Contact Surface

This section describes the Contact Surface model.

The passenger is permanently in contact with the vehicle seat. Therefore, it is necessary to divide the skin elements at the contact segments into two different surfaces. This leads to two skin temperatures for a segment:

  • Skin temperature for the surface in contact with the seat
  • Skin temperature for the free surface

The effective temperature at the contact surface is replaced by the temperature of the seat TCONTACT. The dry heat flux is calculated only from heat conduction between the contact surface and the seat. Taking clothing into account, the thermal efficiency factor at the contact surface is given by:

FTEj=αCLOTHjFSURFjαCLOTHj+αCONTACTFSURFj
(62 63)

The dry heat flux then becomes:

Q˙DRYj=αCONTACTFTEjACONTACTj(T4,jTCONTACTj)
(62 63)

The thermal efficiency factor FTE is used to modify all base values. For all further calculations, such as regulation or heat losses, the respective temperatures of the skin elements are used and so two separate values result.