This study investigates the impact of mixing 0–1 mm fine coal with 0.15–0.3 mm magnetite powder to form a binary dense medium.The aim is to examine how the 0–1 mm fine coal influences the stability of vibration sep...This study investigates the impact of mixing 0–1 mm fine coal with 0.15–0.3 mm magnetite powder to form a binary dense medium.The aim is to examine how the 0–1 mm fine coal influences the stability of vibration separation in a fluidized bed and to achieve steady-state control of vibration fluidization.The vibration segregation behaviour of the binary dense medium under varying fine coal contents is analyzed in this work.The study discovers that the primary contributor to segregation is coal particles smaller than 0.5 mm.As the proportion of fine coal increases,upward movement becomes more pronounced,especially for particles smaller than 0.15 mm,where the upward segregation is most noticeable,with a peak mixing index of 8.06.The study confirms that the larger the particle size of fine coal,the higher the content limit for mixing with magnetite powder.According to studies on the process of fine coal segregation,coal particles larger than 0.5 mm move with the magnetite powder,and the mixing index remains below 3.Coal particles smaller than 0.5 mm fine coal will separate at a uniform speed in a stable environment produced by low vibration energy,with the top-level mixing index remaining constant at 26 after 6 min.Additionally,the study also examines how the fluidization of vibration separation is influenced by the segregation of 0–1 mm fine coal.The evidence shows that longitudinal density segregation within the binary dense medium competes with instantaneous density fluctuation.The longitudinal density distribution of the binary dense medium was found to be nearly uniform when the frequency was set to 25 Hz,amplitude to 2 mm,and upward gas velocity to 1.4 times the minimum fluidization velocity.The density fluctuation was found to be between 0 and 0.1 g/cm^(3).The best separation effect was achieved with fine coal particles ranging from 6 to 1 mm in size under these conditions.展开更多
A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonance...A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.展开更多
In order to solve the problems of unclear film separation in traditional topsoil residual film recovery machine and secondary broken film caused by the toot-shaped structure,a film-soil conveying and vibration separat...In order to solve the problems of unclear film separation in traditional topsoil residual film recovery machine and secondary broken film caused by the toot-shaped structure,a film-soil conveying and vibration separation device was designed.It mainly consists of a first-level vibration conveying chain,roller extrusion and crushing mechanism and secondary conveyor chain,which can complete the functions of conveying,vibration separation,and crushing separation of film-soil composite.Firstly,the mechanical model of the transport process of the film-soil composite was established,and the transport stability of the film-soil composite was analyzed.The vibration characteristics of the vibration mechanism were analyzed by analytical method,and the vibration model of the vibration mechanism was established.The distribution state of residual film-soil mixture was observed and measured by high-speed camera,and the influence of vibration wheel speed and installation distance on the distribution height of residual film-soil mixture was found out.The crushing mechanism of the residual film-soil composite was proved by studying the roller extrusion and crushing mechanism.The Box-Behnken response surface test method was used to carry out field tests on the transport and vibration separation device of film-soil with soil content rate and film leakage rate as evaluation indices.The results indicated that the influencing factors on the soil content rate in a dscending order are conveyor chain speed,vibration wheel speed,and installation distance.In contrast,the factors affecting the film leakage rate,also ranked from largest to smallest,are conveyor chain speed,installation distance,and vibration wheel speed.The combination of film-soil separation parameters is as follows:conveying chain speed is 1.6 km/h,vibration wheel speed is 189.7 r/min,installation distance is 769.7 mm,at this time the soil content rate is 18.31%,and the film leakage rate is 9.49%,which meet the requirements of the recovery of residual film in the plough layer.The conveying and vibration model established in this study can provide a theoretical basis and technical reference for elucidating the soil-film separation process.展开更多
基金This work was supported by the National Natural Science Foundation of China(grant Nos.52474306,52220105008,52125403,52304306)Jiangsu Provincial Natural Science Foundation(grant No.BK20231073)Graduate Innovation Program Project of China University of Mining and Technology(grant No.2024WLJCRCZL100).
