Experimental Study On Open Compression Of Straw-Potato Residue Mixture

In order to obtain the mechanical rheological characteristics of the mixture of corn straw and potato residue in the open compression process,optimize the pellet forming process and improve the forming quality.A universal testing machine and a self-control open compression device were used to the open compression of straw-potato residue mixture,and the stages of open compression curve were divided and the corresponding mechanical rheological model was established.The effects of different test conditions on the mechanical rheological parameters,forming quality and energy consumption of straw-potato residue mixture were investigated by single-factor test analysis,discrete element simulation analysis and parameter optimization test analysis with temperature,mass ratio,feeding amount,particle size,ratio of length and diameter of the die and split taper of the die as the test factors,relaxation ratio and specific energy consumption as the indexes,and the effects of different test conditions on the mechanical rheological parameters,forming quality and energy consumption of straw-potato residue mixture were obtained under the open compression conditions.The best combination of forming process parameters for corn straw and potato residue mixture pellets under open compression conditions was obtained.The main research contents are as follows:1.Through single-factor test research,the stress-time curves of corn straw and potato residue mixture under open compression conditions were obtained,which were divided into compression stage,pushing stage and stress relaxation stage,in which the compression stage was divided into three intervals: loosening,transition and compaction.The stress-strain model and stress-relaxation model of the open compression process were established,and the effects of temperature,mass ratio,feeding amount,particle size,ratio of length and diameter of the die and split taper of the die on the rheological parameters and test indexes of open compression mechanics were analyzed.2.Based on the review and determination of relevant physical parameters of straw and potato residue paricle,contact model analysis was conducted and discrete element simulation model was established;the significant factors were screened by Plackett-Burman test and response surface analysis,the significance level was determined,the model validation and discrete element simulation analysis of open compression forming process were completed,and the force transfer in open compression process was analyzed by force chain evolution.Finally,the energy consumption of forming under different ratio of length and diameter of the die was obtained in the simulation environment,and a better ratio of length and diameter of the die range was determined.3.Through the parameter optimization test,the influence of each test factor on the relaxation ratio and specific energy consumption was analyzed,and a correlation regression model was established to obtain the following order of significance of each factor on the relaxation ratio: temperature > mass ratio > ratio of length and diameter of the die > particle size > feeding amount;the order of significance of each factor on the specific energy consumption was: mass ratio > ratio of length and diameter of the die > feeding amount > temperature > particle size;the best combination of process parameters was obtained by interaction analysis: temperature of 110℃,mass ratio of 1:4,mold hole aspect ratio of 6.2,particle size of 1～2mm,and feeding amount of 16 g.