Research on the energy storage characteristics of diaphragm accumulator

Accumulator is the important energy storage element in hydraulic system. It is very important to study accumulator efficiency for improving the performance of hydraulic system. In this paper, the mathematical model of the diaphragm accumulator hydraulic storage characteristic is established based on its structure feature and working principle. This paper establishes the thermal model, taking the thermal dynamics of air and the heat exchange among the bladder, oil, the shell into consideration; and establishes the fluid dynamical model, taking the fluid characteristic of oil and the influence of valve into consideration. The platform is built and the charge-discharge experiment is conducted in low and high frequency conditions. The pressure and temperature in air chamber and oil chamber is measured to calculate the power loss of thermal cycle and the hydraulic loss in the inlet. The result of the simulation and the experiment shows that: in the low charge-discharge frequency condition, the thermal efficiency and hydraulic efficiency are both more than 90%; in the high charge-discharge frequency condition, the thermal efficiency increases, while with the increase of flow velocity, the hydraulic efficiency sharply decreases due to throttling loss.