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1.
Ventilation design is the difficulty of transformer room design. Temperature field and velocity field in a transformer room was simulated by CFD method . By comparing simulation value with the experimental value in related document , the effectiveness of the mathematical model was verified. Based on it, an indoor substation transformer built was taken as the simulation object, then designed and simulated six kinds of ventilation condition by changing the location and area of air inlet, focused on the influence of air inlet on the ventilation effect by comparing the temperature field ,velocity field and temperature characteristic value in different condition. The simulation results show that when air inlet area is fixed, the air inlet should be arranged in the radiator side and its center height should be controlled in the radiator center height or slightly offset position, it should not be higher than the radiator. When the air inlet location is fixed, air inlet area should be increased along the high direction to improve ventilation effect. The conclusions can provide technical support for the ventilation design of transformer room. 相似文献
2.
Lattice Boltzmann method is used to simulate the methanol steam reforming process in a micro channel. Lattice evolution model with dual rate kinetic parallel reaction mechanism is established. The impacts of boundary temperature, inlet velocity on reaction outlet parameters, such as methanol conversion rate, outlet concentrations of hydrogen and carbon monoxide and maximum temperature difference, are studied. It is found that under a certain boundary temperature and inlet velocity, when the methanol molar ratio, boundary temperature and inlet velocity are 1.3, 523 K and 0.1 m/s respectively, the methanol conversion ratio can reach the highest value of 94.36%, together with the concentrations of hydrogen and carbon monoxide of 0.098 9 and 0.009 5% respectively. With the increase of boundary temperature and decrease of inlet velocity, the concentration of CO will increase. 相似文献
3.
In order to investigate the effects of inlet temperature,velocity and water methanol molar ratio on methanol- steam reforming for hydrogen production in microreactor, we carry out 3-D simulation of methanol-steam reforming for hydrogen production in self-designed plate microreactor with the application of general finite reaction rate model in CFD software of FLUENT, The kinetics used are DE and SR model, The results show that, At the conditions of inlet velocity, temperature and water methanol molar ratio are 2.88 m/s, 493 K and 1.3 respectively, methanol conversion at the reactor outlet reaches 79.8%. Through the simulation, we can see that in microreactor it can be maintain higher hydrogen molar fraction and methanol conversion at high reactant flow rate. 相似文献
4.
农产品热泵烘房温度场均匀性是影响农产品干燥品质的重要因素。本文选用5HGR-35型农产品热泵烘房,通过交互式CAD/CAM系统(UG)软件建立热泵烘房3D模型,运用理论分析与计算流体动力学(Computational fluid dynamics,CFD)模拟相结合的方法,研究其内部温度场分布情况,对现有结构烘房的温度场建模模拟,分析模拟结果并对现有结构进行优化。通过模拟得出结论:送风速度越大,烘房内热空气更新越快,换热效果越好。综合温度场分布以及农产品烘干要求,烘房内合理的送风速度为11 m/s左右;在11 m/s风速下,烘房空载时在15 min左右达到设定温度(65℃);小推车设计高度加大300~310 mm烘房内部温度场更均匀;烘房顶部均匀加入3块长×宽×高=2900 mm×20 mm×300 mm的挡板,可以使烘房内部温度场更均匀;小推车与烘房之间及相互之间保持30 mm左右间隙摆放更有利于烘房内部温度场的分布;验证试验中,模拟温度与实测温度吻合性良好。上述结论对烘房的进一步优化设计具有一定的指导意义。 相似文献
5.
选用7种不同细胞质源滇型不育系与滇一型保持系及恢复系各5个材料进行杂交,对70个杂交组合的剑叶穗颈夹角、剑叶长宽比、株高、穗长及穗总粒数这5个性状进行分析。试验结果表明,滇型杂交水稻在剑叶长宽比、株高、穗长及穗总粒数等性状的表现主要受不育系母本的影响,在组配滇型杂交稻时考虑不育系多项农艺性状的表现显得尤为重要。 相似文献
6.
The research object is the coupled heat transfer effect between freezing soil,water and horizontal heat exchange tube,use finite volume numerical method to dispersed solving for continuity equation and heat transfer equation of unsaturated freezing soil,gives part of the temperature fields and freezing percentage distribution graphs,and analyzes the reason of the coupled heat transfer.The analysis result shows that:the temperature field of freezing soil are some horizontal lines parallelling to the ground surface.The peak value of solid-liquid phase change region appears in the upper part where there is backwater pipe,the low value appears in the place where there isn't horizontal heat exchange tube.The horizontal heat exchange tube makes the freezing front deviate towards the ground surface.The arrangement difference of inlet and outlet position of horizontal heat exchange tube will effect the size and position of the phase change region of freezing soil.Arranging the backwater pipe at one side or middle position is the optimized mode. 相似文献
7.
