The Experts below are selected from a list of 1695 Experts worldwide ranked by ideXlab platform
Faming Wang - One of the best experts on this subject based on the ideXlab platform.
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effects of fabric thickness and material on apparent wet conductive thermal Resistance of knitted fabric skin on sweating manikins
Journal of Thermal Biology, 2017Co-Authors: Faming Wang, Danda Lai, We ShiAbstract:Abstract Currently, no published standard and research work have addressed the basic requirements on knitted fabric ‘skin’ on sweating manikins. In this study, we performed 252 experiments to investigate the influence of fabric thickness and material on the apparent ‘wet’ conductive (or effective) thermal Resistance of the fabric ‘skin’ using a ‘Newton’ manikin. Four types of cotton fabric ‘skin’ (fabric thickness: 0.38, 0.54, 0.92 and 1.43 mm) and three types of polyester fabric ‘skin’ (fabric thickness: 0.41, 0.54 and 1.0 mm) were selected and their ‘wet’ conductive thermal Resistance was determined. Empirical equations were also developed for each fabric ‘skin’ to predict wet fabric ‘skin’ surface temperatures. It was found that both fabric thickness and material significantly affected the apparent ‘wet’ conductive thermal Resistance. Clothing total Evaporative Resistance determined using thin fabric ‘skin’ (e.g., CO1, CO2) was normally lower than that determined using thick fabric ‘skin’ (e.g., CO4). Besides, synthetic fabric ‘skin’ tended to have a larger apparent ‘wet’ conductive thermal Resistance than the cotton fabric ‘skin’ due to a smaller amount of moisture contained. Hence, there is a great need to standardize the fabric ‘skin’ to eliminate the influence of fabric ‘skin’ on the measurement of clothing Evaporative Resistance by means of a sweating manikin.
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measurements of clothing Evaporative Resistance using a sweating thermal manikin an overview
Industrial Health, 2017Co-Authors: Faming WangAbstract:: Evaporative Resistance has been widely used to describe the Evaporative heat transfer property of clothing. It is also a critical variable in heat stress models for predicting human physiological responses in various environmental conditions. At present, sweating thermal manikins provide a fast and cost-effective way to determine clothing Evaporative Resistance. Unfortunately, the measurement repeatability and reproducibility of Evaporative Resistance are rather low due to the complicated moisture transfer processes through clothing. This review article presents a systematical overview on major influential factors affecting the measurement precision of clothing Evaporative Resistance measurements. It also illustrates the state-of-the-art knowledge on the development of test protocol to measure clothing Evaporative Resistance by means of a sweating manikin. Some feasible and robust test procedures for measurement of clothing Evaporative Resistance using a sweating manikin are described. Recommendations on how to improve the measurement accuracy of clothing Evaporative Resistance are addressed and expected future trends on development of advanced sweating thermal manikins are finally presented.
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measurements of clothing Evaporative Resistance using a sweating thermal manikin an overview
Industrial Health, 2017Co-Authors: Faming WangAbstract:: Evaporative Resistance has been widely used to describe the Evaporative heat transfer property of clothing. It is also a critical variable in heat stress models for predicting human physiological responses in various environmental conditions. At present, sweating thermal manikins provide a fast and cost-effective way to determine clothing Evaporative Resistance. Unfortunately, the measurement repeatability and reproducibility of Evaporative Resistance are rather low due to the complicated moisture transfer processes through clothing. This review article presents a systematical overview on major influential factors affecting the measurement precision of clothing Evaporative Resistance measurements. It also illustrates the state-of-the-art knowledge on the development of test protocol to measure clothing Evaporative Resistance by means of a sweating manikin. Some feasible and robust test procedures for measurement of clothing Evaporative Resistance using a sweating manikin are described. Recommendations on how to improve the measurement accuracy of clothing Evaporative Resistance are addressed and expected future trends on development of advanced sweating thermal manikins are finally presented.
