关键词: 通风开口, 计算流体力学(CFD), 三维数值模型, 气流流场, 热分布

Abstract: To more intuitively investigate the impact of ventilation opening design in outdoor jackets on the temperature distribution of human skin and airflow circulation inside the clothing this study employed an advanced Computational Fluid Dynamics CFD method to conduct a systematic numerical simulation study on the thermal environment regulation performance of outdoor jackets.Initially a standard three-dimensional numerical model was established encompassing both the human body's geometric structure and the outdoor jacket clothing system.The model took into full consideration the hierarchical structure of the clothing and the configuration of air gaps thereby highly replicating the real-life scenario of a human wearing an outdoor jacket.The geometric construction in the model not only included the human body's surface contours but also refined the spatial characteristics of the areas where the clothing fits snugly and loosely against the body in an attempt to simulate the air layer state between the clothing and the skin during human movement as closely as possible.The simulation results were rigorously validated against experimental data in this paper.By comparing the simulated results with the measured average skin surface temperature and heat flux data from the experiments it was found that the maximum deviation between the two did not exceed 5% indicating that the established CFD model possessed good accuracy and reliability.This validation process not only enhanced the credibility of the simulation method but also laid a solid theoretical foundation for the subsequent systematic analysis of ventilation opening design parameters.Based on the model validation this paper further analyzed the regulatory mechanisms of ventilation openings distributed at different locations of outdoor jackets on airflow circulation inside the clothing and heat distribution on the skin surface.The study revealed the following findings firstly underarm ventilation openings demonstrated significant advantages in improving airflow circulation and heat dissipation in the underarm area.Due to the restrictive fit of the clothing in this region the air exchange efficiency is generally low.However after setting up dedicated underarm openings the local maximum air convection velocity could reach 2.87m/s significantly promoting the expulsion of hot air and the intake of cool air.As a result the average skin temperature in the underarm area was effectively reduced to 31.57℃ greatly enhancing local thermal comfort.Secondly ventilation openings located on the chest and abdomen had a remarkable effect in enhancing the heat dissipation performance of the anterior trunk region.These areas are typically the windward side and are prone to forming natural ventilation paths.After installing ventilation structures the airflow within the clothing could be accelerated.However the impact of such openings on areas like the underarms side waist and back was relatively limited.Further analysis also indicated that the temperature changes in the abdominal and side waist regions were relatively balanced with the 3# and 4# opening layouts showing the most significant cooling effects in these areas but they had a weaker impact on improving airflow circulation in the underarms demonstrating regional differences in ventilation efficiency.In addition ventilation openings on the back primarily affected airflow and thermal regulation in the back and waist regions while the openings on the chest and abdomen had a minimal impact on these areas reflecting the spatial specificity of back ventilation.In summary through highly realistic CFD simulations and experimental validations this paper systematically unveiled the inherent interaction mechanisms between the different positions of ventilation openings in outdoor jackets and the thermal regulation efficacy inside the clothing.The research findings not only clearly demonstrated how the inner clothing microclimate affects human thermal comfort but also explicitly pointed out the significant spatial specificity in the layout of ventilation openings.Reasonably designing and optimizing the arrangement structure of ventilation openings can achieve targeted cooling and enhanced airflow in specific areas which is of great significance for improving overall wearing comfort.Especially under complex outdoor environmental conditions such as high temperatures high humidity or intense physical activities scientifically arranging ventilation structures will significantly enhance the functionality and practicality of outdoor jackets.The outcomes of this study can provide theoretical foundations and practical guidance for the design of high-performance outdoor clothing.Meanwhile they meet the diverse needs of different populations regarding thermal comfort and ventilation performance of clothing opening up new avenues for personalized and refined clothing structure design in the future.

Key words: ventilation opening, Computational Fluid Dynamics（CFD）, three-dimensional numerical model, airflow field, heat distribution