农业工程学报
農業工程學報
농업공정학보
2015年
8期
76-83
,共8页
雷军乐%王德福%张全超%杨星%李利桥%李超
雷軍樂%王德福%張全超%楊星%李利橋%李超
뢰군악%왕덕복%장전초%양성%리리교%리초
流变%应力松弛%优化%完整稻秆%圆捆机%卷压过程
流變%應力鬆弛%優化%完整稻稈%圓捆機%捲壓過程
류변%응력송이%우화%완정도간%원곤궤%권압과정
rheology%stress relaxation%optimization%intact rice straw%round baler%compression process
为深入研究完整稻秆在卷捆压缩过程中的流变特性，该文利用自制的钢辊式圆捆机卷压试验台进行了完整稻秆卷压过程应力松弛试验研究。选择稻秆含水率、草捆干物质质量、卷捆钢辊转速、稻秆喂入速度为试验因素，并以应力松弛时间和平衡弹性模量作为应力松弛特性评价指标，进行4因素5水平正交旋转组合试验。结果表明：完整稻秆卷压过程应力松弛模型可用1个Maxwell单元和1个弹簧并联组成的三元件方程表示；各因素对应力松弛时间贡献率排序依次为稻秆含水率、草捆干物质质量、稻秆喂入速度、卷捆钢辊转速；对平衡弹性模量贡献率排序依次为草捆干物质质量、稻秆含水率、稻秆喂入速度、卷捆钢辊转速；当稻秆含水率为65%、草捆干物质质量为17 kg、卷捆钢辊转速为257 r/min、稻秆喂入速度为1.6 kg/s时，应力松弛时间和平衡弹性模量可分别达最佳值17.08 s和4.01 kPa。试验结果可为圆型打捆机对完整稻秆的卷压工艺优化及其压缩机理分析提供必要的理论与技术支持。
為深入研究完整稻稈在捲捆壓縮過程中的流變特性，該文利用自製的鋼輥式圓捆機捲壓試驗檯進行瞭完整稻稈捲壓過程應力鬆弛試驗研究。選擇稻稈含水率、草捆榦物質質量、捲捆鋼輥轉速、稻稈餵入速度為試驗因素，併以應力鬆弛時間和平衡彈性模量作為應力鬆弛特性評價指標，進行4因素5水平正交鏇轉組閤試驗。結果錶明：完整稻稈捲壓過程應力鬆弛模型可用1箇Maxwell單元和1箇彈簧併聯組成的三元件方程錶示；各因素對應力鬆弛時間貢獻率排序依次為稻稈含水率、草捆榦物質質量、稻稈餵入速度、捲捆鋼輥轉速；對平衡彈性模量貢獻率排序依次為草捆榦物質質量、稻稈含水率、稻稈餵入速度、捲捆鋼輥轉速；噹稻稈含水率為65%、草捆榦物質質量為17 kg、捲捆鋼輥轉速為257 r/min、稻稈餵入速度為1.6 kg/s時，應力鬆弛時間和平衡彈性模量可分彆達最佳值17.08 s和4.01 kPa。試驗結果可為圓型打捆機對完整稻稈的捲壓工藝優化及其壓縮機理分析提供必要的理論與技術支持。
위심입연구완정도간재권곤압축과정중적류변특성，해문이용자제적강곤식원곤궤권압시험태진행료완정도간권압과정응력송이시험연구。선택도간함수솔、초곤간물질질량、권곤강곤전속、도간위입속도위시험인소，병이응력송이시간화평형탄성모량작위응력송이특성평개지표，진행4인소5수평정교선전조합시험。결과표명：완정도간권압과정응력송이모형가용1개Maxwell단원화1개탄황병련조성적삼원건방정표시；각인소대응력송이시간공헌솔배서의차위도간함수솔、초곤간물질질량、도간위입속도、권곤강곤전속；대평형탄성모량공헌솔배서의차위초곤간물질질량、도간함수솔、도간위입속도、권곤강곤전속；당도간함수솔위65%、초곤간물질질량위17 kg、권곤강곤전속위257 r/min、도간위입속도위1.6 kg/s시，응력송이시간화평형탄성모량가분별체최가치17.08 s화4.01 kPa。시험결과가위원형타곤궤대완정도간적권압공예우화급기압축궤리분석제공필요적이론여기술지지。
In recent years, rice straw as a kind of renewable material is being used widely in China. The rheologic characteristics of crop straw have great effect on the power consumption, productivity and compression process of compressing equipment, as well as on the bale durability. At present, a lot of researches have been done by many domestic and foreign scholars on the compression rheologic characteristics, but the researches have been aimed at the rectangular baler instead of the steel-roll round baler, and the test materials are mainly concentrated on corn straw, wheat straw and alfalfa, which limit the development and application of the round baler for crop straw in China. Stress relaxation is an important phenomenon in the rheologic characteristics of straw. In order to deeply research stress relaxation phenomenon of intact rice straw during rotary compression under the round baler, a steel-roll round baler was used for rotary compression test in this paper. To timely monitor the force during rotary compression, the force testing device was developed. In experiments, moisture content of rice straw (12%-68%), dry material quantity of bale (15-23 kg), steel roll speed (222-318 r/min) and feeding speed of rice straw (0.4-1.6 kg/s) were chosen as experimental factors, which were at 5 levels. Stress relaxation time and balance elastic modulus were decided as the evaluation indices, and quadratic orthogonal rotatory combination design was used to analyze the effect of different factors. Through analyzing experimental data by Matlab 8.0, the stress relaxation model of intact rice straw during rotary compression could be expressed by three-element equation which was available through the parallel connection of one Maxwell unit and one spring. The regression equations of stress relaxation time and balance elastic modulus had been established respectively by using Design Expert software. Through variance analysis of regression equations for stress relaxation time and balance elastic modulus, the coefficients of determination (R2) for the models were 0.96 and 0.97 respectively, which indicated that the proposed model was agreeable with the practical condition, thus the proposed model could be used to predict the change of the stress relaxation time and balance elastic modulus during rotary compression. In addition, the relations between evaluation index and each single factor were shown in response surface. The results showed that:with the increase of moisture content of rice straw, both of stress relaxation time and balance elastic modulus decreased;with the increase of dry material quantity of bale, stress relaxation time decreased and balance elastic modulus increased;with the increase of steel roll speed, stress relaxation time and balance elastic modulus decreased and then increased;and with the increase of feeding speed of rice straw, stress relaxation time decreased and balance elastic modulus increased gradually. The contribution rate of each factor on stress relaxation time was as follows:moisture content of rice straw>dry material quantity of bale>feeding speed of rice straw>steel roll speed. The contribution rate of each factor on balance elastic modulus was as follows:dry material quantity of bale>moisture content of rice straw>feeding speed of rice straw>steel roll speed. When moisture content of rice straw was 65%, dry material quantity of bale was 17 kg, steel roll speed was 257 r/min and feeding speed of rice straw was 1.6 kg/s, stress relaxation time was 17.08 s and the balance elastic modulus was 4.01 kPa, which were the best results. The research provides theoretical and technical support for the process optimization of round baler, as well as the analysis of its compression mechanism.