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The relationship between air layers and Evaporative Resistance of male Chinese ethnic clothing
Applied Ergonomics, 2016Co-Authors: Faming Wang, Hui PengAbstract:Abstract In this study, the air layer distribution and Evaporative Resistances of 39 sets of male Chinese ethnic clothing were investigated using a sweating thermal manikin and the three-dimensional (3D) body scanning technique. Relationships between the Evaporative Resistance and air layers (i.e., air gap thickness and air volume) were explored. The results demonstrated that the clothing total Evaporative Resistance increases with the increasing air gap size/air volume, but the rate of increase gradually decreases as the mean air gap size or the total air volume becomes larger. The clothing total Evaporative Resistance reaches its maximum when the average air gap size and the total air volume are 41.6 mm and 69.9 dm 3 , respectively. Similar general trends were also found between local mean air gap size and clothing local Evaporative Resistance at different body parts. However, different body parts show varied rates of increase and decrease in the local Evaporative Resistance. The research findings provide a comprehensive database for predicting overall and local human thermal comfort while wearing male Chinese ethnic clothing.
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Development of Empirical Equations to Predict Sweating Skin Surface Temperature for Thermal Manikins in Warm Environments.
2016Co-Authors: Faming Wang, Kalev Kuklane, Ingvar HolmérAbstract:Clothing Evaporative Resistance is one of the most important parameters for clothing comfort. The clothing evaporation Resistance can be measured on a sweating guarded hotplate, a sweating thermal manikin or a human subject. The sweating thermal manikin gives the most accurate value on Evaporative Resistance of the whole garment ensemble compared to the other two methods. The determination of clothing Evaporative Resistance on a thermal manikin requires sweating simulation. This can be achieved by either a pre-wetted fabric skin on top of the manikin (TORE), or a waterproof but permeable Gore-tex skin filled with water inside. The addition of a fabric skin can introduce a temperature difference between the manikin surface and the sweating skin surface. However, calculations on clothing Evaporative Resistance have often been based on the thermal manikin surface temperature. A previous study showed that the temperature differences can cause an error up to 35.9 % on the clothing Evaporative Resistance. In order to reduce such an error, an empirical equation to predict the skin surface temperature might be helpful. In this study, a cotton knit fabric skin and a Gore-tex skin were used to simulate two types of sweating. The cotton fabric skin was rinsed with tap water and centrifuged in a washing machine for 4 seconds to ensure no water drip. A Gore-tex skin was put on top of the pre-wetted cotton skin on a dry heated thermal manikin ‘Tore’ in order to simulate senseless sweating, similar to thermal manikins ‘Coppelius’ and ‘Walter’. Another simulation involved the pre-wetted fabric skin covered on top of the Gore-tex skin in order to simulate sensible sweating. This type of sweating simulation can be widely found on many thermal manikins worldwide, e.g. ‘Newton’. Six temperature sensors (Sensirion Inc, Switzerland) were attached on six sites of the skin outer surface by white thread rings to record the skin surface temperature. Twelve skin tests for each skin combination were performed at three different ambient temperatures: 34, 25 and 20 oC. Two empirical equations to predict the skin surface temperature were developed based on the mean manikin surface temperature, mean fabric skin surface temperature and the total heat loss. The prediction equations for the senseless sweating and sensible sweating on the thermal manikin ‘Tore’ were Tsk=34.0-0.0146HL and Tsk=34.0-0.0190HL, respectively. Further study should validate these two empirical equations, however. (Less)
Ingvar Holmér - One of the best experts on this subject based on the ideXlab platform.
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Development of Empirical Equations to Predict Sweating Skin Surface Temperature for Thermal Manikins in Warm Environments.
