Experiments of dense-phase pneumatic conveying of pulverized coal using nitrogen are carded out in an experimental test facility with the conveying pressure up to 4. 0 MPa and the gas-solid ratio up to 450 kg/m^3. The...Experiments of dense-phase pneumatic conveying of pulverized coal using nitrogen are carded out in an experimental test facility with the conveying pressure up to 4. 0 MPa and the gas-solid ratio up to 450 kg/m^3. The influences of different conveying differential pressures, coal moisture contents, gas volume flow rates and superficial velocities on the solid-gas ratios are investigated. Shannon entropy analysis of pressure fluctuation time series is developed to reveal the flow characteristics. Through investigation of the distribution of the Shannon entropy under different conditions, the flow stability and the evolutional tendency of the Shannon entropy in different regimes and regime transition processes are discovered, and the relationship between the Shannon entropy and the flow regimes is also established. The results indicate that the solid-gas ratio and the Shannon entropy rise with the increase in conveying differential pressure. The solid-gas ratio and the Shannon entropy reveal preferable regularity with gas volume flow rates. The Shannon entropy is different for different flow regimes, and can be used to identify the flow regimes. Both mass flow rate and the Shannon entropy decrease with the increase in moisture contents. The Shannon entropy analysis is a feasible approach for researching the characteristics of flow regimes, flow stability and flow regime transitions in dense-phase pneumatic conveying under high pressure.展开更多
Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery.The dynamic equation of a simply supported wet pipe conveying fluid is presented,taking structural damping...Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery.The dynamic equation of a simply supported wet pipe conveying fluid is presented,taking structural damping of the pipe and viscidity of the fluid into consideration.And the equation is also solved by using Galerkin's method.Modal identifications based on strain gauge test are carried out on both dry pipes(without fluid in it) and wet pipes(pipes conveying fluid).It is concluded from the comparison of the results that both natural frequency and the damping ratio decrease as the pipe filled with fluid,but the mode shapes vary little.Variation of equivalent damping factor is also tested.Experimental results reveal that the equivalent damping factor of fluid and the damping ratio depend greatly on the initial deformation,and fluid induced damping decreases the universal damping ratio of the pipes conveying fluid.展开更多
基金The National Basic Research Program of China(973 Program) (No2004CB217702-01)the Foundation of ExcellentPhDThesis of Southeast University
文摘Experiments of dense-phase pneumatic conveying of pulverized coal using nitrogen are carded out in an experimental test facility with the conveying pressure up to 4. 0 MPa and the gas-solid ratio up to 450 kg/m^3. The influences of different conveying differential pressures, coal moisture contents, gas volume flow rates and superficial velocities on the solid-gas ratios are investigated. Shannon entropy analysis of pressure fluctuation time series is developed to reveal the flow characteristics. Through investigation of the distribution of the Shannon entropy under different conditions, the flow stability and the evolutional tendency of the Shannon entropy in different regimes and regime transition processes are discovered, and the relationship between the Shannon entropy and the flow regimes is also established. The results indicate that the solid-gas ratio and the Shannon entropy rise with the increase in conveying differential pressure. The solid-gas ratio and the Shannon entropy reveal preferable regularity with gas volume flow rates. The Shannon entropy is different for different flow regimes, and can be used to identify the flow regimes. Both mass flow rate and the Shannon entropy decrease with the increase in moisture contents. The Shannon entropy analysis is a feasible approach for researching the characteristics of flow regimes, flow stability and flow regime transitions in dense-phase pneumatic conveying under high pressure.
基金Sponsored by the National Natural Science Foundation of China(Grant No.51179102)
文摘Dynamical performance of pipes conveying fluid on board is of great importance to the reliability of machinery.The dynamic equation of a simply supported wet pipe conveying fluid is presented,taking structural damping of the pipe and viscidity of the fluid into consideration.And the equation is also solved by using Galerkin's method.Modal identifications based on strain gauge test are carried out on both dry pipes(without fluid in it) and wet pipes(pipes conveying fluid).It is concluded from the comparison of the results that both natural frequency and the damping ratio decrease as the pipe filled with fluid,but the mode shapes vary little.Variation of equivalent damping factor is also tested.Experimental results reveal that the equivalent damping factor of fluid and the damping ratio depend greatly on the initial deformation,and fluid induced damping decreases the universal damping ratio of the pipes conveying fluid.
