暖体假人的研究现状和应用概况

暖体假人的研究和发展已经有70多年的历史,它们被广泛地应用于分析人体热边界层和周围环境变化的测试之中,特别是服装热特性的测试以及人体在复合环境内的热通量分析。当前的暖体假人不仅可以模拟实际人体出汗,有的还具备能够模拟人体的显热散热、潜热散热、肢体活动及可呼吸、出汗等功能,作为一种近似模拟人体的实验装置。与实际人体相比较,不会像实际人体一样容易受到环境因素影响而产生的不同的心理变化,其次暖体假人的测试可靠性高,测试重复性好,还能更加真实地模拟出人体面对外界环境改变所做出的自我调整。     

暖体假人的研究现状和应用概况

暖体假人的研究和发展已经有70多年的历史,它们被广泛地应用于分析人体热边界层和周围环境变化的测试之中,特别是服装热特性的测试以及人体在复合环境内的热通量分析.当前的暖体假人不仅可以模拟实际人体出汗,有的还具备能够模拟人体的显热散热、潜热散热、肢体活动及可呼吸、出汗等功能,作为一种近似模拟人体的实验装置.与实际人体相比较,不会像实际人体一样容易受到环境因素影响而产生的不同的心理变化,其次暖体假人的测试可靠性高,测试重复性好,还能更加真实地模拟出人体面对外界环境改变所做出的自我调整.     

呼吸暖体假人的设计研发及应用展望

为研究人体微环境特征,再现人体吸入暴露过程并获得飞沫或飞沫核在呼吸道内的实际暴露水平,设计了一种新型呼吸暖体假人,首次实现呼吸暖体假人与呼吸道模型的结合。假人外形与平均人体相似,通过调节假人加热系统功率,模拟人体不同活动水平下的代谢散热;体内嵌有包含口咽模型和Weibel 0～4级模型组成的"理想呼吸道",还原吸入气流在呼吸系统内的流动特性,有效测量飞沫核在人体呼吸道的实际暴露剂量;设计研发了呼吸模拟装置,可输出接近真实人体呼吸特性的正弦曲线,通过调节参数来模拟人体不同活动状态下的呼吸特征。对假人表面温度和传热系数进行了实验测量。初步研究结果表明,假人可模拟多种活动状态下的人体代谢水平及呼吸特征,复现人体热羽流和呼吸气流共同作用下的人体微环境,可代替真人进行相关科学研究。     

暖体假人温控系统方案的研究

暖体假人是模拟人体与环境之间热湿交换的仪器设备,在服装功效研究方面有重要的应用价值。为了找出控制假人温度的最佳方案,本文提出了两种暖体假人表面温度的控制方案,PID控制和固态继电器通断控制,运用Labview软件编程及相应的硬件设备实现对暖体假人表面温度的控制,简单分析比较了两种方案的控制效果,发现PID控制可以更有效并自动地对假人温度进行控制。文章最后还提出了PID控制的改进优化方案。     

暖体假人LabVIEW测试系统程序优化

暖体假人是能够模拟真实人体散热情况的仪器设备,主要被用于服装热阻的测试和室内环境舒适度的评价。本文介绍了传统恒温控制法和恒热控制法以外的第三种暖体假人服装热阻测试方法——基于热舒适方程的变温控制法,并且编写了相应的LabVIEW程序。最后,分别用LabVIEW恒温和变温控制程序对同一服装的热阻进行测试并比较其结果。     

暖体假人表面电热丝的敷设方案论证

暖体假人是准确模拟真人热湿环境的实验设备,可以用来测试服装热阻,对假人表面的温度均匀性要求较高,假人的发热量大多靠在其表面敷设电热丝来实现。以控制功率法来控制电热丝的敷设间距、长度等指标,对其敷设电热丝的方案进行了分析论证。结果显示,假人表面的温度波动在±0.2℃的温差范围内。     

暖体假人表面温度的PID控制

暖体假人是模拟真人与环境间热湿交换的实验设备,可以用它来测试服装热阻,对假人表面温度的稳定性和准确度要求极高。为了达到稳定和准确两个要求,本文运用Labview软件编写了无控制输出处理和有控制输出处理两个PID控制算法程序,提出了两种PID控制参数整定方法:试凑法和自动整定法。结果表明:有控制输出处理的PID控制算法更加稳定和准确,PID控制参数自动整定法能更全面和准确地找到最佳控制参数。     

