The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the r...The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the resistance and pressure of three typical pneumatic resistances are obtained.Then,the method of static characteristics analysis only considering pneumatic resistances is proposed,the resistance network from gas supply to load is built up,and the mathematical model is derived from the flow rate formulas and flow conservation equations,with the compressibility of high pressure gas and temperature drop during the expansion considered in the model.Finally,the pilot spool displacement of 1.5 mm at an output pressure of 15MPa and the enlarging operating stroke of the pilot spool are taken as optimization targets,and the optimization is carried out based on genetic algorithm and the model mentioned above.The results show that the static characteristics of the EPPRV are significantly improved.The idea of static characteristics analysis and optimization based on pneumatic resistance network is valuable for the design of pneumatic components or system.展开更多
Gate valve has various placements in the practical usages.Due to the effect of gravity,particle trajectories and erosions are distinct between placements.Thus in this study,gas-solid flow properties and erosion in gat...Gate valve has various placements in the practical usages.Due to the effect of gravity,particle trajectories and erosions are distinct between placements.Thus in this study,gas-solid flow properties and erosion in gate valve for horizontal placement and vertical placement are discussed and compared by using Euler-Lagrange simulation method.The structure of a gate valve and a simplified structure are investigated.The simulation procedure is validated in our published paper by comparing with the experiment data of a pipe and an elbow.The results show that for all investigated open degrees and Stokes numbers(St),there are little difference of gas flow properties and flow coefficients between two placements.It is also found that the trajectories of particles for two placements are mostly identical when St << 1,making the erosion independent of placement.With the increase of St,the distinction of trajectories between placements becomes more obvious,leading to an increasing difference of the erosion distributions.Besides,the total erosion ratio of surface T for horizontal placement is two orders of magnitudes larger than that for vertical placement when the particle diameter is 250 μm.展开更多
With the rapid development of circulating fluidized bed(CFB)technology in different fields,the disadvantages of conventional non-mechanical valves are becoming more apparent,and they are not suitable to be used in com...With the rapid development of circulating fluidized bed(CFB)technology in different fields,the disadvantages of conventional non-mechanical valves are becoming more apparent,and they are not suitable to be used in complex CFB systems.In this paper,a novel non-mechanical valve named the jet-control valve is presented which can avoid the fluidization of solid particles.The feasibility and performance characteristics of the new valve are investigated with a cold-model dual CFB.The results show that compared with the conventional non-mechanical valve,the jet-control valve can transfer solid particles steadily over a larger range,prevent artesian flow,and improve the leakage characteristics.The effects of the operating parameters and structural parameters on the minimum aeration velocity,solid flow rate,and maximum solid flow rate are studied.A two-valve model is proposed to explain the transport capacity of the valve for one jet pipe.A semi-theoretical expression is obtained based on the experimental data with a maximum deviation of 30%providing useful guide for scaling-up the design.展开更多
基金Project(50575202) supported by the National Natural Science Foundation of China
文摘The structure and working principle of a self-deigned high pressure electronic pneumatic pressure reducing valve (EPPRV) with slide pilot are introduced.The resistance value formulas and the relationship between the resistance and pressure of three typical pneumatic resistances are obtained.Then,the method of static characteristics analysis only considering pneumatic resistances is proposed,the resistance network from gas supply to load is built up,and the mathematical model is derived from the flow rate formulas and flow conservation equations,with the compressibility of high pressure gas and temperature drop during the expansion considered in the model.Finally,the pilot spool displacement of 1.5 mm at an output pressure of 15MPa and the enlarging operating stroke of the pilot spool are taken as optimization targets,and the optimization is carried out based on genetic algorithm and the model mentioned above.The results show that the static characteristics of the EPPRV are significantly improved.The idea of static characteristics analysis and optimization based on pneumatic resistance network is valuable for the design of pneumatic components or system.
基金supported by National Natural Science Foundation of China(Grant No.21276241)etc
文摘Gate valve has various placements in the practical usages.Due to the effect of gravity,particle trajectories and erosions are distinct between placements.Thus in this study,gas-solid flow properties and erosion in gate valve for horizontal placement and vertical placement are discussed and compared by using Euler-Lagrange simulation method.The structure of a gate valve and a simplified structure are investigated.The simulation procedure is validated in our published paper by comparing with the experiment data of a pipe and an elbow.The results show that for all investigated open degrees and Stokes numbers(St),there are little difference of gas flow properties and flow coefficients between two placements.It is also found that the trajectories of particles for two placements are mostly identical when St << 1,making the erosion independent of placement.With the increase of St,the distinction of trajectories between placements becomes more obvious,leading to an increasing difference of the erosion distributions.Besides,the total erosion ratio of surface T for horizontal placement is two orders of magnitudes larger than that for vertical placement when the particle diameter is 250 μm.
基金supported by the Strategic Priority Research Program of the Chinese Academy of Sciences(Grant No.XDA07010300)
文摘With the rapid development of circulating fluidized bed(CFB)technology in different fields,the disadvantages of conventional non-mechanical valves are becoming more apparent,and they are not suitable to be used in complex CFB systems.In this paper,a novel non-mechanical valve named the jet-control valve is presented which can avoid the fluidization of solid particles.The feasibility and performance characteristics of the new valve are investigated with a cold-model dual CFB.The results show that compared with the conventional non-mechanical valve,the jet-control valve can transfer solid particles steadily over a larger range,prevent artesian flow,and improve the leakage characteristics.The effects of the operating parameters and structural parameters on the minimum aeration velocity,solid flow rate,and maximum solid flow rate are studied.A two-valve model is proposed to explain the transport capacity of the valve for one jet pipe.A semi-theoretical expression is obtained based on the experimental data with a maximum deviation of 30%providing useful guide for scaling-up the design.
