Experiments on Variable-mass Threshing of Rice in t he Tangential-longitudinal-flow Combine Harvester

Abstract

The existing studies of threshing process of combin e harvesters adopt the assumption of constant mass, which is contradictory to the phenom enon 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 separatio n test-bed with tangential-flow device, auxiliary feed beater, and longitudinal-flow device of tangential-longitudinal-flow combine harvester and conducted experiments and ana lysis of rice threshing with feed rates of 5, 6, and 7 kg s -1 . The results showed that the changes in rates of m aterial flow along the arc-length of concave in tangential-flow device and longitudinal-flow device were equal to the changes in rates of material dens ity with time. In the process of variable-mass and constant-mass rice threshing, whe n the feeding rates were 5, 6, and 7 kg s -1 in the test-bed, the flow rates from the tangentia l-flow device were 4.07, 5.01, and 5.95 kg s -1 , respectively. The average power consumption of th e tangential-flow drum in variable mass threshing process was higher than tha t 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 k g s -1 , respectively. The average power consumption rate of the longitudinal-flow drum in v ariable mass threshing process was lower than that in the constant mass threshing proc ess 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 flo w threshing and separation device