Numerical study of the gas diffusion process between clustered bubbles and technical fluids
The paper presents the results of numerical simulation of diffusion processes taking place between the air bubbles in a cluster and the surrounding fluids (fuel) under periodic external actions in order to develop a mechanism for fuel pre-cleaning from air. Calculations were carried out for different fuel brands in a wide range of system parameters (external field amplitude, initial bubble radius, fuel temperature, etc.). The comparison of bubbles in water and in fuel showed the importance of accounting for physical properties of the fluids in the mathematical model, since they significantly affect the behaviour of gas bubbles. It was found that under fuel ultrasonic processing the establishing step of a stable diffusion cluster will take little time in comparison with the subsequent step of bubble emersion on to the surface. It was established that during the fuel cleaning from air it is preferable to treat such fuel that has high temperature under high pressure, since this leads to the fastest formation of a maximum-sized diffusion stable cluster. The results of this paper are supposed to be further used in the development of a mechanism of the ultrasonic fuel cleaning from air needed at the preliminary step of preparing the fuel for the use in different technological systems operated primarily under extreme conditions.