Analysis of Different Shape Ventilation Elements for Protective Clothing

Janushevskis, Alexander; Vejanand, S. Rajni; Gulevskis, Agris

doi:10.37394/232013.2022.17.14

Cited by 3 publications

(1 citation statement)

References 10 publications

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“…The comparative analysis of the different ventilation elements in our previous studies [13] showed that most perspective in sense of minimal flow losses are elements with torus shape cut-out in the core (Fig. 1).…”

Section: Model Components and Boundary Conditionsmentioning

confidence: 89%

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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Section: Model Components and Boundary Conditionsmentioning

confidence: 89%

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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Air Flow Analysis for Protective Clothing Ventilation Elements with and Without Constant Cross-Section Area Opening

Janushevskis

Vejanand

Gulevskis³

2023

Latvian Journal of Physics and Technical Sciences

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In this paper a ventilation element is designed with the constant cross-sectional area of 3.14 mm2 with the outer ring, to study the efficiency of ventilation at three different inlet air velocities (2, 5 and 8 m/s). There are five different cases analysed in the study, in which four cases are with different coordinate values of outer ring and core while the fifth case is studied with ventilation element without outer ring. The results of all five cases are analysed and compared to see the efficiency of ventilation element design. These ventilation elements are attached at ventilation hole at the inner part of the protective jacket. The attached ventilation element increases mechanical strength of the clothing by covering ventilation hole and restricting direct access of insects to the body. Moreover, ventilation elements permit smooth flow of air inside jacket. The objective is to determine which element’s geometrical configuration results in the minimum flow energy losses in the cell flow channel from the inlet to the outlet, which are represented by the pressure difference. Flow energy losses increase with increasing pressure difference (ΔP), and the body cooling reduces if the flow is weakened or there is of lost energy. SolidWorks Flow Simulation is used to calculate the pressure, temperature, and heat flux for the simplified elliptical model of the human body with a protective jacket. The obtained results are compared and analysed to study the concept of constant cross-sectional area in the design of ventilation elements with and without outer ring. The pressure and temperature difference for each case are calculated for the comparison and the obtained results show that the element design without outer ring provides better overall results and less flow energy loss in the cell flow channel than that of element design with outer ring.

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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

Cited by 3 publications

References 10 publications

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

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

Air Flow Analysis for Protective Clothing Ventilation Elements with and Without Constant Cross-Section Area Opening

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

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