2016Co-Authors: Faming Wang, Kalev Kuklane, Ingvar HolmérAbstract:Clothing Evaporative Resistance is one of the most important parameters for clothing comfort. The clothing evaporation Resistance can be measured on a sweating guarded hotplate, a sweating thermal manikin or a human subject. The sweating thermal manikin gives the most accurate value on Evaporative Resistance of the whole garment ensemble compared to the other two methods. The determination of clothing Evaporative Resistance on a thermal manikin requires sweating simulation. This can be achieved by either a pre-wetted fabric skin on top of the manikin (TORE), or a waterproof but permeable Gore-tex skin filled with water inside. The addition of a fabric skin can introduce a temperature difference between the manikin surface and the sweating skin surface. However, calculations on clothing Evaporative Resistance have often been based on the thermal manikin surface temperature. A previous study showed that the temperature differences can cause an error up to 35.9 % on the clothing Evaporative Resistance. In order to reduce such an error, an empirical equation to predict the skin surface temperature might be helpful. In this study, a cotton knit fabric skin and a Gore-tex skin were used to simulate two types of sweating. The cotton fabric skin was rinsed with tap water and centrifuged in a washing machine for 4 seconds to ensure no water drip. A Gore-tex skin was put on top of the pre-wetted cotton skin on a dry heated thermal manikin ‘Tore’ in order to simulate senseless sweating, similar to thermal manikins ‘Coppelius’ and ‘Walter’. Another simulation involved the pre-wetted fabric skin covered on top of the Gore-tex skin in order to simulate sensible sweating. This type of sweating simulation can be widely found on many thermal manikins worldwide, e.g. ‘Newton’. Six temperature sensors (Sensirion Inc, Switzerland) were attached on six sites of the skin outer surface by white thread rings to record the skin surface temperature. Twelve skin tests for each skin combination were performed at three different ambient temperatures: 34, 25 and 20 oC. Two empirical equations to predict the skin surface temperature were developed based on the mean manikin surface temperature, mean fabric skin surface temperature and the total heat loss. The prediction equations for the senseless sweating and sensible sweating on the thermal manikin ‘Tore’ were Tsk=34.0-0.0146HL and Tsk=34.0-0.0190HL, respectively. Further study should validate these two empirical equations, however. (Less)
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A Study on Local Cooling of Garments with Ventilation Fans and Openings Placed at Different Torso Sites
International Journal of Industrial Ergonomics, 2013Co-Authors: Mengmeng Zhao, Ingvar Holmér, Kalev Kuklane, Faming Wang, Jun LiAbstract:Abstract in Undetermined The aim of the study was to examine the various design features of ventilated garments on cooling performance. Five jackets with small ventilation units and closable openings were designed. The ventilation units with a flow rate of 12 l/s were placed at five different torso sites. They were examined on a sweating thermal manikin in four clothing opening conditions in a warm environment (Ta=Tmanikin=34 °C, RH=60 %, Va=0.4 m/s). Total torso cooling was increased by 137 to 251 %, and clothing total dynamic Evaporative Resistance was decreased by 43 to 69 %. Neither the ventilation location nor the opening design had a significant difference on total torso cooling. The ventilation location had a significant difference on localized intra-torso cooling, but not the opening design. When the ventilation units were placed at the local zone where it was ventilated, that zone underwent the highest cooling than other local zones. The study indicated that the ventilation units should be placed at the region where it required the most Evaporative cooling, e.g. along the spine area and the lower back. The openings could be adjusted (closed or opened) to make comfortable air pressure for the wearers but without making significant difference on the whole torso cooling under this flow rate. (Less)
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Localised boundary air layer and clothing Evaporative Resistances for individual body segments
Ergonomics, 2012Co-Authors: Faming Wang, T.s. Mayor, Kalev Kuklane, Miguel Ribeiro, Vincenzo Molinaro, Simona Del Ferraro, Ingvar HolmérAbstract:Evaporative Resistance is an important parameter to characterise clothing thermal comfort. However, previous work has focused mainly on either total static or dynamic Evaporative Resistance. There is a lack of investigation of localised clothing Evaporative Resistance. The objective of this study was to study localised Evaporative Resistance using sweating thermal manikins. The individual and interaction effects of air and body movements on localised resultant Evaporative Resistance were examined in a strict protocol. The boundary air layer's localised Evaporative Resistance was investigated on nude sweating manikins at three different air velocity levels (0.18, 0.48 and 0.78 m/s) and three different walking speeds (0, 0.96 and 1.17 m/s). Similarly, localised clothing Evaporative Resistance was measured on sweating manikins at three different air velocities (0.13, 0.48 and 0.70 m/s) and three walking speeds (0, 0.96 and 1.17 m/s). Results showed that the wind speed has distinct effects on local body segme...
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Effect of temperature difference between manikin and wet fabric skin surfaces on clothing Evaporative Resistance: how much error is there?
