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不同填充顆粒半徑水稻種子離散元模型參數(shù)標定
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國家重點研發(fā)計劃項目(2017YFD0700701)、山東省重大科技創(chuàng)新工程項目(2019JZZY020622)、國家自然科學基金項目(51505243)和山東省農(nóng)業(yè)科學院農(nóng)業(yè)科技創(chuàng)新工程項目(CXGC2018E18)


Parameter Calibration and Experiment of Rice Seeds Discrete Element Model with Different Filling Particle Radius
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    氣固兩相流耦合仿真被廣泛運用在氣力式排種器工作過程的研究中,因確定性顆粒軌道數(shù)值計算模型的需求,種子多采用顆粒聚合的方法建模,該方法采用的填充球顆粒半徑越小、數(shù)量越多就越能接近種子的真實形態(tài),但會造成仿真計算資源過度消耗、仿真時間增長。為研究不同填充球半徑的水稻種子模型對顆粒間的動力學響應特性的影響,尋找種子模型最佳的填充球顆粒數(shù)量,本文以水稻種子為研究對象,借助三維掃描與逆向擬合的方法獲取種子外形輪廓,分別采用不同半徑(0.30、0.21、0.18、0.16、0.15mm)的球顆粒對其進行填充,形成氣固耦合的水稻顆粒粘結(jié)聚合模型。采用無底圓筒提升、滑落堆積的真實試驗與仿真測定,采用曲面響應法,以休止角為指標,標定出不同填充球顆粒半徑種子模型的種間靜摩擦因數(shù)和動摩擦因數(shù);通過圓筒提升和滑落堆積試驗對參數(shù)進行驗證,以仿真試驗休止角的變異系數(shù)為指標,結(jié)果表明隨著填充球半徑的減小,仿真結(jié)果越接近真實值;通過水稻正壓式排種器氣固兩相流耦合仿真進行驗證,以充種率為指標,結(jié)果表明填充顆粒半徑為0.21mm,仿真時長與仿真精度最優(yōu)。

    Abstract:

    The coupled simulation of gas-solid two-phase flow was widely used in the study of the working process of pneumatic seed metering devices, the seed model was mostly modeled by particle aggregation formed through particle aggregation without overlapping. The simulation seed model would be closer to the real shape of the seed with smaller radius and larger number of filled spherical particles by this method. But the simulation computing resources would be overconsumed and the simulation time would be increased as the method was used. The rice seeds were taken as research object in order to study the effect of rice seed models with different filling sphere radii on the dynamic response characteristics between particles and find the optimal number of filled balls for the seed model. The bonding aggregation model of rice particles for gas-solid coupling was formed by filling with spherical particles of different radii (0.30mm, 0.21mm, 0.18mm, 0.16mm and 0.15mm) after the shape of the seed was got with the aid of 3D scanning and inverse fitting method. The static friction coefficient and dynamic friction coefficient of seed model filled with balls of different radii were calibrated by lifting with bottomless cylinder,sliding accumulation between real test and simulation, using the curve surface correspondence method and the index was the angle of repose. The results showed that the simulation time and simulation accuracy were the best when the filled particle radius was 0.21mm verified by the gas-solid two-phase flow coupling simulation test of the rice seed metering device with positive pressure as the indicator was seed filling rate.

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張榮芳,焦偉,周紀磊,祁兵,劉虎,夏倩倩.不同填充顆粒半徑水稻種子離散元模型參數(shù)標定[J].農(nóng)業(yè)機械學報,2020,51(s1):227-235. ZHANG Rongfang, JIAO Wei, ZHOU Jilei, QI Bing, LIU Hu, XIA Qianqian. Parameter Calibration and Experiment of Rice Seeds Discrete Element Model with Different Filling Particle Radius[J]. Transactions of the Chinese Society for Agricultural Machinery,2020,51(s1):227-235.

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  • 收稿日期:2020-07-30
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  • 在線發(fā)布日期: 2020-11-10
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