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.

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.