International Journal of Biometeorology, 2012Co-Authors: Faming Wang, Kalev Kuklane, Ingvar HolmérAbstract:Clothing Evaporative Resistance is one of the inherent factors that impede heat exchange by sweating evaporation. It is widely used as a basic input in physiological heat strain models. Previous studies showed a large variability in clothing Evaporative Resistance both at intra-laboratory and inter-laboratory testing. The errors in Evaporative Resistance may cause severe problems in the determination of heat stress level of the wearers. In this paper, the effect of temperature difference between the manikin nude surface and wet textile skin surface on clothing Evaporative Resistance was investigated by both theoretical analysis and thermal manikin measurements. It was found that the temperature difference between the skin surface and the manikin nude surface could lead to an error of up to 35.9% in Evaporative Resistance of the boundary air layer. Similarly, this temperature difference could also introduce an error of up to 23.7% in the real clothing total Evaporative Resistance ( R _ et_real
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determination of clothing Evaporative Resistance on a sweating thermal manikin in an isothermal condition heat loss method or mass loss method
Annals of Occupational Hygiene, 2011Co-Authors: Faming Wang, Kalev Kuklane, Ingvar HolmérAbstract:This paper addresses selection between two calculation options, i.e heat loss option and mass loss option, for thermal manikin measurements on clothing Evaporative Resistance conducted in an isothermal condition (Tmanikin = Ta = Tr). Five vocational clothing ensembles with a thermal insulation range of 1.05–2.58 clo were selected and measured on a sweating thermal manikin ‘Tore’. The reasons why the isothermal heat loss method generates a higher Evaporative Resistance than that of the mass loss method were thoroughly investigated. In addition, an indirect approach was applied to determine the amount of Evaporative heat energy taken from the environment. It was found that clothing Evaporative Resistance values by the heat loss option were 11.2–37.1% greater than those based on the mass loss option. The percentage of Evaporative heat loss taken from the environment (He,env) for all test scenarios ranged from 10.9 to 23.8%. The real Evaporative cooling efficiency ranged from 0.762 to 0.891, respectively. Furthermore, it is evident that the Evaporative heat loss difference introduced by those two options was equal to the heat energy taken from the environment. In order to eliminate the combined effects of dry heat transfer, condensation, and heat pipe on clothing Evaporative Resistance, it is suggested that manikin measurements on the determination of clothing Evaporative Resistance should be performed in an isothermal condition. Moreover, the mass loss method should be applied to calculate clothing Evaporative Resistance. The isothermal heat loss method would appear to overestimate heat stress and thus should be corrected before use. (Less)
Kalev Kuklane - One of the best experts on this subject based on the ideXlab platform.
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Using a thermal manikin to determine Evaporative Resistance and thermal insulation – A comparison of methods:
Journal of Industrial Textiles, 2020Co-Authors: Róbert Toma, Kalev Kuklane, Miloš Fojtlín, Jan Fišer, Miroslav JichaAbstract:Heat transfer from the human body, especially through the evaporation of sweat from the skin, is often restricted when protective clothing is used, which may result in overheating. For this reason,...
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using a thermal manikin to determine Evaporative Resistance and thermal insulation a comparison of methods
Journal of Industrial Textiles, 2020Co-Authors: Róbert Toma, Kalev Kuklane, Miloš Fojtlín, Jan Fišer, Miroslav JichaAbstract:Heat transfer from the human body, especially through the evaporation of sweat from the skin, is often restricted when protective clothing is used, which may result in overheating. For this reason,...
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Development of Empirical Equations to Predict Sweating Skin Surface Temperature for Thermal Manikins in Warm Environments.
