Parameters Optimization And Tests Of Threshing And Separation Device In Oblique Tangential-longitudinal Combine

With the vigorously promotion of super hybrid rice, qualities of rice field production mechanization is getting even higher. Under the precondition of keeping good work performance of combine harvester, a new generation of combines is increasingly developing to large feeding rate and high efficiency. The aim of this thesis is to accomplish large feeding rate, high efficiency, lower losses and material smooth transportation of oblique tangential-longitudinal combine as well as strengthens the spiral transition device in air assisted feeding. Optimal design of threshing and separation device in oblique tangential-longitudinal combine is conducted through numerical simulation and experimental study methods. The research includes the following aspects:1、Numerical simulation based on air in threshing separation space. Based on the theoretical analysis, we explore the possibility of material in threshing separation space considered as continuous medium. Based on some assumptions, the numerical simulation for the inner flow field of oblique tangential-longitudinal combine is conducted. By the detail analysis and contrast to wind velocity flow field, amount of wind with each inlet and outlet, we can summarize that the performance of spiral feeding system with two spiral blades is best. We further analyzed of the impact of parameter changes gap of the conical spiral transition and cover on internal flow filed.2、Parameters optimization design on threshing and separation device in oblique tangential-longitudinal combine. Based on the results of numerical simulation, in order to improve feeding rate, threshing separation efficiency and reduce threshing and separating loss rate and total power consumption, the structure of oblique tangential-longitudinal combine is determined. Based on the power transmission system, the load test system is constructed.3、Experimental research on the wind speed of the air inlet of the spiral feeding system. To analyze the collected data, we can measure it according to the different sizes of the flow guide cover, and the wind speed measurement is carried out on the 3×7 measuring points of the air inlet of each group by the wind speed instrument. By using Origin software, the wind velocity distribution cloud pictures of each air inlet were obtained, and the air flow rate and average wind velocity of each air inlet were calculated. Summing up the spiral feeding head with flow guide cover, and the radial gap between the 30mm-50 mm, the spiral feeding system can transport 0.5m3/s wind amount.4、Threshing and separating performance test and analysis of the combine. The comparison test using three different structure models of tangential concave was respectively carried out to analysis separation rate of tangential flow drum, impurity rate and total loss rate. Under the result of comparison test, orthogonal experiment was carried out using rotational speed of tangential drum and longitudinal drum, structure form of the tangential drum concave, gap of the conical spiral transition and cover as test factors. By using variance analysis, the preferred operating parameters and structure parameters were obtained. The rotational speed of tangential drum and longitudinal drum is 862r/ min and 806r/ min.The structure form of the tangential drum concave is the type of orientation and separation of hole. The gap of the conical spiral transition and cover is 50 mm. Under optimal parameters, the field experiment results are threshing and separating loss rate of 0.62%, total power consumption of 40.42 k W.