Cross-flow fan on multi-dimensional airflow field of air screen cleaning system for rice grain

Abstract

With the advancement of agricultural mechanization and the development of combine harvesters, cleaning devices play a very important role in the grain harvesting process. In this study, the DFPF-25 type material floating velocity measuring device was used to measure the suspension velocity of each component of the grain material. Secondly, the DFQX-3 cleaning device was used to conduct the airflow field test, then the fluid simulation of the cleaning shoe was carried out. The results showed that the simulation and experimental results were in a good agreement under the conditions of single fan and double fan. The high-speed flow velocity formed by the double fan system at the tail of the cleaning shoe was 4.76 m/s (simulation) and 4.03 m/s (experiment), which had outstanding cleaning effects on unfilled grains, long stems, and short stems. To sum up, the installation of the cross-flow fan at the rear of the cleaning shoe has a positive effect on the cleaning effect of the combine harvester, and the double-fan cleaning structure composed of the cross-flow fan and the centrifugal fan can significantly improve the cleaning effect.

A Tiny Object Detection Approach for Maize Cleaning Operations

“…The mAR was twice the mean value of the areas under the curves in the Recall-IoU Graph corresponding to each object category. Similar to AP s , AR s could be defined as the AR for objects with sizes less than 64 2 . Basic-ResNet101 and Basic-EfficientNetB7 represented replacing the backbone of the classic work Faster R-CNN with ResNet101 and EfficientNetB7, respectively.…”

“…Specifically, the convolution kernel and sliding window with the size of 3*3 were employed to sequentially traverse each position of the cross-stage integrated feature, thereby obtaining the intermediate layer (in the same size and dimension as the cross-stage integrated feature) and generating initial anchor boxes in the meantime [54]. In order to more completely and accurately cover the various objects in the impurity-containing maize images, the aspect ratios were set to 1:1, 1:2 and 2:1, as shown in Figure 5, and the area scales were 64 2 , 128 2 and 256 2 , which could correspondingly generate about 50K (75*75*9) anchor boxes on each original image [55]. These were determined by conducting experiments on different categories of target contours in the impurity-containing maize images.…”

“…The performance of the cleaning system is of paramount importance, as it is a critical step in combined harvesting. It exerts a direct influence on the loss rate and impurity content of grain kernels, while also playing a vital role in ensuring efficient drying, qualityguaranteed transportation and safe storage of the harvested grains [1,2]. The cleaning principles are often based on the significant differences in shape, specific gravity, volume and density, etc.…”

Evaluation of the operation of the fan of the combine harvester air-and-screen cleaning system when using an asynchronous electric motor as a drive

“…It differs significantly for impurities and grains. So for soybean grain it ranges between 17.3 and 20.2 m/s, for wheat grain -8.9 and 11.5 m/s, for straw -2.9 and 9.0 m/s, for chaff -2.7 and 5.3 m/s [6,11,13,14,15,16].…”

Establishment of a Feeding Rate Prediction Model for Combine Harvesters

“…Their pivotal role in crop production is indisputable, significantly elevating agricultural productivity. Research indicates that feed rates exert a profound influence on harvesting performance, underscoring the importance of the timely adjustment of pertinent parameters to optimize efficiency [3,4], and feeding rates also serve as one of the important reference parameters for designing crucial working components of combine harvesters, including threshing rotors, cleaning devices, and grain conveying systems [5]. Nonetheless, variations in crop height, density, and forward speed can induce fluctuations in feeding rates to some extent, consequently affecting the vibration characteristics of these components [6].…”