Combined simulation of airflow, radiation and moisture transport for heat release from a human body

Murakami, Shuzo; Kato, Shinsuke; Zeng, Jie

doi:10.1016/s0360-1323(99)00033-5

Cited by 172 publications

(95 citation statements)

References 3 publications

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“…Although these studies lack breathing (inhalation or exhalation), they have identified that torso complexity can influence airflow around the body and, more importantly, within the facial region. Murakami et al (2000) shows that as warm air rises around a human body, the airflow accelerates vertically as it passes from the neck to the head region. Topp et al (2003) illustrates that the presence of legs causes a decrease in velocity at the center of the torso compared to a torso with no legs.…”

Section: Introductionmentioning

confidence: 99%

Uncertainty in Aspiration Efficiency Estimates from Torso Simplifications in Computational Fluid Dynamics Simulations

Anderson

Anthony

2012

The Annals of Occupational Hygiene

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Computational fluid dynamics (CFD) has been used to report particle inhalability in low velocity freestreams, where realistic faces but simplified, truncated, and cylindrical human torsos were used. When compared to wind tunnel velocity studies, the truncated models were found to underestimate the air's upward velocity near the humans, raising questions about aspiration estimation. This work compares aspiration efficiencies for particles ranging from 7 to 116 µm using three torso geometries: (i) a simplified truncated cylinder, (ii) a non-truncated cylinder, and (iii) an anthropometrically realistic humanoid body. The primary aim of this work is to (i) quantify the errors introduced by using a simplified geometry and (ii) determine the required level of detail to adequately represent a human form in CFD studies of aspiration efficiency. Fluid simulations used the standard k-epsilon turbulence models, with freestream velocities at 0.1, 0.2, and 0.4 m s −1 and breathing velocities at 1.81 and 12.11 m s −1 to represent at-rest and heavy breathing rates, respectively. Laminar particle trajectory simulations were used to determine the upstream area, also known as the critical area, where particles would be inhaled. These areas were used to compute aspiration efficiencies for facing the wind. Significant differences were found in both vertical velocity estimates and the location of the critical area between the three models. However, differences in aspiration efficiencies between the three forms were <8.8% over all particle sizes, indicating that there is little difference in aspiration efficiency between torso models.

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Section: Introductionmentioning

confidence: 99%

Uncertainty in Aspiration Efficiency Estimates from Torso Simplifications in Computational Fluid Dynamics Simulations

Anderson

Anthony

2012

The Annals of Occupational Hygiene

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“…Numerical techniques have been successfully used to describe the thermal interaction between the human body and its surrounding environment [1,2,3,4]. However, most of these studies were undertaken with reference to adults whose physical shape, thermo-physiological properties and thermoregulatory processes are different from those of infants [5,6,7].…”

Section: Introductionmentioning

confidence: 99%

A combined study of heat and mass transfer in an infant incubator with an overhead screen

Ginalski

Nowak

Wrobel

2007

Medical Engineering & Physics

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The main objective of this study is to investigate the major physical processes taking place inside an infant incubator, before and after modifications have been made to its interior chamber. The modification involves the addition of an overhead screen to decrease radiation heat losses from the infant placed inside the incubator. The present study investigates the effect of these modifications on the convective heat flux from the infant's body to the surrounding environment inside the incubator. A combined analysis of airflow and heat transfer due to conduction, convection, radiation and evaporation has been performed, in order to calculate the temperature and velocity fields inside the incubator before and after the design modification. Due to the geometrical complexity of the model, Computer-Aided Design (CAD) applications were used to generate a computer-based model. All numerical calculations have been performed using the commercial Computational Fluid Dynamics (CFD) package FLUENT, together with in-house routines used for managing purposes and User-Defined Functions (UDFs) which extend the basic solver capabilities. Numerical calculations have been performed for three different air inlet temperatures: 32, 34 and 36ºC. The study shows a decrease of the radiative and convective heat losses when the overhead screen is present. The results obtained were numerically verified as well as compared with results available in the literature from investigations of dry heat losses from infant manikins.

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“…They reported that a heat release from a human body (in a standing position) to the surrounding environment by convection was 29.14 W/m 2 and the mean value of the convective heat transfer coefficient was 4.95 W/m 2 K. Following the above conclusions and considering the skin surface area of 1.5696 m 2 (Murakami et al 2000), the constant heat flux of 13.26 W/m 2 along the human body's rectangle edges is assumed.…”

Section: Mathematical Model Of Ventilated Zonementioning

confidence: 99%

Indoor Air Quality and Thermal Comfort in Naturally Ventilated Low-Energy Residential Houses

Krzaczek¹,

Tejchman²

2012

Air Quality - Monitoring and Modeling

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Combined simulation of airflow, radiation and moisture transport for heat release from a human body

Cited by 172 publications

References 3 publications

Uncertainty in Aspiration Efficiency Estimates from Torso Simplifications in Computational Fluid Dynamics Simulations

Uncertainty in Aspiration Efficiency Estimates from Torso Simplifications in Computational Fluid Dynamics Simulations

A combined study of heat and mass transfer in an infant incubator with an overhead screen

Indoor Air Quality and Thermal Comfort in Naturally Ventilated Low-Energy Residential Houses

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