采用盆栽人工控水的方法,研究不同小豆品种根系对干旱胁迫的响应。结果表明,干旱胁迫抑制了小豆根系的生长,随着干旱胁迫的加剧,小豆的最大根长呈先增加后减少的趋势,根重、总根长、根表面积、根体积、株高、茎粗和叶面积呈减小的趋势,根冠比呈增加的趋势;不同品种小豆对干旱胁迫的响应存在差异,抗旱型品种的根重、总根长、根表面积、根体积、株高、茎粗和叶面积随干旱胁迫的加剧下降幅度小,根冠比显著加大。重度干旱胁迫下,品种间最大根长、根重、根体积、株高、茎粗、叶面积和根冠比差异在整个生育期间达显著水平。抗旱型品种冀红8937的根系更为发达,根冠比较高,中度干旱胁迫下,最大根长的增加幅度较大,随着干旱胁迫的加剧,其根重、总根长、根表面积、根体积、株高、茎粗和叶面积下降幅度较小,根冠比显著增加。 相似文献
8.
莲藕克隆构型与环境的关系 总被引：3，自引：0，他引：3
对莲〔Nelumbo nucifera Gaertn〕在水田及鱼塘的克隆生长格局进行了研究,调查了三个或三个以上的品种莲的叶片大小、叶柄高度、节间长度、分枝角度、分枝节位、结藕节位等参数。结果表明,莲根茎分枝类型为单轴型,新生的次生根茎交替着水平伸向上级根茎的两侧,分枝角度62.6~98.7°,品种之间存在差异。不同品种莲叶柄高度、叶柄粗度、根状茎节间长度、根状茎节间粗度随着植株生长越来越大,与以前报道并不一致。主枝结藕节位可作为判断莲藕熟性的指标之一。莲克隆构型在不同品种、不同生长环境之间有明显差异。 相似文献
9.
OsGA20ox2不同长度RNAi片段对水稻株高等农艺性状的遗传效应 总被引：1，自引：0，他引：1
利用OsGA20ox2基因序列构建不同长度的RNAi片段并导入水稻，获得不同高度的矮化植株。将这些矮化植株与野生型植株回交获得B1F2群体，卡方检测表明B1F2群体矮秆植株数和高秆植株数符合3∶1比例，表现为矮秆显性的遗传规律。对矮化植株的F5和B1F2群体株高、各茎节间长度和一些主要农艺性状方差分析显示, OsGA20ox2基因的RNAi能显著缩短株高和各节间长度(P<0.05)，RNAi干扰片段越长，使植株株高和节间长度缩短程度越大，可使株高降低24~42 cm，矮化22%~39%。在同一长度的RNAi干扰片段下，倒一节节间长度平均缩短与倒二节节间长度平均缩短非常相近，倒三节和倒四节节间长度平均缩短非常相近，总的缩短程度是倒四节>倒三节>倒二节>倒一节。这种近基部节间长度缩短幅度和比例较大的特点，利于提高水稻的抗倒伏能力，同时上部节间缩短幅度和比例较小，有效地保持合理株高，不使生物产量明显降低，有利于水稻的稳产和高产。OsGA20ox2基因的RNAi不影响如千粒重、结实率、穗长等其他主要农艺性状或影响很小。 相似文献
10.
三种不同类型大豆及其杂种后代主要农艺性状的配合力分析 总被引：4，自引：0，他引：4
利用具有明显差异的3种不同进化类型的大豆，采用双列杂交方式配制类型内及类型间共15个杂交组合。结果表明，不同类型大豆主要农艺性状的一般配合力明显不同。秣食豆在株高、节间长、分枝数、单株荚数和单株粒数等性状上具有增效作用；在粒茎比和收获指数等性状上具有减效作用。亚有限类型大豆则有降低株高和节间长度，提高 相似文献
11.
Y形偏心支撑高强钢框架结构抗震性能 总被引：3，自引：1，他引：2
在Y形偏心支撑高强钢框架结构抗震性振动台试验的基础上,建立了试验试件的有限元模型,并验证了分析的正确性。设计了一个9层的Y形偏心支撑高强钢框架结构,以耗能梁段长度、耗能梁段腹板高厚比、高跨比为参数,对9层结构进行了非线性动力时程分析,研究了以上参数对结构抗震性能的影响。研究结果表明,改变耗能梁段长度、高跨比对结构层间侧移、耗能梁段性能、框架柱弯矩、耗能能力均有不同程度的影响,对框架柱轴力、基底剪力无显著影响;改变耗能梁段腹板高厚比对结构耗能能力有影响,对结构层间侧移、耗能梁段性能、框架柱受力、基底剪力无显著影响,并给出了相关设计建议。 相似文献
12.
