Research progress on thermo-physiological models in the assessment of thermal stress in dressed human bodies
In firefighting and industrial scenarios,workers exposed to factors like metabolic heat production,protective clothing,and high-temperature radiation can experience a range of heat stress reactions such as increased body temperature,dehydration,fatigue,and heatstroke,potentially endangering human life.Heat stress assessment helps identify thermal risks in the work environment,allowing for the adjustment of environmental parameters to enhance safety and comfort.Additionally,improving working conditions can increase worker efficiency and overall productivity.Thermo-physiological models,known for their flexible modeling and stable prediction,are extensively used for thermal stress and safety assessments in thermal environments.This article aims to provide reference for further research on optimizing modeling methods and enhancing the predictive accuracy of thermo-physiological models,so as to advance the technology for assessing thermal stress in clothed individuals in hot environments,and establish individual protection strategies to ensure the health and safety of workers.When assessing thermal stress responses in clothed individuals in high-temperature environments,researchers primarily focus on experimental studies and predictive modeling.However,existing assessment methods have their limitations:human experiments are costly and pose safety risks;dummy tests struggle to dynamically respond to environmental changes;and current thermal stress prediction models are more suited to steady-state thermal environments,lacking efficacy in complex thermal scenarios.These issues underscore the need for more refined and comprehensive tools for thermal stress assessment.Consequently,the development and application of thermo-physiological models have become a significant research direction in assessing human thermal stress in high-temperature environments.In practice,the modeling and simulation of the human body,the heat transfer model between the human body and the environment,and the simulation of clothing heat transfer all impact the assessment outcomes.In human body modeling,there is an increasing focus on detailed physiological structure portrayal and the complexity of simulating thermal regulatory mechanisms.Recent studies have developed extended human models suitable for high-temperature environments,especially for individuals working in non-uniform thermal conditions,considering both the characteristics of the subjects and the environment.In constructing the human-environment heat transfer model,a comprehensive analysis of heat and mass transfer between the environment and the human body is conducted,and numerical simulations are employed to determine the heat transfer coefficients of various human body surfaces.Two primary strategies are employed in clothing heat transfer simulation:incorporating simplified thermal parameters of clothing or integrating thermo-physiological models with dynamic clothing models.Building a human thermo-physiological model is an effective method for assessing thermal stress in clothed individuals in high-temperature environments,offering advantages such as stability,efficiency and flexibility.In the future,research can be carried out from the following directions.First,new algorithms can be developed based on research in physiology and neuroscience to more accurately simulate the actual details of human body temperature regulation in high-temperature environments.Second,integrating dynamic heat transfer coefficients into human-environment heat transfer models presents challenges,necessitating overcoming differences between CFD models and human thermo-physiological models,and applying suitable numerical methods and grid resolutions to capture the complex heat transfer and flow processes in high temperatures.Third,it is necessary for future research to focus on enhancing the integration of clothing models with thermo-physiological models,improving the precision of clothing models by considering material properties and fabric structures,and developing comprehensive human-clothing-environment models for high-temperature settings,taking into account key factors such as environmental temperature and humidity,wind speed,thermal radiation,and human dynamics.