Comparative analysis of different shape ventilation elements for protective clothing

Janushevskis, Alexander; Vejanand, Sanjay-Rajni; Gulevskis, Agris

doi:10.22616/erdev.2022.21.tf052

Cited by 3 publications

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“…4. Model design of body and jacket (elliptical) [15]Table 1 Material Properties [16; 17]Material propertyHuman body Jacket Average density (kg•m -3 ) 985 1420 Specific heat (J•kg -1 •K -1 ) 3500 1140 Thermal conductivity (W•m -1 •K -1 ) 0.21 0.261 Assumptions/considerations in the Flow Simulation[15]:• No air passes from the top and bottom part of the jacket (considered as closed); this is to study the effectiveness of the ventilation. • The top and bottom parts in simulation have outer environmental effects.• Radiation is not considered in the study, as the heat loss by radiation will be the same in all cases.…”

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Shape optimization of ventilation elements for protective clothing by using metamodeling approach

Janushevskis

Vejanand

Gulevskis

2023

22nd International Scientific Conference Engineering for Rural Development Proceedings

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There are different types of protective clothing available to protect human body from different external conditions such as rain, dust, direct sun radiation, insect access and their bites. The problem of overheating of the body may arise when such proactive clothing is required to wear in warm environment or heavy workload conditions. This is because the outer layer of cloth lacks sufficient air permeability, which causes the accumulation of warm and moist air at the body and causes discomfort. To enhance air exchange, various closable vents and open spaces of clothing have been developed. However, this only results in a partial improvement in air exchange, and reducing mechanical strength of the clothing. The mechanical strength of the clothing can be increased by attaching appropriate ventilation elements at the inner side of ventilation holes, which may permit proper air exchange as well as restrict direct access of insects to the body. The design of elements involving fluid flows usually is based on time-consuming Computational Fluid Dynamics (CFD) simulations. In this paper metamodeling approach different order polynomial local and global as well as kriging approximations are compared for shape optimization purposes of ventilation elements. The main goal is to identify the geometrical shape of the element that causes the least amount of flow energy losses along the cell flow channel, which can also be known from pressure difference. For this a multistep procedure was realized to achieve the best results. 1) Planning the position of control points of Non-Uniform Rational B-Splines (NURBS) for obtaining elements with a smooth shape. 2) Building geometrical models using Computer Aided Design (CAD) software SolidWorks in conformity with the design of the experiment. 3) Calculation of responses for a complete model using Computer Aided Engineering (CAE) software SolidWorks Flow Simulation. 4) Building metamodels for responses based on the computer experiment. 5) Using metamodels for shape optimization. 6) Validating the optimal design using CAE software for the complete model.

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confidence: 99%

Shape optimization of ventilation elements for protective clothing by using metamodeling approach

Janushevskis

Vejanand

Gulevskis

2023

22nd International Scientific Conference Engineering for Rural Development Proceedings

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Selection of Appropriate Criteria for Optimization of Ventilation Element for Protective Clothing Using a Numerical Approach

Vejanand,

Janushevskis,

Vaicis

2024

Computation

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While there are multiple methods to ventilate protective clothing, there is still room for improvement. In our research, we are using ventilation elements that are positioned at the ventilation holes in the air space between the body and clothing. These ventilation elements allow air to flow freely while preventing sun radiation, rain drops, and insects from directly accessing the body. Therefore, the shape of the ventilation element is crucial. This led us to study the shape optimization of ventilation elements through the utilization of metamodels and numerical approaches. In order to accomplish the objective, it is crucial to thoroughly evaluate and choose suitable criteria for the optimization process. We know from prior research that the toroidal cut-out shape element provides better results. In a previous study, we optimized the shape of this element based on the minimum pressure difference as a criterion. In this study, we are using different criteria for the shape optimization of ventilation elements to determine which are most effective. This study involves a metamodeling strategy that utilizes local and global approximations with different order polynomials, as well as Kriging approximations, for the purpose of optimizing the geometry of ventilation elements. The goal was achieved by a sequential process. (1) Planning the position of control points of Non-Uniform Rational B-Splines (NURBS) in order to generate elements with a smooth shape. (2) Constructing geometric CAD models based on the design of experiments. (3) Compute detailed model solutions using SolidWorks Flow Simulation. (4) Developing metamodels for responses using computer experiments. (5) Optimization of element shape using metamodels. The procedure is repeated for six criteria, and subsequently, the results are compared to determine the most efficient criteria for optimizing the design of the ventilation element.

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Analysis of Different Shape Ventilation Elements for Protective Clothing

Janushevskis

Vejanand

Gulevskis³

2022

Wseas Transactions on Fluid Mechanics

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People's thermoregulation may be hampered by exposure to extreme temperatures. Because of this, it is crucial to consider how fabric cooling and ventilation may affect human comfort while designing clothing. There is a demand on the market for more effective technical solutions and materials to be used in the external part of protective gear, while also ensuring the necessary ventilation even in warm environmental conditions and during heavy physical load. This is due to the growing interest in the market for efficient protection of the human body against exposure to extreme weather conditions. In this article simple elliptical model of the body and the jacket is used to reduce the complexity of the problem. Five different shapes of ventilation elements named as E1 to E5 are designed for the study and the numerical results for the pressure, temperature and heat flux are calculated using SolidWorks Flow Simulation at three different inlet air velocity of 2, 5 and 8 m/s. The acquired results display interesting flow patterns and how the ventilation elements' shapes might influence the flow at various wind velocities. The results are compared and analyzed in terms of heat flux, pressure difference and temperature difference. The main objective is to determine which element's geometrical shape gives the smallest flow energy losses in the cell flow channel. If the pressure difference is higher, flow energy losses will also be high, and if the flow energy losses are higher, the body cooling decreases. The obtained results show that pressure difference increases gradually with the increasing inlet velocity. Moreover, results also indicates how different shapes of ventilation elements can affect the flow, pressure difference and flow energy losses. Based on analysis of obtained simulation results the most perspective ventilation element is proposed.

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Comparative analysis of different shape ventilation elements for protective clothing

Cited by 3 publications

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Shape optimization of ventilation elements for protective clothing by using metamodeling approach

Shape optimization of ventilation elements for protective clothing by using metamodeling approach

Selection of Appropriate Criteria for Optimization of Ventilation Element for Protective Clothing Using a Numerical Approach

Analysis of Different Shape Ventilation Elements for Protective Clothing

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