Hello all;
I am conducting a CFD analysis to examine the temperature variations on the surface of people sitting in an office environment under various inlet air velocity. I defined the surface boundary condition as wall and set the heat flux to 60 W/m². I also enabled the radiation feature (Discrete Ordinates) and set the internal emissivity value to 0.98 for the surface. Turbulence model;k-epsilon and I aplied also wall boundary layer.
First, I solved the analysis using the SIMPLE-C algorithm with first-order for approximately 500 iterations. Then, I stopped it and switched to the Coupled algorithm and second order, solving for an additional 1500 iterations. However, despite having a good mesh quality and cell numbers, no matter what I do, the surface temperature does not decrease below 45-50°C. Where might I be making a mistake?Could you please help?
Have a nice day
The surface heat flux looks to be high. Generally total heat loss from a sitting human being is of the order of 60 W, as claimed by airconditioning books. THe surface area of a complete adult body is of the order of 1.9 m2. So you may check the heat flux boundary condition.
In addition the heat output is when the outside temperature is less than the body temperature.
Good day, Bedri̇ Bi̇çer !
In my opinion, the emissivity coefficient of the skin seems too high. It can range from 0.8 to 0.98, depending on humidity, pigmentation, and age-related changes in the skin. Here is an article regarding the influence of humidity on the emissivity coefficient of the skin: Conference Paper Computational method for estimating the emissivity of human ...
Additionally, the heat flux from a human body varies depending on activity levels, ranging from 45 to 110 W/m² in an office setting. Here is an article on this topic: Article Predicting Energy Requirement for Cooling the Building Using...
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