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.

Impact of Pulse Quenching Effect on Sensitive Area at Advanced Technologies

2013 ◽  
Vol 392 ◽  
pp. 693-696
Author(s):  
Wen Tao Xu ◽  
Yang Guo ◽  
Yan Kang Du
Keyword(s):  
Computer Aided Design ◽  
Three Dimensional ◽  
Sensitive Area ◽  
Isolation Technique ◽  
Quenching Effect ◽  
Advanced Technologies ◽  
Computer Aided ◽  
Simulation Results ◽  
Aided Design ◽  
The Impact

The impact of pulse quenching effect on the sensitive area is evaluated by using three-dimensional technology computer-aided design (TCAD) numerical simulation. Simulation results present that the pulse quenching effect could effectively reduce the sensitive area of PMOS transistors. By adopting the off-state gate isolation technique, the sensitive area is further reduced.

Numerical Analysis on the Temperature Field in Laser-Plasma Hybrid Welding of an Aluminum Alloy

2008 ◽  
Vol 580-582 ◽  
pp. 279-282
Author(s):  
Zhi Ning Li ◽  
Bao Hua Chang ◽  
Dong Du ◽  
Hua Zhang
Keyword(s):  
Heat Transfer ◽  
Aluminum Alloy ◽  
Laser Plasma ◽  
Three Dimensional ◽  
Temperature Fields ◽  
Transfer Model ◽  
Heat Sources ◽  
Hybrid Welding ◽  
Plasma Arc ◽  
Simulation Results

A three dimensional heat transfer model on laser-plasma hybrid welding has been proposed, that takes into account the interaction between laser beam and plasma arc. Through FEM computation, the temperature fields were computed and analyzed for an Al-Li alloy during laserplasma hybrid welding with different distances between the two heat sources. The simulation results are in agreement with the experimental results.

Simulation and Identification of Nonstationary Heat Transfer in a Nonuniform Friction Contact

1993 ◽  
Vol 115 (2) ◽  
pp. 299-306 ◽  
Author(s):  
O. Bogatin ◽  
I. Chersky ◽  
N. Starostin
Keyword(s):  
Heat Transfer ◽  
Numerical Simulation ◽  
Three Dimensional ◽  
Unit Element ◽  
Separation Coefficient ◽  
Friction Contact ◽  
Nonstationary Heat Transfer ◽  
Thermal Fields ◽  
Simulation Results ◽  
Marching Method

The results of numerical simulation of nonstationary thermal fields in cylindrical friction junctions are presented. On the basis of the marching method, a numerical algorithm which imposes no restrictions on the value of heat flow separation coefficient is constructed. Simulation results are given for different bearing designs both for the two and three-dimensional cases. Using the developed algorithm as a base, a method allowing for reconstruction of heat release and, hence, friction moment values from temperature measurements in the stationary unit element is suggested. Reliability of the results is proved by experiments.

scholarly journals Influential Parameters of Starching Process on Mechanical Properties of Yarns Intended for Multifunctional Woven Fabrics for Thermal Protective Clothing

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 73
Author(s):  
Ivana Schwarz ◽  
Stana Kovačević ◽  
Ivana Vitlov
Keyword(s):  
Mechanical Properties ◽  
Abrasion Resistance ◽  
Protective Clothing ◽  
Woven Fabrics ◽  
Polymer Fibers ◽  
Yarn Properties ◽  
Thermal Protective Clothing ◽  
Influential Parameters ◽  
Linear Regressions ◽  
Mass Concentrations

The investigation of influential parameters of the starching process on mechanical properties of yarns intended for multifunctional woven fabrics for thermal protective clothing was performed on four different yarn samples starched on an innovative starching machine, adapted to industrial starching conditions. The starching was conducted with two different processes with different starch mass concentrations: the standard starching process and a newer starching process (with yarn prewetting). Based on the results obtained, it can be concluded that starching positively affects all the properties of tested samples and that the increase of starch mass concentration is not accompanied by the improvement of those yarn properties. Synthetic polymer fibers that achieve satisfactory yarn strength need to be starched with lower starch mass concentrations in order to retain the breaking properties and to be protected from abrasion and static electricity, which occurs during the weaving process. The yarn prewetting starching process shows significantly better results than the standard starching process, especially for aramid yarns, where abrasion resistance increased from 42 to 135%. Therefore, we can conclude that the goal of starching such yarns is aimed at increasing the wear resistance. Linear regressions and correlations between the values of breaking properties and abrasion resistance obtained by the testing and their values that were estimated by the analysis show a high correlation coefficient.

Heat Transfer Investigation of an Additively Manufactured Minichannel Heat Exchanger

2019 ◽  
Author(s):  
Hamidreza Rastan ◽  
Amir Abdi ◽  
Monika Ignatowicz ◽  
Bejan Hamawandi ◽  
Poh Seng Lee ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Heat Exchanger ◽  
Single Phase ◽  
Three Dimensional ◽  
Heat Fluxes ◽  
Experimental Results ◽  
Working Fluid ◽  
Minichannel Heat Exchanger ◽  
Simulation Results ◽  
Good Agreement

Abstract This study investigates the thermal performance of laminar single-phase flow in an additively manufactured minichannel heat exchanger both experimentally and numerically. Distilled water was employed as the working fluid, and the minichannel heat exchanger was made from aluminum alloy (AlSi10Mg) through direct metal laser sintering (DMLS). The minichannel was designed with a hydraulic diameter of 2.86 mm. The Reynolds number ranged from 175 to 1360, and the heat exchanger was tested under two different heat fluxes of 1.5 kWm−2 and 3 kWm−2. A detailed experiment was conducted to obtain the thermal properties of AlSi10Mg. Furthermore, the heat transfer characteristics of the minichannel heat exchanger was analyzed numerically by solving a three-dimensional conjugate heat transfer using the COMSOL Multiphysics® to verify the experimental results. The experimental results were also compared to widely accepted correlations in literature. It is found that 95% and 79% of the experimental data are within ±10% range of both the simulation results and the values from the existing correlations, respectively. Hence, the good agreement found between the experimental and simulation results highlights the possibility of the DMLS technique as a promising method for manufacturing future multiport minichannel heat exchangers.

Cooling Flow Simulation in the Enclosure of Mobile Generator

2004 ◽  
Author(s):  
J. Xie ◽  
R. S. Amano
Keyword(s):  
Heat Transfer ◽  
Pressure Drop ◽  
Flow Rate ◽  
Hot Spots ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Cooling Flow ◽  
Simulation Results ◽  
Design Factors ◽  
Flow Study

A thermal and airflow simulation model is developed for three-dimensional cooling flow study of ventilation and heat transfer inside a mobile generator’s enclosure. The purpose of this design is to achieve better sound attenuation while keeping proper cooling of the engine and generator. This paper focuses its objectives on the adjustment and improvement of cooling performances of some design factors like vent size, vent positions, fan’s flow rate and airflow route based on the CFD approach. A zero-equation HVAC turbulence model was employed and the simulation results were compared with the standard k-ε model. Numerical results show that the proper distribution in the intake vents helps in achieving uniform cooling flow distributions by avoiding the occurrence of hot spots on the engine and generator surfaces. Pressure drop through muffler and radiator are both important factors. Effective flow path arrangement is also found to be one of the most fatal factors in the thermal and noise management.

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