Numerical Study Of The Effect Of Cavitation On Ventilated Supercavitating Flow

Speed constraints have become a bottleneck affecting the development of conventional weapons.Supercavitation technology isolates the fluid around underwater vehicles from the surface of the vehicle through a gas layer,greatly reducing navigation resistance,and thus increasing the speed of the vehicle.Compared to natural supercavitation,supercavitation generated by installing a cavitation device at the head of the vehicle and assisting in ventilation is more stable.At present,literature research mainly focuses on a single type of cavitation,with limited research on different types of cavitation parameters and multi port flow distribution.This article is based on numerical simulation methods,using the VOF model to couple Schner-Sauer cavitation model and RNG turbulence model,and comparing them with experimental results to verify the rationality of the selected model.Subsequently,the effects of cavitation parameters and ventilation parameters on supercavity morphology and vehicle resistance are studied.The main tasks are as follows:From the perspective of cavitation parameters,research was conducted on the vehicle with disc cavitation,cone cavitation,and jet cavitation.The feasibility of different cavitation geometry and ventilation design schemes was verified,and research was conducted from the aspects of cavitation development and detachment,cavitation size,flow field structure,and vehicle resistance.The detachment of bubbles in different types of cavitation vehicles always starts from the solid wall and develops downstream of the flow,without stable frequency characteristics.The increase in the diameter of the disc cavitation device will lead to an increase in resistance on the vehicle,and the cavitation shape tends to be unstable;The diameter and length of the cavitation bubble increase with the increase of the cavitation cone angle,and the influence of the cavitation cone angle on the length size is more obvious.The total resistance of the navigation body first decreases and then increases;Increasing the length of the jet pipe results in a decrease in the size of the bubble as the length of the jet pipe increases.There is a critical value between the length of the jet pipe and the resistance of the vehicle.When the critical value is exceeded,the resistance of the vehicle increases significantly.From the perspective of ventilation parameters,a study was conducted on a vehicle with disc cavitation,cone cavitation,and jet cavitation.Three different stages of cavitation size variation with airflow were given,namely: slow growth stage,rapid increase stage,and relatively stable stage;The resistance of the disc cavitation body decreases with the increase of ventilation,while the resistance of the cone cavitation body increases with the increase of ventilation.The resistance of the jet cavitation body first decreases and then increases with the increase of ventilation.Explored a rapid optimization scheme for the distribution of ventilation flow rates for three types of cavitation devices.For disc cavitation devices and cone cavitation devices,the scheme of gradually increasing the ventilation rates of the first,second,and third ventilation holes can be selected.For jet cavitation devices,the first ventilation hole should account for about 50% of the total ventilation rate of the navigation body,and the ventilation rate of the second ventilation hole should be slightly less than that of the third ventilation hole.