The Performance Of Flow And Heat Transfer Experiments And Simulation Studies On Granular Flow Spallation Target

The spallation target is an important part of ADS system(accelerator driven subcritical system).By theoretical calculation,granular flow Target is a newly proposed of a high power spallation target.The granular flow target takes advantage of the solid target and the liquid target.It has good corrosion resistance and no hydrodynamics instability of common fluids.The research has tremendous potential.It had great significance to study the design and optimization of flow and heat transfer on internal particles in spallation targets.Based on the small flow circulation system of granular flow,this paper is studied on specific inclination angle of the inclined pipeline by experiment,when 3D granular flow is beginning to translate from jam to dense.It is found that the granular flow could flow out smoothly from the inclined pipeline,when the inclination angle is greater than 22 °.And the effect of granular flow on the transition process of dense flow-sparse flow was further studied.By numerical simulation of geometric model of the target zone,it is found that the flow rate of the dense granular flow in the gravity flow can be estimated by the Beverloo empirical formula in the model of the funnel flow,and the inclination angle of the funnel has a certain influences on the particle's velocity.Aiming at the granular flow heat transfer model applied in ADS spallation target,the flow and heat transfer process of the particles in the plate heat exchanger were analyzed.Based on the numerical simulation,it is found that the manifold of the model inlet has no effect on the mass flow of the funnel model,and its mass flow can be estimated by Beverloo 's empirical formula.Through the simulation of the flow rate and volume fraction in the granular flow,it is found that the flow state of the particles in the plate heat exchanger is dense flow.Based on the understanding of the flow characteristics of the granular flow in the plate heat exchanger,the simulation study is performed for the heat transfer process and heat transfer performance in the heat exchanger.The calculation of the heat transfer in the particle-plate heat exchanger mainly takes into account the heat transfer process between the particles and the wall.The average effective heat transfer coefficient of the granular flow plate heat exchanger is about 81.43 W /(? * K),when the particle velocity is 0.068m/s.The temperature difference between inlet and outlet of the particle phase is about 28 K under constant temperature wall condition.In the model,the radial distribution of the particle phase temperature is related to the position of the channel.The change of the particle phase temperature in the middle position is smaller than that of the two sides in the same height.The axial grain temperature decreases gradually from the inlet to the outlet.To achieve a stable temperature.The simulation also found that the particle temperature difference between the inlet and outlet.is smaller,when the granular flow rate is larger.