京津地区办公建筑夏季空调环境调查研究之典型着装行为及其热学性能

采取问卷调查与实验室测试相结合的方法,获得京津地区办公建筑夏季空调环境下职员的典型着装形式为短袖+长裤,典型面料为棉织物,并采用出汗暖体假人测试出典型着装的平均热阻为0.37clo,湿阻为18.09m2·Pa/W。从减小夏季着装热阻的角度考虑,建议选用汗布、细布等热阻值更低的棉织物。典型着装的热阻比舒适标准中的标准服装热阻低0.13clo,其对应的主观温度比标准服装下高0.81℃,因此办公建筑夏季空调环境下典型着装时室内设计温度可以在目前推荐值的基础上适当提高。     

一种保温承重型混凝土空心砌块的开发与试点建筑

本文介绍一种既可用于承重墙体、又可用于非承重墙体的保温承重型混凝土空心砌块的开发与试点建筑。试点工程实践表明:该承重保温砌块的建筑设计与施工完全可按照《混凝土小型空心砌块》JGJ/T14-2004进行;外墙平均传热系数值不仅满足成都市“夏热冬冷”建筑节能标准(50%),也可达到节能率65%的要求;其节能建筑的造价比烧结空心砖结构——EPS外墙保温材料的造价低40%左右。     

防止和减轻混凝土空心砌块墙体裂缝的一些措施

1　前言在国内很多地区混凝土小型空心砌块已成为取代实心粘土砖的主导墙体材料。城市中砌块建筑可分为三大类 :一类是用混凝土小型空心砌块建造的 6～ 7层多层砌块住宅 ;第二类是用高强砌块、配筋砌体建造的高层小砌块住宅 ;第三类是用各种轻质砌块砌筑框架结构的填充墙。由于混凝土小型空心砌块墙体干缩率较砖墙体大 ,抗剪强度较砖砌体低 ,因而导致混凝土小型空心砌块墙体更容易开裂。2　混凝土小型空心砌块墙体的裂缝形态混凝土小型空心砌块墙体裂缝按其形成的原因可分为两大类 :①变形裂缝 ,包括温度裂缝、干缩裂缝 ;②受力裂缝 (主要是…     

Numerical analysis of air flow, heat transfer, moisture transport and thermal comfort in a room heated by two-panel radiators

A three-dimensional steady-state numerical analysis was performed in a room heated by two-panel radiators. A virtual sitting manikin with real dimensions and physiological shape was added to the model of the room, and it was assumed that the manikin surfaces were subjected to constant temperature. Two different heat transfer coefficients for the outer wall and for the window were considered. Heat interactions between the human body surfaces and the room environment, the air flow, the temperature, the humidity, and the local heat transfer characteristics of the manikin and the room surfaces were computed numerically under different environmental conditions. Comparisons of the results are presented and discussed. The results show that energy consumption can be significantly reduced while increasing the thermal comfort by using better-insulated outer wall materials and windows.     

Integrated thermal comfort analysis using a parametric manikin model for interactive real-time simulation

Following the work of Fiala (Fiala, D., Lomas, K., and Stohrer, M., 2001. Computer prediction of human thermoregulatory and temperature-responses to a wide range of environmental conditions. International Journal of Biometeorology, 45, 143–159) we developed and tested a parametric multi-segment manikin model as the interface between Fiala's human thermoregulation model and other computational codes for studying transient and local effects of thermal sensation and comfort perception. The model allows for motion control by transforming body parts according to an armature model which relates topological dependencies. The position of joints and decomposition into segments is chosen in terms of the settings of Fiala's model. Several faceted geometric models are available such as the NASA MSIS Standard or predefined NASTRAN geometries. The developed thermoregulation interface provides means to computational steering, i.e. to interact with an ongoing simulation. The boundary conditions, the type of clothing, or the activity level can be modified online, results are updated on a real time scale during the simulation. The visualization on the artificial skin of the manikin includes the surface/skin temperatures and the local thermal sensation votes (LTSV); likewise the predicted mean vote (PMV) and the dynamic thermal sensation (DTS) are output. The LTSV data are based on experimental data which were obtained in a test chamber involving 24 test subjects for three levels of clothing insulation and a light level of activity.     

