| The cleaning device is an important part of the combine harvester,and the assembly quality will directly affect the performance of the whole machine.The combine harvester generally adopts a wind screen cleaning device,wherein the distribution of the airflow field directly affects the cleaning performance index(loss rate,impurity content,etc.).The assembly quality of the wind turbine plays a vital role in the distribution of the airflow field.Therefore,the assembly quality of the combine harvester fan is an important factor affecting the performance of the combine harvester.At present,most domestic agricultural machinery enterprises lack special technical equipment for the assembly quality inspection of combined harvester fans before leaving the factory.This paper studies the quality inspection technology of combined harvester fan assembly for this situation.The main work done is as follows:(1)The basic structure and working principle of the fan in the combined harvester cleaning device are introduced.Five different fan models of the impeller and volute assembly position are established by Solidworks software(the volute moves 10 mm to the up,down,left and right relative to the impeller).3 different fan angle models(145 °,155 °,165 °),3 different fan installation angles(25 °,30 °,35 °)cleaning chamber model and The model of the whole device is cleaned and meshed in the ICEM software,and numerical simulation and calculation are performed in the Fluent software.The speed field,pressure field and fan outlet speed of the fan were analyzed by CFD-Post software.The simulation results show that when the impeller and the volute of the fan are in the optimal assembly position,the air outlet of the fan is the largest,the airflow is evenly distributed,and the internal airflow field distribution is reasonable;when the blade bending angle is 155°,the airflow field distribution of the fan is reasonable;The optimum installation angle in the cleaning device is 30°.At this time,the distribution of the airflow field in the cleaning chamber is more conducive to achieving a good cleaning effect under the cooperation of the vibrating screen.(2)Established the wind turbine assembly quality test bench,arranged 13 x 5 wind speed measurement points at the fan air outlet,5 kinds of volute clearance(10mm,15 mm,20mm,25 mm,30mm),2 kinds of fan impellers The wind speed value of the fan outlet was measured under the inclined condition of 900 rpm.The change of the air volume of the fan outlet was analyzed at 800 rpm,900 rpm and 1000 rpm.The two-dimensional wind speed was drawn by Matlab software.The potential line diagram and the three-dimensional air outlet wind speed distribution map were analyzed and analyzed.The vibration characteristics of the fan were studied by using the DH5902 system.The test results show that at 900 rpm,the volute clearance is 20 mm,the fan vibration is relatively small,and the air outlet volume is 5.507m3/s.When the fan speed is between 800 rpm and 1000 rpm,the air volume of the fan outlet increases by 16.78% and 11.66% for each 100 rpm increase.(3)The wind speed sensor,vibration sensor,speed sensor,tilt sensor and acquisition card were selected,and the software part of the combined harvester fan assembly quality inspection system based on LabVIEW platform was designed.Through the programming of each module,the system realizes the functions of signal acquisition,data storage,data playback,signal processing,signal analysis,assembly quality judgment,etc.,and can display the measured wind speed value and vibration time domain of the corresponding test position in real time on the front panel of the system.Signal,vibration frequency domain signal,fan speed,fan installation inclination and other information.Through the programming of the rear panel,the above signals are extracted,and compared with the indicators of the fan under standard conditions,and then the assembly quality of the fan is identified and judged.After the design of the fan assembly quality inspection system is completed,the test is verified on the whole machine.The test shows that the fan assembly quality inspection system developed in this paper can achieve the expected target and can effectively judge the assembly quality of the combined harvester fan. |
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