To explain the separation phenomena and meet the requirement of the leakage of the non-contact hydrostatic mechanical seal

an active controllable method for mechanical seals based on the change of the closing force was proposed. The principle of the method was developed

including: control strategy

control components and control flow. Taking the shaft mechanical seals in the high-speed turbopump as the object

the design for the controllable seal was carried out

and the influence of the controllability and the control elements on the performance of the seals were obtained by the theoretical and experimental methods. The existing separation speed theory was developed

and with the experiment results

the mechanism of the separation speed for the controllable seal was validated. The results show that the strategy of regulating the closing force could satisfy the leakage of the seal; and the range of the control sensitivity coefficient is[1

3.19]. The developed separation speed theory can reasonably explain the transformation process from the contact state to non-contact state between the mechanical seal faces in the takeoff stage. The results are helpful to design

monitor and control the special mechanical seal under special working conditions.