Experimental study on the performance of gas screw seals.

In this study, the experiments for the screw seal having a rectangular screw groove on a shaft are carried out in the range of the peripheral velocity up to 250m/s by using air at a room temperature. The various characteristics of the screw seal with respect to helix angle, groove width ratio, aspect ratio, number of thread etc, are examined in both cases of the stationary and revolutional states. As a result, it is found that the seal performance is evaluated availably by making use of a dimensionless parameter, that is, the cross-sectional area of screw groove divided by square of seal length. And then, the seal performance amounts to maximum when its parameter is nearly equal to 0.1. The effects of helix angle, groove width ratio and number of thread on the performance seems to be not so much important.