中文摘要：

为降低油菜联合收获过程中的割台损失,针对机械直播和移栽的油菜,该文提出对行操作并使用正压气流田间在线收集处于下落过程中油菜籽粒的方法。利用自行试制的台架试验装置,首先设计正交试验,确定无秸秆正压气流场中影响收集效果的相关影响因素的显著性水平,然后对重要影响因素进行单因素试验,以获得对应的回归方程,为装置结构及工作参数的进一步优化提供预测依据。试验表明,影响收集效果的因素依次为收集单体高度、长度、风机工作电流频率及喷嘴仰角,且前3个因素对收集效果的影响较为显著,而喷嘴仰角对收集效果的影响不显著。4种因素对收集效果的影响趋势均符合二次多项式拟合,且收集效果（籽粒收集量）随收集单体高度、风机工作电流频率及喷嘴仰角的增加而增加,而随收集单体长度的增加而减小,其决定系数分别为0.9773、0.9985、0.9682和0.9686,因此在整机功率分配允许的情况下,应尽可能选用较大功率的风机,并不断优化管道布局、单体及喷嘴的结构形式及参数大小,以保证足够的气流场强度及作用范围,从而起到应有的收集效果。本文研究为后续进一步对有静止秸秆及有运动秸秆室内台架试验和田间试验条件下油菜割台籽粒损失气力式收集装置及试验的研究奠定了基础。

英文摘要：

Due to the oil rape＇s two biological characters of fragility and non-synchronization of maturity, a high loss rate（8%） of rape seeds often appears when this plant is harvested by a combine harvester. The higher the maturity is（often accompanied by a lower moisture content）, the greater the cutting platform loss is in the front part of the machine, and the smaller the loss of the threshing, separating and cleaning in the behind; and vice versa. Insufficient maturity causes low oil rate, while high moisture content will increase difficulty of the threshing, separating and cleaning. Therefore, consideration should be given to both the front and behind loss of the machine while methods and counter-measurements are tried to be found. It means that, while the threshing, separating and cleaning devices are optimized, new types of the cutting platform should be developed at the same time to fit a new harvest time which can be shifted to backwards appropriately or on a sunny afternoon for a higher maturity and lower moisture content. This paper proposed a novel method to collect the falling rape seeds in front of the harvester header by a line-by-line mode with the longitudinal airflow of positive pressure for rape which is mechanically transplanted or sown. Firstly, with a bench trial device, an orthogonal experiment based on the scheme of L9（34） was conducted to determine the significant level of relevant factors impacting on the collection effect of falling rape seeds in field of longitudinal positive pressure airflow without no straw. Then single factor tests for the important factors were implemented to obtain the corresponding regression equation for predicting the collection effect in further optimization of the structure and work parameters of the device. Experiments showed that factors affecting the collection amount of the falling seeds are the height and length of the collection monomer, the operating current frequency of the turbine（which determines the airflow velocity at the front place of th