Numerical Simulation of Radiation Heat Transfer of the Human Body for Determining Its Radiation Coefficient

Abstract

Radiation heat transfer coefficient of the human body is one of the most important factors in the field of human skin health. In this paper, the radiation coefficient of the body is calculated by considering external heat radiation of body with the infinite surrounding. At first a human body is designed, and then analysis is done on it. Two segments are assumed for human body (standing and supine). In these segments hands and feet are supposed to be totally open and stretched. In standing segment, soles and in supine segment, the entire back of the body are in contact with the ground and so don’t have heat transfer. The calculation of the results is done by weighted area average method. Radiation coefficient and radiation heat flux are calculated in various emissivity. Because of existence of air around the body in reality, the convection heat transfer is also assumed for human body. Finally two formulas are reported for these segments.

Determination of Radiation Coefficient of Standing Human Body Model by Numerical Approach

“…By using Fluent and applying weighted average method the unknowns are determined. Table 2 shows the radiation coefficients which are reported in Najjaran et al (2011). It can obviously be seen that the coefficients are a bit less than those which are obtained in this work in temperature difference of 15 K. The standing human body model is studied in 36 different cases.…”

“…shows a sample of domain around body model. As mentioned before in Najjaran et al (2011) because of temperature differences between body and surrounding, some heat is supposed to transfer to environment in convectional form. This heat causes the temperature gradient in surrounding air and this gradient leads to density gradient.…”

“…In Najjaran et al (2011) the calculations of radiation coefficient are done with the assumption that the model body is exposed to radiation and convection heat simultaneously. They do this by comparing the effect of radiation and convection.…”

“…Considering the existence of buoyancy force, the surrounding fluid flows. But as the convection is irrelevant to radiation and existence of it around the body conjugates the problem and leads to generating errors; so in this paper the convectional heat is neglected and the calculations are based on the radiation heat rad q ′ ′ and not total heat against Najjaran et al (2011). By using Fluent and applying weighted average method the unknowns are determined.…”

“…Radiation coefficients and radiation heat fluxes related to emissivity and temperature differences for standing human body modelTable 2Radiation coefficients and radiation heat fluxes related to emissivity and temperature differences for standing human body model reported inNajjaran et al (2011) …”