Simulation And Analysis Of Enhanced Heat Transfer Performance Of Phase Change Microcapsule Suspension Flow In Circular Tube

With the high-speed development of the world,the demand for energy is becoming more and more serious,but is behind high demand brought by the energy over-exploitation and lack of a series of problems,therefore,save energy,energy efficiency,reduce energy loss in the transmission process become scholars and scientists cannot be ignored.Phase change micro-capsule is a kind of core-shell structure.Its application has a great prospect because its internal core material can absorb a large amount of latent heat during phase change,and its heat transfer effect is further improved after it is configured as suspension,and the loss and pump power consumption in the heat transfer process are reduced.In this paper,the flow characteristics and heat transfer characteristics of phase change micro-capsule suspension in a circular tube are analyzed and discussed by CFD technology.By reading literature,is clear about the physical properties of the phase change micro-capsule and its suspension and the heat transfer mechanism,application of CFD technology to simulate the flow field of turbulence model,the numerical calculation model and the clear particles in the flow field and pressure gradient force in the virtual mass force,Saffman force,drag force and gravity on detailed analysis of using two equations model,Simple algorithm,DPM model of phase change micro-capsule suspension flow in the circular tube to carry on the numerical simulation,analysis of the heat transfer characteristics and flow characteristic.Join phase change micro-capsule particle,this paper analyses heat transfer characteristics of fluid,the results show that compared with pure water,phase change micro-capsule particle is added to a fluid in the tube,the tube wall temperature will go down,and with the increase of Re,including the increase of fluid convection heat transfer capability is nonlinear,and the trend of increasing gradually decreases,and until smooth.Under the condition of relatively low Re,the enhanced heat transfer ability of phase change micro-capsule technology is stronger than that of bellows technology,while under the condition of relatively high Re,the enhanced heat transfer ability of bellows technology is stronger than that of phase change micro-capsule technology.This paper respectively to different pipe wall heat flux density and mass fraction and the phase change micro-capsule suspension of different volume flow numerical simulation,the results show that the circular tube wall surface heat flow density is higher,the export of the lower pressure drop,outlet fluid temperature and wall temperature is higher,the local affected by surface heat flux change is not obvious;Phase change micro-capsule suspension mass fraction is higher,the greater the tube side pressure drop,lower tube wall temperature and outlet temperature of the internal fluid,before the end of the phase transformation,phase change micro-capsules to increase the local of the fluid,and with the increase of the suspending liquid mass fraction,the local also will increase,at the end of the phase change,for the low concentration of phase change micro-capsule suspension,its partial as the slurry concentration increases,and when the concentration increases to a certain extent,the local lower than pure water,and decreases with the increase of slurry concentration;In phase change micro-capsule suspending liquid volume flow under the condition of relatively low,the greater the volume flow,its export pressure drop,the greater the fluid temperature,and the exit tube wall temperature is lower,the volume of a phase change micro-capsule suspension in the circular tube flow increases to a certain extent,phase change micro-capsule particle not completely melt flow pipeline,at this time,with the increase of suspending liquid volume flow,the exit temperature difference is reduced,and reduce the trend of more and more gentle,further improve the effect of heat-exchange of the volume flow increase will no longer obvious,the volume flow control in a reasonable range to make better use of the benefits of such phase change latent heat.