文摘This study investigates the impact of mixing 0–1 mm fine coal with 0.15–0.3 mm magnetite powder to form a binary dense medium.The aim is to examine how the 0–1 mm fine coal influences the stability of vibration separation in a fluidized bed and to achieve steady-state control of vibration fluidization.The vibration segregation behaviour of the binary dense medium under varying fine coal contents is analyzed in this work.The study discovers that the primary contributor to segregation is coal particles smaller than 0.5 mm.As the proportion of fine coal increases,upward movement becomes more pronounced,especially for particles smaller than 0.15 mm,where the upward segregation is most noticeable,with a peak mixing index of 8.06.The study confirms that the larger the particle size of fine coal,the higher the content limit for mixing with magnetite powder.According to studies on the process of fine coal segregation,coal particles larger than 0.5 mm move with the magnetite powder,and the mixing index remains below 3.Coal particles smaller than 0.5 mm fine coal will separate at a uniform speed in a stable environment produced by low vibration energy,with the top-level mixing index remaining constant at 26 after 6 min.Additionally,the study also examines how the fluidization of vibration separation is influenced by the segregation of 0–1 mm fine coal.The evidence shows that longitudinal density segregation within the binary dense medium competes with instantaneous density fluctuation.The longitudinal density distribution of the binary dense medium was found to be nearly uniform when the frequency was set to 25 Hz,amplitude to 2 mm,and upward gas velocity to 1.4 times the minimum fluidization velocity.The density fluctuation was found to be between 0 and 0.1 g/cm^(3).The best separation effect was achieved with fine coal particles ranging from 6 to 1 mm in size under these conditions.
基金This project is supported by Commission of Science Technology and Industry for National Defense, China.
文摘A newly designed pneumatic spring with two separate chambers is promoted and double-loop active control is introduced to overcome the following drawbacks of passive pneumatic isolation： ① The low frequency resonances introduced into the system; ② Conflict between lower isolation frequency and stiffness high enough to limit quasi-static stroke;③ Inconsistent isolation level with different force load. The design of two separate chambers is for the purpose of tuning support frequency and force independently and each chamber is controlled by a different valve. The inner one of double-loop structure is pressure control, and in order to obtain good performance, nonlinearities compensation and motion flow rate compensation （MFRC） are added besides the basic cascade compensation, and the influence of tube length is studied. The outer loop has two functions： one is to eliminate the resonance caused by isolation support and to broaden the isolation frequency band by payload velocity feedback and base velocity feed forward, and the other is to tune support force and support stiffness simultaneously and independently, which means the support force will have no effect on support stiffness. Theoretical analysis and experiment results show that the three drawbacks are overcome simultaneously.
基金supported by the Science and Technology Innovation Leading Talent Project(Grant No.2024TSYCLJ0014)the Xinjiang Agricultural Machinery R&D Manufacturing Promotion and Autonomous Region Graduate Research Innovation Project(Grant No.XJ2024G103)the Xinjiang Uygur Autonomous Region“Unveiling and Leading”Project“High-Quality and High-Efficiency Mechanized Recovery Technology R&D and Equipment Application for Farmland Plastic Film Residue”,and the Xinjiang Uygur Autonomous Region“Unveiling and Leading”Project(Grant No.XJJBGS-MG202403).
文摘In order to solve the problems of unclear film separation in traditional topsoil residual film recovery machine and secondary broken film caused by the toot-shaped structure,a film-soil conveying and vibration separation device was designed.It mainly consists of a first-level vibration conveying chain,roller extrusion and crushing mechanism and secondary conveyor chain,which can complete the functions of conveying,vibration separation,and crushing separation of film-soil composite.Firstly,the mechanical model of the transport process of the film-soil composite was established,and the transport stability of the film-soil composite was analyzed.The vibration characteristics of the vibration mechanism were analyzed by analytical method,and the vibration model of the vibration mechanism was established.The distribution state of residual film-soil mixture was observed and measured by high-speed camera,and the influence of vibration wheel speed and installation distance on the distribution height of residual film-soil mixture was found out.The crushing mechanism of the residual film-soil composite was proved by studying the roller extrusion and crushing mechanism.The Box-Behnken response surface test method was used to carry out field tests on the transport and vibration separation device of film-soil with soil content rate and film leakage rate as evaluation indices.The results indicated that the influencing factors on the soil content rate in a dscending order are conveyor chain speed,vibration wheel speed,and installation distance.In contrast,the factors affecting the film leakage rate,also ranked from largest to smallest,are conveyor chain speed,installation distance,and vibration wheel speed.The combination of film-soil separation parameters is as follows:conveying chain speed is 1.6 km/h,vibration wheel speed is 189.7 r/min,installation distance is 769.7 mm,at this time the soil content rate is 18.31%,and the film leakage rate is 9.49%,which meet the requirements of the recovery of residual film in the plough layer.The conveying and vibration model established in this study can provide a theoretical basis and technical reference for elucidating the soil-film separation process.