A study on the thermal comfort in sleeping environments in the subtropics—Measuring the total insulation values for the bedding systems commonly used in the subtropics

The total thermal insulation value of a bedding system significantly affects the thermal neutral temperature for sleeping environments and is therefore an important variable in the Comfort Equation developed for sleeping environments reported in a related paper. This paper reports on the measurement of the total insulation values for a wide range of bedding systems (through different combinations of bed, bedding and its percentage coverage over a human body, and sleepwear) commonly used in the subtropical regions using a thermal manikin. The total insulation values of the measured bedding systems varied greatly from 0.90 to 4.89 clo, depending upon bedding, bed and mattress, the type of sleepwear, and percentage coverage of body surface area by bedding and bed. The use of a Chinese traditional style bed—Zongbang bed can provide less insulation than the use of the conventional mattress commonly used in Hong Kong. The use of so-called air conditioning quilt (summer quilt) cannot help lower the total insulation significantly. On the other hand, some factors such as people sweating and moisture permeability of the quilts, etc., were not considered in the current study but may be further studied in future work.     

Measurement and prediction of indoor air quality using a breathing thermal manikin

The analyses performed in this paper reveal that a breathing thermal manikin with realistic simulation of respiration including breathing cycle, pulmonary ventilation rate, frequency and breathing mode, gas concentration, humidity and temperature of exhaled air and human body shape and surface temperature is sensitive enough to perform reliable measurement of characteristics of air as inhaled by occupants. The temperature, humidity, and pollution concentration in the inhaled air can be measured accurately with a thermal manikin without breathing simulation if they are measured at the upper lip at a distance of <0.01 m from the face. Body surface temperature, shape and posture as well as clothing insulation have impact on the measured inhaled air parameters. Proper simulation of breathing, especially of exhalation, is needed for studying the transport of exhaled air between occupants. A method for predicting air acceptability based on inhaled air parameters and known exposure-response relationships established in experiments with human subjects is suggested. PRACTICAL IMPLICATIONS: Recommendations for optimal simulation of human breathing by means of a breathing thermal manikin when studying pollution concentration, temperature and humidity of the inhaled air as well as the transport of exhaled air (which may carry infectious agents) between occupants are outlined. In order to compare results obtained with breathing thermal manikins, their nose and mouth geometry should be standardized.     

CFD simulation of naked flame manikin tests of fire proof garments

The overall performance of the thermal protective clothing can only be evaluated using an assessment based on an instrumented manikin under defined, close to real-life conditions in a laboratory. However, the manikin tests can only give a few of pointwise information. This paper presents a three-dimensional transient CFD simulation of heat and mass transfer in the flame manikin test of thermal protective clothing. The used grid model, simulated from Donghua Flame Manikin, have real dimensions and accurate shape of a typical Chinese man. The solver and physical models are defined in FLUENT system and the CFD simulation of a naked flame manikin test is accomplished. By means of CFD simulation, temperature and velocity fields on the manikin surface and of the whole chamber during the process of 4-second flash fire combustion are obtained, which give well predictions to the heat flux distribution in an average sense. The cumulative curve of heat fluxes in the CFD simulation is close to the curve measured by 135 sensors in the real manikin experiment. The study could be a foundation for further study on modeling heat and mass transfer in the clothed manikin experiment and predicting skin damage accurately.     

Evaluation of comfort level in desks equipped with two personalized ventilation systems in slightly warm environments

In this work the comfort level, namely the thermal comfort, local thermal discomfort and air quality levels, in a classroom with desks equipped with two personalized ventilation systems, in slightly warm environments, is evaluated. A manikin, a ventilated classroom desk, two indoor climate analyzers, a multi-nodal human thermal comfort numerical model and a computational fluid dynamic numerical model, are used.     

