[apsumo]

G'day,

I'm currently running a transient simulation to determine the heat transferred from a human body into very slow moving air <1m/s. While I've been able to get some relatively good results in terms of heating the air, the body temperature doesn't change

Is there something amiss with how I've defined the material of the body or boundary conditions? There heat seems to be transfered from the body to the air but there's no change in the body temperature from it's initial condition of 37°C.

[urosgrivc]

If you have set Boundary condition for human surface temperature to 37°C than that is your ansver it canot change If you hawe set it to 37°C.

This is a relatiwely dificult problem (it is posible to make it work quite well) as boundary condition could be set in three ways and it is usualy dependant of the cloathing and action of the human. If the human is doing something than the power output from the human is higher and if he wears a T-shirt it is definitly diferent of if he would wear a thick jacket.

CFX however has a special post feature called something like thermal comfort factor, and is ment to predict how the person perciedes the temperature. To use it ewen radiation has to be included.

There are medical books how to determine how much power a human is puting out determined by all prewiously mentioned factors + the size and weight of the human, when you get the corect number, something in the order of (70-150)W or so maybe more if he is doing real phisical work than this can be your boundary condition.

example below, try searching for simulations that hawe already been made, maybe these can also guide you.
https://www3.nd.edu/~nsl/Lectures/mp...the%20body.pdf

[piu58]

Modelling a human body (or every other animal) with standard boundary condition is not a correct way. The most important effect you cannot take into account is the obstruction or dilation of periphere vessels with temperature, and the transpiration which generates vaporisation cooling.
You need to model the reaction of the organism the brutto external cooling or heating effect, that means including the combined effect of external temperature, air speed and clothing / pelage or plumage.

Not an easy task.