Abstract
The effect of the natural ventilation of mines was studied thermo-dynamically and a term, natural ventilation head (NVH), was proposed, which is given by-∅ vdp along a cycle of air current composed of underground air current and atmosphere. The natural ventilation pressure (NVP) is able to be defined in several ways, i.e.by-∅ydz, or by NVH multiplied by air density. The former was denoted NVPγz the latter NVPm or NVPex, according to the air density. Another kind of NVP, NVPapp was proposed, that is obtainable by a graphical determenation. The relation among these was discussed. The method of direct experimental determination of NVP was also studied. The theory above mentioned was proved by experiments carried out at Hashima Coal Mine.