Transport of particulate and gaseous pollutants in the vicinity of a human body

A uniform pollutant concentration in indoor environments can be an inappropriate representation of breathing concentration. This is especially true when local airflow in the vicinity of an occupant is dominant in transporting pollutants. The present study investigates the airflow in the vicinity of a human body, effects of respiration on breathing concentration of particulate and gaseous pollutants, and inhalation exposure in relation to source position and overall airflow patterns. It is based on experiments with a human simulator in a full-scale environmental chamber. Airflow and pollutant concentrations in the vicinity of a thermal manikin are monitored, while varying parameters including breathing, arm/hand movements, and ventilation system. Results show that breathing of a sedentary manikin has a measurable influence on the airflow in breathing zone, whereas it has very small impacts on occupant thermal plume. Also, localized hand motions have insignificant effects on the thermal plume. The results indicate that overall airflow pattern affect the inhaled particle concentrations. With highly mixed airflow in the space, relatively uniform concentration patterns occur in the occupant vicinity. However, with stratified airflow patterns, non-uniform concentration patterns are observed due to the occupant thermal plume. With a particle source at floor level and in near proximity to an occupant, inhaled particle concentrations are up to four times higher than the ambient concentrations. This finding implies that occupant thermal plume may play a significant role in transporting pollutants from floor level to the breathing zone. The non-uniform concentration observed with stratified flow also suggests caution in estimating inhalation exposure using a “well-mixed” mass balance model.     

Simulating the human body's microclimate using automatic coupling of CFD and an advanced thermoregulation model

This study aims to develop an approach to couple a computational fluid dynamics (CFD) solver to the University of California, Berkeley (UCB) thermal comfort model to accurately evaluate thermal comfort. The coupling was made using an iterative JavaScript to automatically transfer data for each individual segment of the human body back and forth between the CFD solver and the UCB model until reaching convergence defined by a stopping criterion. The location from which data are transferred to the UCB model was determined using a new approach based on the temperature difference between subsequent points on the temperature profile curve in the vicinity of the body surface. This approach was used because the microclimate surrounding the human body differs in thickness depending on the body segment and the surrounding environment. To accurately simulate the thermal environment, the numerical model was validated beforehand using experimental data collected in a climate chamber equipped with a thermal manikin. Furthermore, an example of the practical implementations of this coupling is reported in this paper through radiant floor cooling simulation cases, in which overall and local thermal sensation and comfort were investigated using the coupled UCB model.     

Performance assessment of a ductless personalized ventilation system using a validated CFD model

The aim of this study is twofold: to validate a computational fluid dynamics (CFD) model, and then to use the validated model to evaluate the performance of a ductless personalized ventilation (DPV) system. To validate the numerical model, a series of measurements was conducted in a climate chamber equipped with a thermal manikin. Various turbulence models, settings, and options were tested; simulation results were compared to the measured data to determine the turbulence model and solver settings that achieve the best agreement between the measured and simulated values. Subsequently, the validated CFD model was then used to evaluate the thermal environment and indoor air quality in a room equipped with a DPV system combined with displacement ventilation. Results from the numerical model were then used to quantify thermal sensation and comfort using the UC Berkeley thermal comfort model.     

Evaluating the performance of thermal sensation prediction with a biophysical model

Neutral thermal sensation is expected for a human body in heat balance in near‐steady‐state thermal environments. The physiological thermoneutral zone (TNZ) is defined as the range of operative temperatures where the body can maintain such heat balance by actively adjusting body tissue insulation, but without regulatory increases in metabolic rate or sweating. These basic principles led to the hypothesis that thermal sensation relates to the operative temperature distance from the thermoneutral centroid (dTNZ_op). This hypothesis was confirmed by data from respiratory climate chamber experiments. This paper explores the potential of such biophysical model for the prediction of thermal sensation under increased contextual variance. Data (798 votes, 47 participants) from a controlled office environment were used to analyze the predictive performance of the dTNZ_op model. The results showed a similar relationship between dTNZ_op and thermal sensation between the dataset used here and the previously used dataset. The predictive performance had the same magnitude as that of the PMV model; however, potential benefits of using a biophysical model are discussed. In conclusion, these findings confirm the potential of the biophysical model with regard to the understanding and prediction of human thermal sensation. Further work remains to make benefit of its full potential.