A numerical investigation of the influence of wind on convective heat transfer from the human body in a ventilated room

As an important factor in indoor human thermal comfort, the wind is investigated in the present study using a fully validated human body-environment interface model based on CFD technology. The three parameters of air speed (v(a), 0.5-2 m/s), turbulence intensity (TI, 5%-40%) and wind direction (0 degrees-180 degrees) were simulated to study their influence on the convective heat transfer coefficient (h(c)) at the surface of the human body. It was found that v(a) influenced the value of h(c) more than TI. The influence of TI on h(c) reached a steady level when v(a) was above 1.5 m/s; for example the greatest rate of change of h(c) at the head remained at 52% as the TI was increased from 5% to 40%. The wind direction had a noticeable influence on the overall h(c) when the v(a) was above 0.5 m/s. A 90 degrees wind (i.e. from the right side) gave a value of hc that was about 20% lower than wind from other directions, and led to an asymmetrical distribution of h(c) over the body surface. Locally, the wind direction did not influence h(c) at the head and feet, and influenced the central segments more than the limbs. Two regression equations for the correlations between h(c) and v(a), TI and wind direction were also generated and validated for continuous evaluation of h(c). The resulting database of values for h(c) can be used in combination with the human thermoregulation models for thermal response prediction in built spaces with increased air speed.