共查询到20条相似文献,搜索用时 15 毫秒
1.
《Journal of Agricultural Engineering Research》1996,63(4):301-314
This paper considers the engineering design, operation, functional performance, product quality, and economic analysis of a natural gas heated-air batch hay drier that operates with an automatic bale wagon. The automatic bale wagon and a track are used for loading and off-loading stacks of alfalfa and timothy hay en masse to and from the drier. The newly developed batch hay drier has two identical drying units in a gable roof building, and each drying unit has a large axial flow fan which forces about 450 m3/min of air by negative pressure through 22-32 t (a maximum of five stacks) of small rectangular hay bales placed to dry on the perforated extended metal grate floor of the drier. Top plenum swing-away frames, with attached polyethylene curtains, were used for effectively sealing the vertical sides and one end of the hay stacks.Batches of hay, initially at about 25-40% moisture content wet basis (w.b.) were successfully dried to 12-15% final moisture content in 17-37 h at moderate drying air temperatures of 45±5°C. The drying capacity was 1·0 t dried hay/h, specific fuel consumption 26 m3/t, specific energy consumption 4790 kJ/kg water evaporated, and drying energy cost Canadian $5·82/t when hay was dried from an initial moisture content of 30% w.b. to a final value of 15% w.b. The hay produced by the drier was of high quality with an attractive green color. 相似文献
2.
3.
4.
介绍远红外果蔬干燥机电气控制的特点及工作原理。系统应用远红外辐射干燥技术,连续传动的干燥方式,根据蔬菜的品种及含水量,可对各个温区的温度及干燥时间进行控制。 相似文献
5.
6.
脱水菜专用混流式隧道干燥机改进设计 总被引:4,自引:0,他引:4
对现有的混流式隧道干燥机进行了改进,用以取代脱水菜生产中普遍使用的风机顶置逆流式隧道干燥机。改进后的干燥机,热空气流动均匀,废气热能合理回收利用,能一次完成干燥。用胡萝卜块做的试验表明,脱每千克水降低能耗3440kJ,节能26%,产品脱水一致,缩短了生产时间。 相似文献
7.
8.
9.
根据非平衡态热力学和相平衡理论,建立了多孔介质对流干燥内部传质模型、传热模型,该模型充分考虑了传热与传质之间的相互藕合关系。用VB编程软件对该模型进行了分析求解,设计开发模拟软件。以切片土豆为例进行传质模拟计算,并与土豆片干燥实验数据进行对比,结果表明:模拟值和实测值十分接近,二者的最大相对偏差小于9.1%。模拟结果显示土豆对流干燥中内部水分由内往外迁移,以及干燥过程中产生的表低内高水分分布规律。 相似文献
10.
11.
牧草是发展畜牧业的基础,但由于其地理分布和自身松散的特性,导致牧草储运成本过高,通常需要对牧草进行压缩打捆处理。牧草压缩过程中预压缩阶段位移大压力小,致密阶段位移小压力大,压缩过程中牧草的压缩特性不断变化。为此,设计了一凸轮式牧草压捆机,利用凸轮能够实现复杂运动的特点,使牧草在压缩过程中进行变速压缩,符合压缩特性曲线的变化规律。通过Pro/E软件对整机进行干涉检测以及运动学仿真模拟,结果表明:该机构可以实现快速进行预压缩、慢速进行压紧阶段的压缩,进而提高牧草压缩效率并达到降低能耗的目的。 相似文献
12.
洞道混合式干燥机性能分析及结构设计 总被引:1,自引:0,他引:1
通过对洞道混合式干燥机气流状态的测试分析,对该机型的结构进行了改进设计。提出了将风机位置下移、增加风机数量、中部排气减压等设计方案。实践表明,改进设计加强了干燥机气流分布的均匀性,加快了干燥速度,简化了设备结构,强化了生产的连续性,热效率由原来的45%提高到63%。 相似文献
13.
14.
A computer model was developed to simulate forage systems on dairy farms. The model simulated alfalfa growth, corn silage and corn grain yields, harvest, storage, feeding and ration formulation for a dairy herd. A 26-year series of historical weather data from East Lansing, Michigan, was used to compare management and technological alternatives on the basis of average net return and year-to-year variations. For example, a four-cut alfalfa system was found to be more profitable than a three-cut system 90% of the time. The comparison of a hay system with a silage system was very sensitive to forage intake assumptions; the break-even point shifted from 120 ha to 40 ha when silage intake was increased by 5%. The model can be used to assess the impact of new forage conservation methods under a wide range of climatic and management conditions. 相似文献
15.
《Agricultural Water Management》2002,57(2):111-126
The macroscopic root water uptake approach was used in the numerical simulation model HYSWASOR to test four different pressure head-dependent reduction functions. The input parameter values were obtained from the literature and derived from extensive measurements under controlled conditions in the greenhouse. The simulation results indicated that the linear reduction function cannot fit the data satisfactorily. Most of the existing non-linear reduction functions can fit only half of the data range, while the best agreement is obtained with the non-linear two-threshold reduction function. The parameter values obtained by calibration differ only slightly from those of the experiments. Soil water pressure head heterogeneity over the root zone does not play an important role in water uptake. The roots appear to take up water from the relatively wetter parts of the root zone to compensate for the water deficit in the drier parts. While the simulated transpiration agrees closely with the experimental data, the main reason for the discrepancy between the simulated and actual water contents appears to be water uptake during the night. 相似文献
16.
17.
基于虚拟样机技术的牧草高密度压捆过程分析 总被引:4,自引:2,他引:2
针对直接利用高密度压捆机对牧草高密度压缩过程进行研究时,传统的试验研究和理论分析方法存在的问题,对牧草的高密度压捆过程进行了计算机分析与仿真研究。引入了虚拟样机技术,使用ADAMS软件对牧草的高密度压捆过程进行分析,建立压缩过程中牧草的ADAMS模型,并对ADAMS的建模方式、模型结构进行了验证。通过分析获得模拟弹簧的刚性系数k随时间的变化规律,进而对牧草压缩工况进行优化分析。 相似文献
18.
19.
热泵式节能烘干机的设计 总被引:2,自引:0,他引:2
热泵是一种使热量从低温介质流向高温介质,以对高温物体进行供热的装置.为此,利用热泵原理研究设计了一种小型高效节能烘干机,并介绍了该机的主要特点、总体结构等,尤其对热泵、烘干床进行了详细介绍.该机具有结构简单新颖、造价低廉、使用寿命长、高效节能等优点,不仅可以烘干多种农产品,还可以烘干茶叶、蘑菇等多种农副产品. 相似文献
20.
近年来,批式循环谷物干燥机(以下简称干燥机)发展较快,安徽省涌现一些专业生产干燥机的企业。干燥机以其经济实用、及时干燥谷物、占地面积较小、可以单独和组合使用而广受用户青睐。笔者参加了一些干燥机的试验鉴定,现就检测中遇到的常见问题做些解析。 相似文献