Modeling steam heat transfer in thermal protective clothing under hot steam exposure

2018 ◽  
Vol 120 ◽  
pp. 818-829 ◽  
Author(s):  
Yun Su ◽  
Rui Li ◽  
Guowen Song ◽  
Jun Li ◽  
Chunhui Xiang
Keyword(s):  
Heat Transfer ◽  
Protective Clothing ◽  
Thermal Protective Clothing ◽  
Steam Heat

scholarly journals Effect of Compression on Contact Heat Transfer in Thermal Protective Clothing Under Different Moisture Contents

2019 ◽  
Vol 38 (1) ◽  
pp. 19-31 ◽  
Author(s):  
Yun Su ◽  
Rui Li ◽  
Jie Yang ◽  
Guowen Song ◽  
Jun Li
Keyword(s):  
Heat Transfer ◽  
Moisture Content ◽  
Protective Clothing ◽  
Transfer Efficiency ◽  
Protective Level ◽  
Contact Heat ◽  
Contact Heat Transfer ◽  
Heat Transfer Efficiency ◽  
Skin Contact ◽  
Thermal Protective Clothing

Contact burns pose a serious threat on firefighters’ health, safety, and job performance. The objective of the study was to analyze the effects of compression and moisture content on thermal protective performance of clothing. Skin-simulant sensor and Pennes bio-heat transfer model were used to predict time to cause skin contact burn. A new index (heat transfer efficiency) was proposed to examine the effects of applied pressure and moisture level on the contact heat transfer in the thermal protective clothing. It was demonstrated that the addition of moisture nonlinearly decreased the thermal protective level of clothing. The fabric thickness was greatly decreased by the compression, but the thermal protective level presented no significant difference between two kinds of pressures. The heat transfer efficiency was an effective index for evaluating the contact heat transfer, which was determined by the basic properties of fabric, the moisture content, and the pressure level. The conclusions from this study could contribute to understanding the effects of compression and moisture on the contact heat transfer, thus providing the principle of thermal protection against skin contact burns.

scholarly journals Application of Nanofiber Technology to Nonwoven Thermal Insulation

2007 ◽  
Vol 2 (2) ◽  
pp. 155892500700200 ◽  
Author(s):  
Phillip W. Gibson ◽  
Calvin Lee ◽  
Frank Ko ◽  
Darrell Reneker
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Radiative Heat Transfer ◽  
Protective Clothing ◽  
Radiative Heat ◽  
Glass Fibers ◽  
Small Diameter ◽  
Cold Environments ◽  
Thermal Protective Clothing ◽  
Biological Protection

Nanofiber technology (fiber diameter less than 1 micrometer) is under development for future Army lightweight protective clothing systems. Nanofiber applications for ballistic and chemical/biological protection are being actively investigated, but the thermal properties of nanofibers and their potential protection against cold environments are relatively unknown. Previous studies have shown that radiative heat transfer in fibrous battings is minimized at fiber diameters between 5 and 10 micrometers. However, the radiative heat transfer mechanism of extremely small diameter fibers of less than 1 micrometer diameter is not well known. Previous studies were limited to glass fibers, which have a unique set of thermal radiation properties governed by the thermal emissivity properties of glass. We are investigating the thermal transfer properties of high loft nanofiber battings composed of carbon fiber and various polymeric fibers such as polyacrylonitrile, nylon, and polyurethane. Thermal insulation battings incorporating nanofibers could decrease the weight and bulk of current thermal protective clothing, and increase mobility for soldiers in the battlefield.

scholarly journals Simulations of Heat Transfer through Multilayer Protective Clothing Exposed to Flame

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Adam K. Puszkarz ◽  
Waldemar Machnowski
Keyword(s):  
Heat Transfer ◽  
Computer Aided Design ◽  
Protective Clothing ◽  
Three Dimensional ◽  
Woven Fabrics ◽  
Nonwoven Fabrics ◽  
Thermal Protective Clothing ◽  
Simulation Results ◽  
Multilayer Assemblies ◽  
The Individual

AbstractIn this paper, the safety and thermal comfort of protective clothing used by firefighters was analyzed. Three-dimensional geometry and morphology models of real multilayer assemblies used in thermal protective clothing were mapped by selected Computer-Aided Design (CAD) software. In the designed assembly models, different scales of the resolution were used for the particular layers – a homogenization for nonwoven fabrics model and designing the geometry of the individual yarns in the model of woven fabrics. Then, the finite volume method to simulate heat transfer through the assemblies caused by their exposure to the flame was applied. Finally, the simulation results with experimental measurements conducted according to the EN ISO 9151 were compared. Based on both the experimental and simulation results, parameters describing the tested clothing protective features directly affecting the firefighter’s safety were determined. As a result of the experiment and simulations, comparable values of these parameters were determined, which could show that used methods are an efficient tool in studying the thermal properties of multilayer protective clothing.

