Design and Experiment of a Positive–Negative-Pressure-Pneumatic–Vibrating-Screen Coupled Peanut Cleaning Device

Due to the complex physical properties of peanut threshed materials, existing cleaning equipment faces problems such as poor parameter adaptability, low separation accuracy for irregular impurities, and a prominent trade-off between cleaning efficiency and loss, which constrain the industrial application of peanut pickup combine harvesters. In this study, to address these issues, we designed a cleaning device that couples a positive–negative-pressure dual-airflow system with a vibrating screen, and conducted theoretical analysis and parameter design of its key components. Based on gas–solid two-phase flow theory, a numerical simulation model of the coupled positive–negative-pressure dual-airflow system and vibrating screen cleaning device was developed using the CFD–DEM coupling method. With the vibrating-screen vibration frequency, crossflow fan rotational speed, and impurity-suction fan rotational speed as experimental factors, response surface optimization of cleaning performance was carried out. Through multi-response optimization analysis in Design-Expert 13 software, the optimized parameter combination was determined after engineering rounding as follows: crossflow fan rotational speed of 2104 r/min, vibrating-screen vibration frequency of 6 Hz, and impurity-suction fan rotational speed of 1824 r/min. The experimental results showed that under these parameters, the actual impurity content rate of the prototype was 2.06% and the loss rate was 2.33%, and the regression model demonstrated high prediction accuracy and engineering reliability. This study reveals the cleaning and separation mechanism of peanut threshed materials under the coupled action of the vibrating screen and dual-airflow system, providing a theoretical basis for the parameter design and regulation of cleaning devices in peanut pickup combine harvesters.