different fabrics. Finally she got objective results by factual moisture humidity.Whether it will appear the phenomenon of supersaturation or notThis paper make some experiments and theoretical research according to this question.Finally some conclusions are founded.(1)The condensing of atmospheric water vapor need to be saturated.Another prerequisite is the existence of condensation nuclei.In extremely pure atmosphere water vapor will not condensation though it is saturated.When the droplet radius is different the corresponding saturated vapor pressure and the degree of supersaturation are also different. Range of water vapor pressure is0.00689bar-0.1353bar when the radius of the droplet is100xl0-10m and range of the temperature is0℃-50℃.And the standard atmospheric pressure is101.325kpa, the range of supersaturation1.128-1.097at this time.Droplet radius in the atmosphere range from1xl0-6m to1Ox1O-6m.After the balance for2.5hours radius of water vapor molecules in the microclimate instrument close to or smaller than the droplet.So the water vapor is supersaturated at a room temperature and the relative humidity range close to100%-112.8%. The results of two experiments and the impermeable plastic film further validate this inference.(2)With the increasing of thickness of fabric the amount of water vapor permeability decreases for cotton and synthetic fabrics.We can see that the thickness of fabrics have an great effect on water vapor permeability.The amount of water vapor permeability of two and half layers Gore-tex fabric is significantly higher than the three layers Gore-tex fabrics.The amount of water vapor permeability of Gore-tex fabrics is worse than ordinary fabrics.But they are far better than airtight plastic film.While the difference is not apparent for hemp fabric,which has a closed relationship with the high moisture permeability in themselves.(3)The relationship between moisture resistance and water vapor permeability of the fabric basically showed the opposite trend.When the amount of water vapor permeability is larger moisture resistance is smaller conversely.Inner surface temperature and relative humidity of the Gore-tex fabrics are usually high so that the moisture resistance is high on average.Compared with ordinary dressing fabric wet comfort is poor. | Keywords/Search Tags: | New microclimate apparatus, Supersaturated water vapor, Relative humidity, Water vapor permeability, Moisture resistance | PDF Full Text Request | Related items |
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