Research And Design Of Dust Suppression System For Rice-wheat Combine Harvester

Rice and wheat are basic food in our country.The annual output of rice is 212 million tons and the annual output of wheat is 131 million tons.The workload of rice and wheat harvesting is huge.96% of wheat and 75% of rice have been mechanized harvest.The rice-wheat combine harvester is a typical representative of harvesting machinery.The research and application of the rice-wheat combine harvester in my country has been relatively early,and a relatively complete technical system has been formed.However,during the operation of the combine harvester,the machine interacts with the harvested crop to generate dust.This is mainly manifested in the cutting and conveying process of the harvester header.This dust affects the health of the operator and causes environmental pollution,which has become one of the sources of air pollution.In response to the above problems,the main work and conclusions of this article are as follows:1)The dust at the operation site of the rice-wheat combine harvester was detected by the dust mass concentration detector,dust composition and particle size analyzer.The regional distribution of dust mass concentration was analyzed,and the factors affecting the dust mass concentration were studied.The dust generation rule at the harvest site was explored.The dust composition and particle size are obtained,which lays the foundation for the design of the dust suppression system.2)Through the analysis of suction pneumatic conveying theory,the relevant working parameters of the dust suppression system are calculated.Study the characteristics of agricultural harvest dust and the principle of dust suppression,refer to the knowledge of environmental engineering,and combine the available layout space of the harvester,carry out the structural design and parameter calculation of the dust suppression box and the dust hood.An airborne dust suppression system for a rice-wheat combine harvester with negative pressure suction and filter cartridge dust removal was built,and a preliminary test system was constructed.3)With the help of simulation software,the airflow field of the dust suppression system was analyzed,and it was found that there was jet flow at the entrance of the dust suppression box,the filter load of the filter cartridge was different,the uniformity of dust suppression box was poor,and the mean square error reached 1.54.By increasing the height of the air-reducing chamber,adding an n-type air duct,a wind baffle and an evenly distributed airflow plate,optimize the internal structure of the dust suppression box.Analyze and compare the airflow field of the optimized dust box,it is found that the jet phenomenon at the inlet is alleviated,the filter load difference of the filter cartridge is reduced,the uniformity and stability of the flow field inside the dust suppression box are improved,and the mean square error after optimization is reduced to 0.89,indicating the optimized dust suppression The performance of the system is significantly improved,which has guiding significance for the design of the dust suppression system.4)The Box-Behnken central combination test method was used to optimize the operating parameters of the harvester dust suppression system.The optimization model of the harvester speed,environmental humidity,and fan speed on the dust suppression efficiency of the header and tail was established,and the optimal parameter combination was obtained: harvester speed is 3.7 km/h,fan speed is 3507 r/min,and ambient humidity is 56%.At this time,the efficiency of the header dust suppression is 75.2%,the error from the predicted value is 1.6%;the tail dust suppression efficiency is 77.4%,the error from the predicted value is 2.2%.The dust suppression efficiency after optimizing the operating parameters is significantly improved.Through the Optimization module of Design-Expert8.0.6.1 software,the minimum fan speed is calculated under difficult working conditions,and the minimum fan speed that meets the dust suppression requirements is 3332 r/min.This paper draws on foreign agricultural harvest dust research,absorbs dust suppression principles in other domestic industries,starts with the characteristics of agricultural harvest dust,built an airborne dust suppression system for rice-wheat combine harvester.Analyzes the characteristics of the flow field of the dust suppression box and optimize the internal structure of the dust suppression box.Conduct field efficiency tests on the dust suppression system to obtain the optimal operating parameters of the system.Improve harvester technology and explore the technical ways of dust reduction for combine harvesters.