Development of an ultra-high-pressure rotary combined dynamic seal and experimental study on its sealing performance in deep energy mining conditions

With the continuous development of deep oil and gas,minerals,geothermal resources,and other resources,there are increasingly more stringent requirements for equipment.In particular,the ultra-highpressure dynamic seals of deep mining device need to be developed.Therefore,considering the use of dynamic seals in unique deep mining environments,an ultra-high-pressure rotating combined dynamic seal was designed and developed and its sealing performance was experimentally measured and analyzed.The results show that the experimental device can operate stably under a pressure of up to150 MPa and a rotating speed of 76 r/min,and can also operate normally under a rotating speed of up to 140 r/min and a sealing pressure of 120 MPa.During the operation of the ultra-high-pressure rotating combined dynamic seal,the sealing ring does not show obvious damage,which vouches for its sealing performance.No leakage of flow and pressure was detected in the all seal structures within the sealing pressure range of 0-150 MPa.Therefore,the dynamic sealing performance of the device is intact under ultra-high-pressure conditions and can be applied in deep mining environments at a certain depth.The research and development of this device can aid future deep energy exploration and exploitation.

Magnetic nanoparticles and concentrated magnetic nanofluids:Synthesis,properties and some applications

This paper reviews some recent results concerning chemical synthesis of magnetic nanoparticles and preparation of various types of magnetic nanofluids. Structural properties and behaviour in external magnetic field of magnetic nanofluids will be emphasized with relation to their use in leakage-free rotating seals and in biomedical applications.

Design and friction loss study of full-ocean depth oil-filled direct current motor

In this study,we designed an oil-filled motor that can be used at full-ocean depths,and investigated the friction losses caused by the rotating seal and the properties of the oil.The direct current(DC)motor is encapsulated in an aluminum alloy housing.A rubber diaphragm is used to balance the internal and external pressures so that the motor can work on the seabed without pressure difference.To study the resistance caused by the rotating seal,a numerical model of the Glyd ring and the rotating shaft was established.Results from a rotational torque test agreed with those from numerical analysis.The kinematic viscosity of four oils was measured at 1-25℃.Oil bath experiments in an incubator showed that the resistance from oil is highly correlated with its dynamic viscosity.Dimethicone appears to be very suitable as an insulating oil for these motors.The working characteristics of the motor were tested in a high-pressure chamber.The results showed that the motor needs to overcome higher oil resistance under higher pressure.A prototype of a pressure-adaptive motor was designed and applied successfully in the hadal zone at a water depth of more than 10000 m.