为得出直墙拱形巷道围岩应力分布规律,应用复变函数弹性理论推导了直墙拱形巷道围岩应力分布的解析表达式。对直墙拱形巷道边界的围岩应力和巷道水平线方向的围岩应力分布规律进行分析,并考虑直墙拱形巷道断面高宽比和侧压系数对其影响规律。研究表明：在不同巷道断面高宽比、侧压系数下,直墙拱形巷道围岩应力集中区域主要集中在直墙底部底角处、拱形顶板中点附近和底板中部3个位置。不同巷道断面高宽比下,直墙拱形巷道沿水平线的应力分布规律基本相同。侧压系数大于1时,采用巷道断面高宽比小于1较有利于巷道稳定;侧压系数小于等于1时,采用巷道断面高宽比大于1较有利于巷道稳定。 相似文献
13.
In order to find out a space sense indicator that can present the real appearance of human and natural in urban lighting environment, three common used indicators are studied, which are ratio of vertical illuminance to semi cylindrical illuminance, ratio of vertical illuminance to horizontal illuminance and ratio of average cylindrical illuminance to horizontal illuminance.An on site test is taken at Three Gorges Square Pedestrian Street of Chongqing. The variation law of ratio of vertical illuminance to horizontal illuminance is approximate to ratio of average cylindrical illuminance to horizontal illuminance, which varies with the changing of measure point location and reach maximum at the axial central section of pedestrian street between two streetlamps. The change of ratio of vertical illuminance to semi cylindrical illuminance is small correspondingly and it is more appropriate to be as a lighting quality indicator with space sense for urban illuminance environment. 相似文献
14.
流固耦合的多元结构深厚覆盖层透水地基的力学特性 总被引：3，自引：0，他引：3
深厚覆盖层多元结构坝基在渗流过程中各土层力学差异明显,分析时关注的具体问题也不尽相同,需要深入研究。基于比奥固结理论,考虑土体的非线性流变以及土体固结变形过程中孔隙度、渗透系数、弹性模量及泊松比的变化;借助ADINA流固耦合模块来模拟西藏达嘎水电站坝基渗流场与应力场耦合过程,分析各层力学特性及相互作用。研究表明,透水性较强的表层土体是渗流主要通道,也是渗流进出区和沉降变形体现区,应在上游采取措施提高其压缩模量,下游区域增设反滤层和排水设施;坝基中的粉细砂层是坝基沉降的主要原因,对坝基沉降起主导作用,同时应注意其液化特性对坝基的不利影响;坝基中的承压含水土层对下游上部结构产生向上顶托力,若位置较深,则破坏性较小;坝基深部土层对整个坝基的渗流破坏影响较小,但对沉降和渗流量的影响不可忽视;表层砂卵砾石层和粉细砂层的渗透系数相差较小时,土层间不会发生接触冲刷。此外,还发现坝基孔隙水压力在快速衰减阶段被消散,期间土体固结较快。垂直防渗墙能有效降低渗透坡降和渗流量,将坝基沉降变形控制在防渗墙上游区域,但上游坝基变形对防渗墙产生较大的水平推力,应加大防渗墙尺寸或者采用辅助渗控措施。 相似文献
15.
采用二因素随机区组试验设计,通过测定苗鲜重、根鲜重、苗干重、根干重、叶片数、株高、茎粗、根长、根条数、节长、节数和叶面积等生长指标,研究了品种和外植体对马铃薯脱毒试管苗生物量,地上部和地下部的影响。研究结果表明:3个不同成熟期品种、3种不同外植体部位对马铃薯单株根鲜重、苗干重、根干重、株高、茎粗、节长和根冠比影响有显著性交互作用(p<0.05),说明不同品种和外植体对马铃薯脱毒试管苗生长发育有直接影响,其余性状受品种和外植体交互作用影响不显著;3个不同成熟期品种马铃薯的苗鲜重、根鲜重、苗干重、根干重、叶片数、茎粗、节长、节数、根冠比和根条数受品种影响显著(p<0.05),其余性状受品种影响不显著;3种不同外植体处理对马铃薯的根鲜重、苗干重、根干重、株高、茎粗、节数、叶面积和根冠比有显著性影响(p<0.05),其余性状受3种外植体的影响不显著。其中,以一个节段转接最有利于马铃薯脱毒试管苗的生长。 相似文献
16.
