Study of the Thermal Environment around a Human Body : A Review

Computational fluid dynamics (CFD) simulations of thermal manikins can provide detailed information which it is impossible to obtain from experiments. In this review several issues from CFD studies of thermal manikins are discussed, such as geometric complexity of computational thermal manikins (CTMs), selection of turbulence models, grid generation and boundary conditions. Calculation of CTMs with simple geometry requires less computational resource but a more anthropomorphic geometry can provide more accurate results. In the simulations using complex geometric representations of the human body the computational domain is discretised by body-fitted co-ordinates or unstructured grids. The total number of cells can reach the quantitative magnitude of 1 million. The simulation results about airflow field, radiative and convective heat transfer and contaminant distribution from different researchers are compared. Further developments in the use of these simulations are proposed. Introduction An important goal in indoor air quality (IAQ) and thermal comfort research is an enhanced understanding of the relationship between the human body and the surrounding environment. Human bodies, in this respect, play a central role in indoor environments. To facilitate studies, thermal manikins were introduced at least a half century ago. Thermal manikins are heated dummies which were originally developed to measure the thermal insulation of clothing. In 1977, Mihira et al. [1] developed a thermal manikin not only for clothing insulation measurement but also for the evaluation of thermal environments. Later more complex thermal manikins were used to study thermal environments of human bodies in the indoor environment [2–4]. Although experimental researches using thermal manikins provide valuable information about airflow velocities, temperature and pollutant concentration, some other detailed information, such as the air flow field in the close vicinity of a person and the ratio between the amount of radiative heat transfer and convective heat transfer between human body and surroundings, cannot be obtained by experiments. During the last few years CFD technology has progressed and made it possible to analyse the micro-climate around a human body. A Dr N.P. Gao Department of Building Services Engineering The Hong Kong Polytechnic University, Hung Hom, Kowloon Hong Kong, China Tel. 852 2766 4698. E-mail [email protected] © 2005 Sage Publications DOI: 10.1177/1420326X05050132 Accessible online at: www.sagepublications.com Environment Review Paper Indoor Built Environ 2005 14;1:5–16 Accepted: June 27, 2004 CFD Study of the Thermal Environment around a Human Body: A Review