环境湿度场与不同包装种子含水率的研究——基于COMSOL
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摘要
为掌握除湿过程湿度场分布及作用于种子含水率的规律,针对压差原理的贮藏箱体,以水稻种子为试验物料,基于COMSOL Multiphysics5.0软件,对不同湿度环境湿度场分布和不同包装种子在不同湿度场中随时间变化的种子含水率进行数值模拟,得出了不同包装种子在不同湿度环境下贮藏7天的种子含水率与湿度场云图。研究结果表明:同一包装的水稻种子在不同湿度环境下具有不同的吸湿或解吸速率。95%高湿环境下散装的种子平均吸水速率可达1.79×10~(-2)mol/d,用铝箔袋包装平均吸湿速率仅有0.2×10~(-2)mol/d,是散装包装的1/9;35%超干燥环境下散装的种子平均解吸速率可达0.68×10~(-2)mol/d,贮运7天后含水率可降到9%;5 0%湿度环境下贮运7天后含水率可达到11%,但前者能耗是后者能耗的4倍多。通过与验证试验对比,试验结果与模拟结果基本吻合,试验值与模拟值最大偏差值为1.2%,该模型是有效的。
In order to obtain the distribution of humidity field and the rule of seed moisture content,a transport container for storage with dehumidifier based on differential pressure principle was investigated. In this study,rice seeds were used as the test material. It was used the Finite Element analysis software COMSOL Multi-physics 5. 0,The humidity field of different humidity environment and seed moisture content of different packing seeds in different humidity field were simulated. The seed moisture content and the humidity field cloud charts of different packing seeds were obtained under different humidity environment for 7 days. The results showed that the rice seeds with the same package had different moisture absorption and desorption rates under different humidity conditions. The average bibulous rate of seeds in unpacked in 95% high humidity environment could be achieved1. 79 × 10~(-2) mol/d,The average bibulous rate of seed in aluminum foil packing only 0. 2 × 10~(-2) mol/d,Which was one ninth of the former. The average water loss rate of seeds in unpacked in 35% dry environment could be achieved 0. 68 × 10~(-2) mol/d. The rice seeds moisture content in unpacked could be reduced to 9% after 7 days storage and transportation. And the rice seeds moisture content in unpacked could be up to 11% in 50% humidity environment after 7 days. However,Energy consumption of the former was more than four times the energy consumption of the latter. The test results and the simulation results was consistent. The maximum deviation value of simulation and test values is only 1. 2%. This model is valid. There is a certain reference value to design warehouse dehumidification system and select the packaging way.
In order to obtain the distribution of humidity field and the rule of seed moisture content,a transport container for storage with dehumidifier based on differential pressure principle was investigated. In this study,rice seeds were used as the test material. It was used the Finite Element analysis software COMSOL Multi-physics 5. 0,The humidity field of different humidity environment and seed moisture content of different packing seeds in different humidity field were simulated. The seed moisture content and the humidity field cloud charts of different packing seeds were obtained under different humidity environment for 7 days. The results showed that the rice seeds with the same package had different moisture absorption and desorption rates under different humidity conditions. The average bibulous rate of seeds in unpacked in 95% high humidity environment could be achieved1. 79 × 10~(-2) mol/d,The average bibulous rate of seed in aluminum foil packing only 0. 2 × 10~(-2) mol/d,Which was one ninth of the former. The average water loss rate of seeds in unpacked in 35% dry environment could be achieved 0. 68 × 10~(-2) mol/d. The rice seeds moisture content in unpacked could be reduced to 9% after 7 days storage and transportation. And the rice seeds moisture content in unpacked could be up to 11% in 50% humidity environment after 7 days. However,Energy consumption of the former was more than four times the energy consumption of the latter. The test results and the simulation results was consistent. The maximum deviation value of simulation and test values is only 1. 2%. This model is valid. There is a certain reference value to design warehouse dehumidification system and select the packaging way.
引文
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[2]陈年伟,张体刚.高温贮存环境对杂交水稻种子发芽率的影响研究[J].杂交水稻,2011,26(2):29-31.
[3]侯文平,王成瑷,赵磊,等.贮存环境对水稻种子芽率及水分的影响[J].种子科技,2014,32(8):27-30.
[4]吴贻开,陈文杰,李清华,等.相对湿度对水稻种子贮藏寿命的影响[J].福建农业科技,2000(4):6-7.
[5]李淑君,王惠泉,赵文玉,等.基于COMSOL多物理场耦合仿真建模方法研究[J].机械工程与自动化,2014(4):19-20,23.
[6]Torres S S,Bautista E H,Ramirez J R,et al.Numerical simulation of warm-air drying of mexican softwood:an empirical and mechanistic approach[J].Chemical and Biochemical Engineering Quarterly,2014,28(1):125-133.
[7]Huang Z,Marra F,Wang S J.A novel strategy for improving radio frequency heating uniformity of dry food products using computational modeling[J].Innovative Food Science&Emerging Technologies,2016(34):100-111.
[8]许明杰,于冬华,王克峰,等.基于COMSOL Multiphysic的CO变换反应的数值模拟与优化[J].辽宁化工,2013,42(5):514-519.
[9]邵学良,刘志伟,陆晖,等.稻谷水分含量测定方法的比较[J].粮食储藏,2009,38(3):52-54.
[10]Zhang Q,Yang W,Sun Z.Mechanical properties of sound and fissured rice kernels and their implications for rice break age[J].Journal of Food Engineering,2005,68(1):65-72.
[11]秦小艳,王宏图,朱艺文,等.COMSOL的非煤地下矿山机械通风系统研究[J].中国科技信息,2012,(21):45,52.
[12]刘妍华,曾志雄,郭嘉明,等.增施CO2气肥对温室流场影响的数值模拟及验证[J].农业工程学报,2015,31(12):194-199.
[13]郭嘉明,方思贞,曾志雄,等.管道式加湿装置湿度场分布的数值模拟及试验验证[J].农业工程学报,2015,31(16):57-64.
[14]徐轶,徐青.基于COMSOL Multiphysics的渗流有限元分析[J].武汉大学学报:工学版,2014,47(2):165-170.
[15]陶文铨.数值传热学[M].2版.西安:西安交通大学出版社,2002.
[16]郭嘉明,吕恩利,陆华忠,等.保鲜运输车果蔬堆码方式对温度场影响的数值模拟[J].农业工程学报,2012,28(13):231-236.
[17]朱红钧,林元华,谢龙汉.FLUENT流体分析及仿真使用教程[M].北京:人民邮电出版社,2010.
[18]张馨予.种子仓储除湿系统的试验与仿真研究[D].广州:华南农业大学,2016.