Research on Compensation Characteristics of Deep Sea Hydraulic System Considering the Influence of Multiple Parameters

The rolling diaphragm type compensator is the core component of the deep-sea hydraulic system, whose main function is to introduce seawater pressure and compensate for changes in hydraulic oil volume caused by factors such as deep-sea pressure, environmental temperature, and asymmetric actuator volume difference. The compensation characteristics of the compensator determine the depth at which the submersible can descend. Its design has long relied on experience and mainly considered the effect of pressure, ignoring other influencing factors. To solve this problem, this article conducts research on the two key parameters of the rolling diaphragm type compensator, compensation volume and compensation pressure, to optimize the structure of the compensator and improve its performance. Firstly, the existing initial compensation volume solving model was optimized by considering the coupling effect of environmental pressure and temperature. Starting from engineering practice, a compensation volume optimization solving model based on No. 10 aviation hydraulic oil was established. Then, based on the above model, mathematical modeling and simulation were conducted to study the fluctuation of compensation pressure under interference at sea depths of 0 meters, 500 meters, 1000 meters, and 2000 meters. It was found that the fluctuation of compensation pressure was mainly caused by the flow rate of the input/output compensator, and the fluctuation of compensation pressure decreased with the increase of sea depth. Research has shown that the optimized compensation volume solving model can calculate a more accurate initial compensation volume, and measures such as reducing the initial compensation volume, increasing the equivalent force area of the rolling diaphragm, and reducing the stiffness of the compensation spring can reduce the fluctuation of compensation pressure and optimize the performance of the compensation device.