scholarly journals Heat Transfer Model of Multilayer Thermal Protective Clothing for High-Temperature Operation

2019 ◽  
Vol 13 (11) ◽  
pp. 21
Author(s):  
Man-Jing Li ◽  
Mao Zhu ◽  
Jia-Xu Han ◽  
Yuan-Biao Zhang
Keyword(s):  
Heat Transfer ◽  
Heat Conduction ◽  
Steady State ◽  
High Temperature ◽  
Protective Clothing ◽  
Heat Transfer Model ◽  
Heat Radiation ◽  
Transfer Model ◽  
Thermal Protective Clothing ◽  
High Temperature Operation

The thermal protective clothing for high-temperature operation usually consists of three-layer fabrics and a gap called the air layer or Layer IV between Layer III and skin. In order to design more effective thermal protective clothing at less cost, based on the heat transfer principles, we establish heat transfer models of fabrics and air layer, which are one-dimensional nonlinear partial differential equations with constant coefficients. In the three-layer fabrics, we consider the effects of heat conduction and heat radiation in Layer I but only consider heat conduction in Layer II and Layer III. Furthermore, the heat transfer model of Layer IV is decoupled and simplified to steady-state heat conduction in Layer IV and radiation heat transfer on surface of Layer IV. According to the explicit difference schemes for the models, we use the parameters in an experiment which puts a thermal manikin in high-temperature environment for some time and measures the temperature of lateral skin at regular time, to solve the models and calculate the temperature of each layer. With MATLAB, the visual interface of three-dimensional temperature distribution is provided, which is reference for functional design of thermal protective clothing. We also compare the simulation result of skin surface with the experimental data. The results show that at the same position, the temperature rises over time but with decreasing rate and finally reaches the steady state. Moreover, at one moment after reaching the steady state, the temperature has a gradual decrease with the increase of distance from the external environment.

Development and application of numerical model of thermal sensors for thermal protective clothing evaluation based on CFD simulation

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Yuqi Tang ◽  
Zhantong Mao ◽  
Anni Li ◽  
Lina Zhai
Keyword(s):  
Heat Transfer ◽  
Thermal Properties ◽  
Numerical Model ◽  
Protective Clothing ◽  
Thermal Sensor ◽  
Thermal Sensors ◽  
Content Type ◽  
Copper Sensor ◽  
Thermal Protective Clothing ◽  
Heat Transfer Simulation

PurposeThe purpose of this paper is to study the heat transfer effect of copper sensor and skin simulant on skin.Design/methodology/approachFor the sensor, the physical and mathematical models of the thermal sensors were used to obtain the definite conditions in the heat transfer process of the sensor, and the heat transfer models of the two sensors were developed and solved respectively by using ANSYS WORKBENCH 19.0 software. The simulation results were compared with the experimental test results. For the skin, the numerical model of the skin model was developed and calculated. Finally, the heat transfer simulation performance of the two sensors was analyzed.FindingsIt is concluded that the copper sensor is more stable than the skin simulant, but the material and structure of the skin simulant is more suitable for skin simulation. The skin simulant better simulates the skin heat transfer. For all the factors in the model, the thermal properties of the material and the heat flux level are the key factors. The convective heat transfer coefficient, radiation heat transfer rate and the initial temperature have little influence on the results, which can be ignored.Research limitations/implicationsThe results show that there are still some differences between the experimental and numerical simulation values of the skin simulant. In the future, the thermal parameters of skin simulant and the influence of the thermocouple adhesion should be further examined during the calibration process.Practical implicationsThe results suggest that the skin simulant needs to be further calibrated, especially for the thermal properties. The copper sensor on the flame manikin can be replaced by the skin simulant with higher accuracy, which will be helpful to improve the accuracy of performance evaluation of thermal protective clothing.Social implicationsThe application of computational fluid dynamics (CFD) technology can help to analyze the heat transfer simulation mechanism of thermal sensor, explore the influence of thermal performance of thermal sensor on skin simulation, provide basis for the development of thermal sensor and improve the application system of thermal sensor. Based on the current research status, this paper studies the internal heat transfer of the sensor through the numerical modeling of the copper sensor and skin simulant, so as to analyze the effect of the sensor simulating skin and the reasons for the difference.Originality/valueIn this paper, the sensor itself is numerically modeled and the heat transfer inside the sensor is studied.

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