Evaluation of Equivalent Temperature in a Vehicle Cabin with a Numerical Thermal Manikin (Part 2): Evaluation of thermal environment and equivalent temperature in a vehicle cabin 2019-01-0698
In the previous paper (Part1), measurements of equivalent temperature (teq) by a clothed thermal manikin and modeling of the clothed thermal manikin for teq simulation are discussed. In this paper (Part2), the outline of the proposed mesh-free simulation method is described and the comparisons of teq between calculations and measurements under summer cooling with solar radiation and winter heating without solar radiation conditions in the vehicle cabin are discussed. The key factors to evaluate the teq on each body segment of the clothed thermal manikin under cooling and heating conditions are also discussed. In the mesh-free simulation, even if there are a hole or an unnecessary shape on the CAD model, only a group of points whose density is controlled in the simulation area is generated without modifying the CAD model. Therefore, the fluid mesh required by conventional CFD code is not required and the analysis load is greatly reduced. The most advantage point is this mesh-free simulation method satisfies the conservation law like mass, momentum and energy. The cabin thermal environment and the teq of the clothed thermal manikin based on the 3D-laser scanned clothing surface are calculated under cooling with solar radiation and heating without solar radiation conditions. The calculated results are compared with measurements, which shows they reproduce the measurements on the whole. Especially, the calculated teq on each body segment of the clothed thermal manikin meet measurements within 3 degree Celsius, which means this method can evaluate the thermal sensation within 1 point accuracy on the ASHRAE 7-point scale. To evaluate the teq on each body segment accurately, the accuracy of the convective heat transfer on the upper segment of the clothed thermal manikin is significant for the cooling condition, while the accuracy of the radiant heat transfer on the upper segment is significant for the heating condition.