The numerical investigation of human micro-climate with different human simulators

The development of computational fluid dynamics (CFD) made it possible to simulate the detailed flow field and temperature field within the room. The various studies numerically investigated the flow and temperature field both inside and outside the buildings. When investigating the indoor environment, human is an important factor since it perceives the indoor environment and behaves as a source of heat and contaminant as well. Some studies investigated deeper into humans by developing detailed computer-simulated persons (CSP). However, due to the limitation of computer performance, it is still not always possible to conduct the simulation with detailed CSPs. Therefore, many studies adopted the human simulators with simplified geometry, e.g., cylinder and cuboid. However, it is necessary to understand the effect of the geometrical difference of human simulators on the simulation results. Therefore, CFD analysis with different human simulator geometry is conducted to understand the effect.
A human simulator is located in the middle of a room (3 x 3 x 3 m) with an inlet at a lower level of the room and an outlet at a higher level of the room. The air of 20 ℃ flows into the room via inlet boundary condition with the air velocity of 0.1 m/s. The human simulator geometry is the parameter in this study, and the studied cases are cuboid, simplified CSP, and detailed CSP. The Fanger model is applied for simulating heat generation from human skin surface; therefore, the heat generation rate differs depending on the conditions.
As a result, it was shown that the total heat generation rate and surface temperature of human simulators are almost the same, therefore, since all other walls are insulated, the exhaust air temperature also did not differ depending on the cases. However, there was some difference in the ratio between convective and radiative heat loss through the skin. In addition, although the heat generation rate is almost the same, the flow rate of thermal plume around them differed by 10% depending on the human simulator geometry.