Thermo-hydrodynamic behaviors of spiral groove gas face seals are investigated for the cases of low seal pressure.
Pressure and temperature fields of gas film are calculated, and then influence of thermal distortion on seal performance are analyzed. It is found that spiral grooves lead to complex film temperature
distributions and rotational speed results in the increase of whole film temperature. But the shear heat
and pumping effect of spiral grooves have little influence on film temperature gradient along the leakage
direction. The face thermal distortion, forming divergent clearance along the leakage direction, makes
the opening force decrease and the leakage increase. A higher seal pressure and clearance will result in a
larger thermal distortion. And the rotational speed may enhance the face thermal distortion further in
some low pressure cases.