Study On The Movement Behavior Of Granular Matter Under Microgravity

Granular matter can be seen everywhere in our daily life.Most of the matter on the earth is composed of discrete solid matter.With the development of technology and theory,particulate matter is being used in industry,transportation and other fields because of its characteristics.Dense particle flow target is a new concept design of highpower spallation target proposed to meet the needs of ultra-high beam power in ads system.Particle flow spallation target has the advantages of both solid and liquid targets.Particle flow has no hydrodynamic instability of ordinary fluid and also slows down the corrosion effect of target structural materials.It has the potential to carry higher beam power physically.On this basis,it is very necessary to study the particulate matter and particle system,which is very important for the application and optimization of particulate matter in particle flow spallation target.The granular matter has the characteristics of energy dissipation,so it is a system far from equilibrium.We know that an open system far away from the equilibrium state can generate self-organization phenomenon through internal action when the external conditions reach the critical state through a continuous exchange of energy or matter with the outside world so that the system can spontaneously change from the original disordered state to the ordered state in time or space,such as the formation of "clusters".In this paper,based on the granular gas,the phenomenon of clusters in the granular gas system caused by "phase separation" is studied by numerical simulation.In this paper,by using vibration system,the conditions and determination methods of the formation of particle gas clusters,the phase diagram of particle gas;the influence of parameters such as friction coefficient and recovery coefficient of particles on the formation of clusters,the characteristic time of particle system reaching steady-state,the influence of different systems and accumulation fractions on the steady-state of particle system,the influence of boundary effect on clusters is verified in particle system and the degree of particle cluster and the distribution of particle volume fraction in the cluster were studied.The results provide an important reference for future microgravity experiments.We also studied the change of the volume fraction of particles under the condition of microgravity.Through the experiment of particle accumulation under microgravity,we get that the change value of particle accumulation volume fraction is near 0.01 in the process of changing from gravity to zero gravity,and get the minimum accumulation fraction = 0.61 in our experiment,the experiment shows us the direction for our next work and finds out the range of volume fraction change of particle flow under the condition of microgravity.The results provide a reference for the application of granular materials in the spallation target of particle flow.