Computational fluid dynamics is used to simulate the hydraulic efficiency of the ozone contactor in A water plant in Beijing and to optimize the contactor by calculating the retention time distribution (RTD) of the fluid. The result shows that the value of T10 /HRT of the existing contactor is 0.466, and the phenomenon of obvious short circuiting and backflow which result in low hydraulic efficiency exists in the contactor. After optimization, the value of T10 /HRT of the contactor in the presence of guide plates is 0.561, making the hydraulic efficiency increased by 20.38%. However, the value of T90 /HRT is 1.316, which means that the phenomenon of backflow existed. The value of T10 /HRT of the contactor in the presence of horizontal baffles is 0.540, making the hydraulic efficiency increased by 15.88%, and the value of T90 /HRT reduces to 0.821. That means the concentration ratio of RTD increased, and the hydraulic efficiency of whole flow field is improved significantly in the presence of horizontal baffles. 相似文献
17.
利用EMS化学诱变高粱无融合生殖系的研究 总被引：2，自引：2，他引：0
使用浓度为0.3%的甲基磺酸乙酯（EMS）处理高粱无融合生殖系1094和2083的种子。4叶期将其幼苗移栽至大田试验地。目的是为了研究EMS对2个高粱无融合生殖系的影响,并选择变异株创新种质。结果表明,经过EMS化学诱变处理后,2个高粱无融合生殖系都出现不同程度的变异。M0代田间鉴定得到了株高、穗长、育性及结实率等突变体。两年平均株高、穗长、育性的变异率分别是0.66%、1.03%和1.93%,结实率以30%~40%分布的突变株为最多。因此,该技术在育种实践和理论上具有重要意义。 相似文献
18.
用闭合三角形杂交群体检测QTL等位位点差异 总被引：1，自引：0，他引：1
本文简述QTL定位和数量性状分子标记辅助选择的基本原理、基本方法,以及在实际应用中存在的一些问题。将12个不同作图群体构建的刚UP或SSR分子标记连锁图,根据其大多数分子标记所在的染色体节,再按每条染色体在各自连锁图中的相对长度整合在一起,然后将所定位的玉米株高QTL转换成整合图上的相对位置。结果发现,12个作图群体定位的75个玉米株高QTL位点遍布整个染色体组,QTL定位的重演性不高。分析认为,这是数量性状受众多微效多基因控制的必然现象。最后,提出用闭合三角形杂交群体进行QTL定位,检测QTL等位点的多重差异,并设想用这种方法验证或提高不同作图群体定位同一数量性状QTL的重演性。 相似文献
19.
The aim is to evaluate the seismic properties of ancient timber structure after strengthening and analyze the failure process and corresponding failure state. Based on the hysteretic behavior and energy dissipation principle of the dovetail column-frame strengthened with CFRP and Arches Brackets under the low reversed cyclic loading, the “potential of destruction-resisting” of the two energy-consuming components is obtained. The dissipated energy of each energy-consuming component under the various earthquake conditions is calculated combining with the shaking table test of ancient timber structure. The model of seismic damage evaluation of the two energy-consuming components is established on the basis of the “potential of destruction-resisting” and the dissipated energy. By means of the energy distribution coefficient, the relationship of the failure state between energy-consuming components and overall strengthened structure is discovered, and the model of seismic damage evaluation of the overall structure under the various earthquake conditions is presented. With the derived model of seismic damage evaluation, the failure coefficient of the energy-consuming components and the overall strengthened structure is quantitatively calculated. According to the failure state, the corresponding damage grade of overall strengthened structure is obtained. The results can provide a reliable theoretical basis for predicting the destruction before earthquake and re-reinforcement to the strengthened ancient timber structures after earthquake. 相似文献
20.
磁场处理对紫苏种子萌发的影响 总被引：1，自引：1，他引：1
试验采用20.9mT和42.5mT两个剂量的磁场对紫苏种子进行处理,处理时间分别为0h、1h、2h、3h、4h、5h。结果表明：20.9mT磁场强度处理紫苏种子,处理3h时发芽率最高,可达89%;在42.5mT磁场强度处理下,不同处理时间内种子发芽率均达到90%以上,远远高于对照,说明42.5 mT磁场强度处理紫苏种子有利于种子萌发;在42.5mT的磁场强度下,3h的磁场处理对株高、根长和须根数的增加都有明显促进作用;POD和硝酸还原酶活性在3h时相对增幅最大,说明42.5mT的磁场强度处理紫苏种子时,3h为最佳处理时间。 相似文献