The Experimental Study Of Density Lock Mechanism

In this dissertation the behavior of fluids stratification in density lock is studied through the method to combine visibility observation with the experimental data analysis. The grid is put into the density lock at experimental research. The influence of various factors on density lock is studied by adjusting disturbance, temperature and changing different start-up modes, then analyzed the mechanism of density lock.The result indicates that: density stratification in density lock formed by hot and cold fluid can prevent heat transfer downward in the vertical channel; stratification can be formed on the occasion of a small disturbance, but it can not be formed when the disturbance surpasses a critical value; the interface will moves downward when temperature difference increases, but the anti-disturbance capacity is enhanced because the gradient of temperature increases; the stratification becomes more stable with the grid; on the occasion of temperature difference forms before the disturbance will make the stratification more stable as well.Besides, the process of stratification is analyzed in the paper. Stratification can be divided into three types, strong stratification, weak stratification and no stratification. Although weak stratification can also prevent heat and mass transfer, it's unstable and easy to be destroyed. The research also indicates that, the oscillation occurs in the grid and when it exceeds the density lock, the stratification will be destroyed.Design method of density lock is proposed on the basis of experimental research and analysis. According to these methods, three schemes of density lock were designed.