2016Co-Authors: Faming Wang, Kalev Kuklane, Ingvar HolmérAbstract:Clothing Evaporative Resistance is one of the most important parameters for clothing comfort. The clothing evaporation Resistance can be measured on a sweating guarded hotplate, a sweating thermal manikin or a human subject. The sweating thermal manikin gives the most accurate value on Evaporative Resistance of the whole garment ensemble compared to the other two methods. The determination of clothing Evaporative Resistance on a thermal manikin requires sweating simulation. This can be achieved by either a pre-wetted fabric skin on top of the manikin (TORE), or a waterproof but permeable Gore-tex skin filled with water inside. The addition of a fabric skin can introduce a temperature difference between the manikin surface and the sweating skin surface. However, calculations on clothing Evaporative Resistance have often been based on the thermal manikin surface temperature. A previous study showed that the temperature differences can cause an error up to 35.9 % on the clothing Evaporative Resistance. In order to reduce such an error, an empirical equation to predict the skin surface temperature might be helpful. In this study, a cotton knit fabric skin and a Gore-tex skin were used to simulate two types of sweating. The cotton fabric skin was rinsed with tap water and centrifuged in a washing machine for 4 seconds to ensure no water drip. A Gore-tex skin was put on top of the pre-wetted cotton skin on a dry heated thermal manikin ‘Tore’ in order to simulate senseless sweating, similar to thermal manikins ‘Coppelius’ and ‘Walter’. Another simulation involved the pre-wetted fabric skin covered on top of the Gore-tex skin in order to simulate sensible sweating. This type of sweating simulation can be widely found on many thermal manikins worldwide, e.g. ‘Newton’. Six temperature sensors (Sensirion Inc, Switzerland) were attached on six sites of the skin outer surface by white thread rings to record the skin surface temperature. Twelve skin tests for each skin combination were performed at three different ambient temperatures: 34, 25 and 20 oC. Two empirical equations to predict the skin surface temperature were developed based on the mean manikin surface temperature, mean fabric skin surface temperature and the total heat loss. The prediction equations for the senseless sweating and sensible sweating on the thermal manikin ‘Tore’ were Tsk=34.0-0.0146HL and Tsk=34.0-0.0190HL, respectively. Further study should validate these two empirical equations, however. (Less)
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Evaporative Resistance of newly designed bicycle helmets
Extreme physiology and medicine, 2015Co-Authors: Kalev Kuklane, Helena Aljaste, Sixten Sebastian HeidmetsAbstract:As a continuation of the work on the ventilation requirements for a bicycle helmet for commuters [1], 15 full scale helmet mock-ups were created and tested for dry heat loss properties [2] in a wind tunnel on a thermal head manikin [3]. This paper presents the results of the wet heat transfer measurements in the form of Evaporative Resistance.
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CLOTHING REAL Evaporative Resistance DETERMINED BY MEANS OF A SWEATING THERMAL MANIKIN: A NEW ROUND-ROBIN STUDY
2014Co-Authors: Faming Wang, T.s. Mayor, Jean Leonard, Magdalena Zwolińska, Chris Wong, Kalev Kuklane, George Havenith, Simon Hodder, J KishinoAbstract:The previous round-robin (RR) study on clothing Evaporative Resistance (Ret) has shown that the repeatability and reproducibility of clothing Ret measurements on sweating manikins were rather low. To further examine and enhance the measurement accuracy, a new strict but feasible test protocol was proposed and thoroughly examined in a new round-robin test. Eight laboratories participated in this study and three types of sweating manikins were used. Six clothing ensembles including body mapping cycling wear, light summer workwear, typical spring and autumn clothing for people living in subtropical regions, cold protective clothing and functional Gore-Tex coverall were selected. The measurement repeatability and reproducibility are analysed. The ultimate goal of the RR study is to provide solid support for amending ASTM F2370 standard and/or drafting a new ISO/EN standard.
Chuansi Gao - One of the best experts on this subject based on the ideXlab platform.
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Effect of temperature difference between manikin and wet fabric skin surfaces on clothing Evaporative Resistance: how much error is there?
International journal of biometeorology, 2011Co-Authors: Faming Wang, Kalev Kuklane, Chuansi Gao, Ingvar HolmérAbstract:Clothing Evaporative Resistance is one of the inherent factors that impede heat exchange by sweating evaporation. It is widely used as a basic input in physiological heat strain models. Previous studies showed a large variability in clothing Evaporative Resistance both at intra-laboratory and inter-laboratory testing. The errors in Evaporative Resistance may cause severe problems in the determination of heat stress level of the wearers. In this paper, the effect of temperature difference between the manikin nude surface and wet textile skin surface on clothing Evaporative Resistance was investigated by both theoretical analysis and thermal manikin measurements. It was found that the temperature difference between the skin surface and the manikin nude surface could lead to an error of up to 35.9% in Evaporative Resistance of the boundary air layer. Similarly, this temperature difference could also introduce an error of up to 23.7% in the real clothing total Evaporative Resistance (Ret_real < 0.1287 kPa m2/W). Finally, it is evident that one major error in the calculation of Evaporative Resistance comes from the use of the manikin surface temperature instead of the wet textile fabric skin temperature.
