Thermal Absorptivity and Other Thermal Comfort Parameters of Rib Knitted Fabrics
Title Alternative:Tepelná jímavost a ostatní parametry tepelného komfortu žebrových úpletů
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Abstract
Cílem teto práce je zjistit vliv různých profilů funkčních žebrových pletenin na jejich tepelné vlastnosti jako je tepelná vodivost, tepelná absorpce a tepelný odpor. Práce zahrnuje představení nového modelu pro extrapolaci tepelné absorpce vzhledem k rozdílu v oblasti interakce mezi lidskou kůži a žebrovou pleteninou. Tepelná absorpce je indikátorem pocitu tepla a chladu. Vzorky byly vyrobeny z polyesterové příze. Studie potvrzuje, že změna profilu povrchu žebrové pleteniny má podstatný vliv na její tepelné vlastnosti. Na základě této skutečnosti byl poprvé uveden nový termín tepelná kontaktní absorpce. Tepelná kontaktní absorpce představuje modifikaci tepelné absorpce vzhledem ke kontaktním bodům mezi dvěma povrchy. Stejně tak nově vyvinutý model je v souladu s naměřenými hodnotami.V další časti práce je ověřeno, see oblast s vyšší interakci mezi lidskou kůži a žebrovou pleteninou zvyšuje hodnoty tepelné absorpce. To je převážně způsobeno nárůstem kontaktních míst, která poskytuji větší plochu pro přenos tepla kondukci. Stejně důležité bylo také změřit hodnoty tepelného odporu a tepelné vodivosti. Byla zjištěna korelace mezi tepelným odporem, tepelnou vodivosti a kontaktní plochou. Bylo zjištěno, see existuje významná ekvivalence mezi tepelnými parametry a profilem povrchu.Třicet respondentů dále provedlo subjektivní analýzu pro potvrzeni hodnot z objektivního měřeni. Rovněž byl změřen vliv paralelního a svislého směru na propustnost vodních par. Bylo zjištěno, že směr má významný vliv na propustnost vzduchu a vody. Studie dospěla k závěru, že funkční žebrové pleteniny vyrobené z polyesteru mají u různého profilu povrchu různou tepelnou absorpci. Více kontaktních bodů mezi lidskou kůži a žebrovou pleteninou způsobuje chladivý účinek. To vše bylo studováno na funkčních žebrových pleteninách, které byly vyrobeny na plochém pletacím stroji.
The objective of this study is to investigate the impact of changing the profile of functional knitted ribs on thermal properties of fabric, including thermal conductivity, thermal absorptivity, and thermal resistance. This introduced a new model for the extrapolation of thermal absorptivity due to the variation in the interaction area between human skin and knitted rib fabric. Thermal absorptivity is an indicator of the warm-cool feeling. Polyester yarn was used to produce study samples. The study endorsed that variation in surface profile impacts the thermal parameters.Based on this discussion a new term thermal contact absorptivity was created and introduced for the first time. Thermal contact absorptivity indicates the modification in thermal absorptivity due to the contact points between two surfaces. The model was developed using a novel approach and had extensive agreement with measured values. It was further verified that with a higher interaction area between human skin and knitted rib the thermal absorptivity values escalated. This was predominantly due to the increase in contact points, which provided more area for heat transfer through conduction. The equally important thermal resistance and thermal conductivity values were measured, and a correlation was developed between thermal resistance, thermal conductivity, and contact area. A significant equivalence was found between the thermal parameters and surface profile. Subjective analysis was also conducted by involving a group of 30 people for the confirmation of objective values. Impact of parallel and vertical direction on water vapour permeability was measured and a significant impact from direction of air and water permeability was found. In conclusion, the knitted rib made using polyester with a discriminated surface profile provides a different thermal absorptivity. Higher contact points between human skin and knitted rib fabric give a cooling effect which was investigated on functional ribs produced on a flat knitting machine.
The objective of this study is to investigate the impact of changing the profile of functional knitted ribs on thermal properties of fabric, including thermal conductivity, thermal absorptivity, and thermal resistance. This introduced a new model for the extrapolation of thermal absorptivity due to the variation in the interaction area between human skin and knitted rib fabric. Thermal absorptivity is an indicator of the warm-cool feeling. Polyester yarn was used to produce study samples. The study endorsed that variation in surface profile impacts the thermal parameters.Based on this discussion a new term thermal contact absorptivity was created and introduced for the first time. Thermal contact absorptivity indicates the modification in thermal absorptivity due to the contact points between two surfaces. The model was developed using a novel approach and had extensive agreement with measured values. It was further verified that with a higher interaction area between human skin and knitted rib the thermal absorptivity values escalated. This was predominantly due to the increase in contact points, which provided more area for heat transfer through conduction. The equally important thermal resistance and thermal conductivity values were measured, and a correlation was developed between thermal resistance, thermal conductivity, and contact area. A significant equivalence was found between the thermal parameters and surface profile. Subjective analysis was also conducted by involving a group of 30 people for the confirmation of objective values. Impact of parallel and vertical direction on water vapour permeability was measured and a significant impact from direction of air and water permeability was found. In conclusion, the knitted rib made using polyester with a discriminated surface profile provides a different thermal absorptivity. Higher contact points between human skin and knitted rib fabric give a cooling effect which was investigated on functional ribs produced on a flat knitting machine.
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Subject(s)
funkční žebrové pleteniny, tepelná vodivost, tepelná absorpce, tepelný odpor, kontaktní body, Functional knitted ribs, Thermal conductivity, Thermal absorptivity, Thermal resistance, contact points