共查询到20条相似文献,搜索用时 453 毫秒
1.
风道的尺寸大小对混流式粮食干燥机的干燥效率有很大影响。旨在研究分析混流式粮食干燥机角状盒尺寸对干燥室内风场的场强大小的影响以及对场强均匀度的影响。利用ANSYS/FLOTRAN系统对3种不同尺寸的角状盒设计进行模拟仿真。模拟在粮食卸载量、风量以及角状盒形状为定量的条件下,3种不同尺寸的角状盒所形成的风场场强大小和场强分布的均匀度。分析比较3种模拟结果,并选择出场强分布最均匀且场强大小最合理的优化方案以提高干燥机的干燥效率。 相似文献
2.
3.
《农业装备与车辆工程》2015,(4)
以一款低速电动乘用车为研究对象,讨论了车身静态分析有限元模型的建立过程。提出了基于一维搜索的车身轻量化设计方法,以应力为约束条件,零件质量最小为目标函数,对车身结构进行轻量化优化设计。优化后车身零件的应力值都向屈服极限靠拢,实现材料的充分利用。最后通过对比采用全局优化方法和整体优化与局部厚度改进相结合的优化方法发现,采用整体优化与局部改进的设计方法对提高材料的利用率更有效。 相似文献
4.
热带牧草的干燥品质关系着热带畜牧业的发展。由于海南岛太阳辐射强度大,因而设计了用于太阳能干燥热带牧草的平台,其主要由太阳能集热器、风机、干燥仓、风道和控制系统等组成。针对干燥平台设计优化了太阳能集热器,对其结构、吸热涂层材料、上下通道距离比值、串并联连接方式等对集热效率的影响进行实验研究,并设计一套自动跟踪太阳能集热器系统,最终确定优化的实验平台。太阳能干燥热带牧草成本低、环保、效率高,具有广阔的市场前景。 相似文献
5.
6.
槽轮机构广泛应用于各种机械中.针对灯笼状荔枝果肉获取机械中的槽轮机构,通过动力分析建立槽轮工作阻力矩和拨盘驱动力矩间关系的数学模型,利用Pro/E软件建立槽轮机构的三维参数化模型,并进行静态应力分析和全局敏感度分析.结果表明:槽轮工作中受到的静态应力小于材料的抗剪刚度;槽轮的厚度越大,在同样的工作载荷下所受到的静态应力就越小.上述结果给送料机构的改进设计和制造提供了依据. 相似文献
7.
8.
为了提高汽车的被动安全,并实现轻量化设计,基于LS-DYNA和HyperWorks软件建立了吸能盒的仿真模型,并进行了模拟仿真。首先分析了相同尺寸的钢制和铝制两种材料吸能盒的吸能特性,然后在材料成本相同时,对吸能盒的壳体结构进行改进,最后将仿真结果与理论结果进行对比。分析结果可知:在碰撞工况相同时,铝制吸能盒的比吸能是钢制吸能盒的2.8倍,同时重量减轻63%。对铝制吸能盒内壁结构进行改进,得到了一种综合指标较好的“目”字形吸能盒结构。 相似文献
9.
10.
注剂式带压堵漏技术是在特定条件下实施的一项应急修补技术,堵漏夹具又是注剂式带压密封技术的核心。在设计夹具时,泄漏孔处的压力是带压密封夹具厚度计算的重要参数,它直接影响了夹具的设计厚度,因此利用CFD方法对泄漏管道进行分析,通过夹具设计压力参数优化使其更加精确为原计算压力的85%。通过ANSYS应力验证,验证了优化后的设计的夹具仍然符合选用材料的许用应力,并且达到了轻量化设计的目标。 相似文献
11.
12.
13.
14.
15.
《Journal of Agricultural Engineering Research》1998,69(3):249-254
A model to represent the discolouration of dried powder of carrots as a function of temperature was developed. Two types of carrots, Asian and European, containing large amount of lycopene and β-carotene, respectively, were tested. The dried powder was stored under an atmosphere with O2and at three different temperatures, 5,20 and 35°C. The surface colour of the powder was monitored during storage by a Hunter colour ratioa/b. In the proposed model, the rate of oxidation was assumed to be represented by the product of the fraction of concentration of oxidized pigment at arbitrary time and a specific rate of oxidation of pigment. The rate parameters in the proposed model were calculated by fitting the experimental data with smooth curves by trial and error at the end of the induction period but before discolouration took place. The frequency constant and activation energy, expressing the temperature dependence of the rate parameters, were expressed by the Arrhenius relation. The simulation results of a Hunter colour ratioa/bof dried powder at 25°C showed good agreement with the experimental data, suggesting that the proposed model was effective for the prediction of discolouration of dried powder of both types of carrot. The use of the induction period in the manner described may enable the shelf life of dried powder to be predicted. 相似文献
16.
17.
18.
The fractional outflow rate of water from the rumen, measured as the rate of disappearance of the chromium complex of ethylenediamine tetra-acetic acid, was related to a number of dietary factors. A multiple regression equation was derived which expressed fractional outflow rate as a function of the intakes of dry matter, ash, acid-detergent fibre and crude protein.The data analysed consisted of 243 observations for sheep on 59 diets, including forage, concentrate and mixed diets. The ranges covered by the data were: fractional outflow rate 0.7–3.6 day?1; dry matter intake 560–1400g/day; ash 4–30%, acid-detergent fibre 7–41%, crude protein 5–26 % of dry matter; there were no observations for sheep of less than 34 kg liveweight.The equation accounted for 56·3 % of the total variance. Between-sheep variance could not be calculated for the whole of the data but was undoubtedly substantial since, for a sixth of the data, it was known to account for 38 % of the total variance. 相似文献
19.
感官检验棉花的品级,这是农村常见的一种检测手段.它的一个主要特点就是存在不确定性.这是由于检验员的品级检验水平存在一定的差异,其中有很多因素制约着检验的结果.文章对影响感官检验结果的因素进行了系统的分析. 相似文献
20.
从灾害经济学的角度探讨了城镇供水优化调度的必要性和可能性,认为在缺水不可避免的情况下,对供水进行优化调度可以减小缺水带来的损失,产生较好的减灾效益,特别是可以大大减小严重干旱的灾害效应。并根据水资源的特性,提出了缺水损失的计算模式以及优化调度的原则和方法。 相似文献