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Localized Evaporative Resistance: Correction for body and air movement
2011Co-Authors: Faming Wang, Kalev Kuklane, Chuansi Gao, Li-yen Lin, Miguel Ribeiro, Simona Del Ferraro, Tiago Sotto Mayor, Vincenzo Molinaro, Ingvar HolmérAbstract:Clothing Evaporative Resistance determines how much sweat could be escaped through one’s clothing to the surrounding environment (Wang et al. 2011). Although ISO 9920 (ISO 992
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Development and Validation of an Empirical Equation to Predict Sweating Skin Surface Temperature for Thermal Manikins
2010Co-Authors: Faming Wang, Ingvar Holmér, Kalev Kuklane, Chuansi Gao, George HavenithAbstract:Thermal manikins are useful tools to study the clothing comfort and environmental ergonomics. The simulation of sweating can be achieved by putting a highly wicking stretchable knit fabric “skin” on top of the manikin. However, the addition of such a fabric skin makes it is difficult to accurately measure the skin surface temperature. Moreover, it takes considerable amount of time to measure the fabric skin surface temperature for each test. At present the attachment of temperature sensors to the wet fabric skin is still a challenge. The distance of the sensors to the fabric skin could significantly influence the temperature and relative humidity values of the wet skin surface. Hence, we conducted an intensive skin study on a dry thermal manikin to investigate the relationships among the nude manikin surface temperature, heat losses and the fabric skin surface temperature. An empirical equation was developed and validated on the thermal manikin "Tore" at Lund University. The empirical equation at ambient temperature 34 oC is Tsk =34.00- 0.0103HL. This equation can be used to enhance the prediction accuracy on the sweating skin surface temperature and the calculation of clothing Evaporative Resistance. (Less)
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A Study on Evaporative Resistances of Two Skins Designed for Thermal Manikin Tore under Different Environmental Conditions
Journal of Fiber Bioengineering and Informatics, 2008Co-Authors: Faming Wang, Kalev Kuklane, Chuansi Gao, Ingvar HolmérAbstract:A cotton skin and Gore-Tex skin were designed for thermal manikin "Tore" to simulate different sweating styles (wet cotton skin inside and Gore-Tex outside to simulate sweating style of thermal manikin "Walter", and Gore-Tex skin inside with wet cotton skin outside to simulate sweating style of thermal manikins "Newton". The Evaporative Resistances of two skin combinations with clothing ensembles were compared at two different environmental conditions. In addition, the total Evaporative Resistance of clothing ensemble was calculated by both heat loss method (option 1) and mass loss method (option 2) according to ASTM F 2370. We found that the effect of different sweating mechanisms on clothing Evaporative Resistance should be considered. The results showed that the total Evaporative Resistances obtained by option 2 were more accurate than values by option 1 under an isothermal condition. It was also found that total Evaporative Resistance differences between two skin combinations with clothing ensembles decreased with increasing clothing ensemble layer. In a non-isothermal condition, the total Evaporative Resistance calculated by option 1 was more accurate than value obtained by option 2, which was due to lower ambient temperature and condensation between each adjacent layer. (Less)
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Initial, transient and steady state Evaporative Resistance of impermeable protective clothing
2006Co-Authors: Chuansi Gao, Ingvar HolmérAbstract:The measured water vapour Resistances of clothing ensembles differ among laboratories particularly for impermeable clothing. Due to the moisture transfer in the clothing ensemble, Evaporative heat losses in initial, transient and steady state phases are different. The purpose of this study was to investigate moisture absorption inside underwear and outer layer as a function of time, to quantify the difference of water vapour Resistance of protective clothing (impermeable outer layer and cotton underwear) in initial, transient and steady state. Manikin Tore was used by wearing wet ‘skin’ to simulate sweating. The Evaporative Resistance is found to be more than two times higher in the initial phase than that in the saturation phase. The moisture content is gained exponentially in the clothing ensemble. On the contrary, mass loss directly from the wet skin decreases exponentially. These may partly explain the poor reproducibility while measuring the Evaporative Resistance of impermeable clothing for a short period. (Less)
Xiaoming Qian - One of the best experts on this subject based on the ideXlab platform.
