Moisture transfer of the clothing–human body system during continuous sweating under radiant heat

Abstract

Mass transfer due to perspired moisture in a clothing system is critical for the understanding of thermo-physiology and thermal protection of a clothed body. Previous studies usually investigated moisture transfer without considering the effect of liquid sweating or external heat hazards. To understand the mechanisms of sweat evaporation, accumulation and dripping with continuous sweating under radiant heat, a multi-phase experiment was designed with a sweating Torso. The concept of clothed wettedness was proposed to understand sweat evaporation of the clothed body. Results showed that the evaporation rate of the clothed body increased with increasing perspiration rate and the rate increase can be explained by the material properties (e.g., material composition, hydrophilicity and evaporative resistance ([Formula: see text])), which affected the sweat accumulation ability. Results also demonstrated a dual relationship of [Formula: see text] with the evaporation rate of the clothed body. Firstly, the evaporation rate was increased for greater [Formula: see text] due to the higher moisture accumulation. Secondly, when [Formula: see text] exceeded a certain value, the evaporation rate decreased with greater [Formula: see text] due to the reduction in the mass transfer coefficient. For radiant heat exposure, evaporated sweat may condense on the skin surface, decreasing the evaporation rate and increasing the dripping rate. The sweat transfer process was also investigated in detail by the combined analysis of the sweat transfer rate and the evaporative cooling efficiency. This study provides insights into how continuous liquid sweat transfers and evaporates in the clothed body and its interaction with clothing material and environment radiant heat, contributing to the understanding of thermo-physiological burden and thermal protection of the clothed body with intensive activities.

Characterization and Modeling of Thermal Protective and Thermo-Physiological Comfort Performance of Polymeric Textile Materials—A Review

“…In addition, fabric R ct and R et are important property along with fabric thickness and emissivity when assessing metabolic heat dissipation and radiant heat gain while the wearers are sweating profusely in a working condition. In another study, Guan et al (2019) [ 38 ] indicated that sweat evaporation rate through the fabrics increases for fabrics with high evaporative resistance when high amount of moisture accumulated within a hydrophilic fabric; however, after a certain time, the evaporation rate decreased for the fabric due to the reduction in the mass transfer coefficient of the fabrics.…”

“…However, these tests are fabric destructive in nature, time consuming, and/or expensive to carry out on a regular basis [ 23 , 24 , 25 ]. As a result, previous studies have focused on characterizing and developing empirical models to predict the protective and comfort performance based on physical properties of the fabrics [ 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 , 58 , 59 , 60 , 61 , 62 , 63 ]. For this, first, significant fabrics’ properties that affect the protective and comfort performance of fabrics were identified.…”

Characterization and modeling of thermal protective fabrics under Molotov cocktail exposure

“…In the manufactured workwear for high-risk sectors' employees, layered fabric systems are generally used. These fabric systems consist of different types of high-performance fabrics (an outer shell, a moisture barrier, and/or a thermal liner) in an assembly [28][29][30]. In this study, the commercially available and commonly used high-performance fabrics in the manufacturing of thermal protective clothing were selected based on the fiber content, weave structure, mass, thickness, and air permeability ( Table 1).…”

Towards the Concurrent Optimization of the Server: A Case Study on Sport Health Simulation

“…For example, in the process of establishing the heat and moisture simulation model of clothing human body, it is necessary to understand the human physiological tissue structure and construct the simulation model of human thermal physiological regulation mechanism by comprehensively considering dozens of factors such as metabolism, blood flow, respiration, and heart rate [9,10]. It is also necessary to consider the law of conservation of mass and energy to construct the heat and moisture transfer model of clothing corresponding to human body and the interaction model between human body and clothing [11]. In order to solve a large number of partial differential equations established in the simulation model, it is necessary to introduce the finite element numerical solution method.…”