experiments on variable-mass threshing of rice in the tangential-longitudinal-flow combine harvester

the existing studies of threshing process of combine harvesters adopt the assumption of constant mass, which is contradictory to the phenomenon of separation of grains and short stalks in actual threshing process. therefore, the characteristics of threshing and separation are not accurately described. aiming at this problem, this study established the tangential-longitudinal threshing and separation test-bed with tangential-flow device, auxiliary feed beater, and longitudinal-flow device of tangential-longitudinal-flow combine harvester and conducted experiments and analysis of rice threshing with feed rates of 5, 6, and 7 kg s-1. the results showed that the changes in rates of material flow along the arc-length of concave in tangential-flow device and longitudinal-flow device were equal to the changes in rates of material density with time. in the process of variable-mass and constant-mass rice threshing, when the feeding rates were 5, 6, and 7 kg s-1 in the test-bed, the flow rates from the tangential-flow device were 4.07, 5.01, and 5.95 kg s-1, respectively. the average power consumption of the tangential-flow drum in variable mass threshing process was higher than that in the constant mass threshing process by 2.16, 2.73, and 3.09kw, respectively. the flow rate at the outlet of the longitudinal-flow device was 3.34, 4.04, and 4.72 kg s-1, respectively. the average power consumption rate of the longitudinal-flow drum in variable mass threshing process was lower than that in the constant mass threshing process by 7.32, 10.44, and 12.17kw, respectively. the results of material flow rate and power consumption would offer the basis for the design of longitudinal-tangential flow threshing and separation device.