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Thermal and Wet Comfort of Fabrics Based on Fractal Dimension of Silicone Coating
Journal of Engineered Fibers and Fabrics, 2018Co-Authors: Yunlong Shi, Liang Wang, Wenhuan Zhang, Xiaoming QianAbstract:In this paper, thermal and wet comforts of silicone coated windbreaker shell jacket fabrics were studied. Both thermal insulation and Evaporative Resistance of fabric increased with an increase in coating area due to the barrier effect of the silicone coating layer. Moreover, the coated fabrics with self-similar structures showed different thermal insulation and Evaporative Resistance under the same total coating area. Fractal theory was used to explain this phenomenon. Optimal thermal-wet comfort properties were obtained when the fractal dimension (D=1.599) was close to the Golden Mean (1.618). When the fractal dimension of coating was lower than 1.599, fabric warmth retention was not high enough. In contrast, fabric Evaporative Resistance was beyond the value at which people would feel comfortable when the fractal dimension was greater than 1.599.
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Effect of non-uniform skin of “Walter” on the Evaporative Resistance and thermal insulation of clothing
International Journal of Clothing Science and Technology, 2017Co-Authors: Yunlong Shi, Liang Wang, Xiaoming QianAbstract:Purpose The purpose of this paper is to compare the Evaporative Resistance and thermal insulation of clothing measured by thermal manikin “Walter” using uniform and non-uniform skin. Design/methodology/approach The non-uniform skin with different perspiration rates was made by laminating a silicone layer on the inner side of a uniform skin. The thermal manikin was then covered with prepared non-uniform skin as well as uniform one. Four types of clothing ensembles were tested. Findings The relative intensity of perspiration rate was realized in different part of “Walter” skin, which was close to the perspiration rate of human being. There was a strong correlation between uniform skin and non-uniform skin. The thermal insulation and Evaporative Resistance of clothing measured on the non-uniform skin were higher than the ones determined on the uniform skin. However, their moisture permeability index showed the reversed tendency. Research limitations/implications The implication of the research is to investigate the differences between uniform skin and non-uniform skin for manikin “Walter.” This is possibly useful in correcting and predicting more accurate thermal insulation and Evaporative Resistance of clothing measured by “Walter” with a uniform skin in future. Originality/value It was more accurate using non-uniform skin in evaluating thermal and wet comfort comparing to uniform skin.
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Effect of Garment Fit on Thermal Insulation and Evaporative Resistance
Textile Research Journal, 2004Co-Authors: Y S Chen, Xiaoming Qian, W ZhangAbstract:This paper reports on an experimental investigation of the effects of garment fit on clothing thermal insulation and moisture vapor Resistance, both of which increase with the thickness of the air gap between the garment and the body when the air gap is small. The rate of increase gradually decreases as the air gap becomes thicker, and is much less than the theoretically ideal still air due to natural and forced convection. When the air gap exceeds a certain value, thermal insulation and vapor Resistance may decrease with increases in the air gap. Thermal insulation and moisture vapor Resistance reach a maximum at a certain air gap thickness depending on fabric properties, wind conditions, and garment fit. Tighter fitting garments are preferable to keep the body warm in windy conditions.
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New functions and applications of walter, the sweating fabric manikin.
European Journal of Applied Physiology, 2004Co-Authors: Xiaoming QianAbstract:In this paper, latest developments on Walter, a sweating fabric manikin, are reported. These include the improved simulation of “walking motion”, the design and construction of an automated water supply, and real-time measurement of Evaporative water loss and regulation of “skin” temperature through the regulation of the pumps inside the manikin body. Testing of commercial garment ensembles showed that the measurement of thermal insulation and moisture-vapour Resistance of clothing is very reproducible with the coefficient of variation being generally less than 5%. It was also shown that, in addition to the thermal insulation and moisture-vapour Resistance, the percentage of moisture accumulation within clothing is a very useful parameter of clothing comfort. The improved manikin has been used to investigate the effects of walking motion on thermal insulation and Evaporative Resistance of clothing. The trend of the effects of walking speed up to 1.13 m s−1 for the nude manikin and when it was wearing garments of different sizes are reported.