查询词典 jet flow

To accelerate the widespread of Synchronous Chip Seal and improve the operation quality of Synchronous Chipsealer, key techniques which influence the operation quality is studied detailedly, including the control of distributing quality, the dynamics characteristics of hydraulic system and the spray characteristics of asphalt nozzle of Synchronous Chipsealer.1 The factors which influence Synchronous Chip Seal quality are studied. Fiducial probability of simultaneous distribution density is advised to be used in evaluating the distribution bias and standard deviation of asphalt and aggregates simultaneously, which is more advanced than the single index evaluation method used before.2 The volume efficiency formula of asphalt pump is revised after analyzing the data of volume efficiency with mathematical statistics, which is helpful to match the asphalt spray system and control the flow out of asphalt pump accurately. With equation deduction and experiment, dynamic of hydraulic system used in Synchronous Chipsealer is studied, which lay the theory foundation on improving the stability and efficiency from design and controlling.4 Simulation on hydraulic system used in Synchronous Chipsealer is done with AMESim; the results indicate that multi-circle parallel connected hydraulic system with constant pressure power is better than that with load-sensing pressure power at present, because the latter will oscillate when the multi circles work at the same time. This conclusion has been proved during the debug of Synchronous Chipsealer.5 Asphalt nozzle characteristics, such as flat jet shape, flow distribution, are studied with experiment, the results indicate that cross quality of asphalt distributing is not increased linearly follow the increase of fan overlap level, the best point usually exists between two whole overlap level, asphalt distributing quality is better than±4% at the 2.5 overlap level, meets the superior specified in standard; The distribution quality of Synchronous Chipsealer can be increased by spray asphalt of different flow rang with nozzle of different diameter

为了加快同步碎石封层技术的推广，提高同步碎石封层设备的作业质量，本文对同步碎石封层设备作业质量的影响因素与控制方法、液压系统的动力学特性和沥青喷嘴的喷洒特性等关键技术进行了深入细致的研究：1研究了影响同步碎石封层作业质量的因素，提出了采用联合密度分布置信概率对同步碎石封层中沥青洒布量和碎石撒布量的系统偏差和标准差指标进行综合评价的方法，克服了传统评价方法只能对单一指标进行评价的缺陷；2采用数理统计的方法，研究了沥青泵的容积效率特性，修正了沥青泵容积效率公式，为沥青喷洒系统的匹配和沥青泵出口流量的精确控制提供了依据；采用数理方程推导与试验相结合的方法，研究了同步碎石封层设备液压系统的动力学特性，为从设计和控制的角度提高同步碎石封层设备液压系统的稳定性和效率奠定了理论基础；3运用AMESim软件对采用负载敏感控制和恒压控制的两种同步碎石封层设备液压系统进行仿真，结果表明：负载敏感控制的并联液压系统在多回路同时工作时，由于液压泵排量控制参考压力不稳定，容易引发液压系统振荡，恒压控制的并联液压系统是目前技术条件下比较理想的同步碎石封层设备工作装置驱动方案；该结论亦通过同步碎石封层设备装机试验得到了验证。4采用试验的方法对沥青喷嘴的喷洒特性进行了研究，结果表明：沥青洒布的横向精度并不是随着喷洒扇面重叠度的增加线性增加，其最高点通常出现在二个重叠度之间的"半重叠位置"，"2.5重叠"洒布时，沥青的横向洒布精度≤±4%，可以达到国家相关标准中的优级标准；同步碎石封层设备还可以根据不同洒布量情况下的流量需求，采用不同通径的喷嘴进行喷洒，提高沥青洒布精度。

The flow field of free jet was measured by PIV. The instantaneous velocity vectors of the core region of jet was studied experimentally.

利用PIV技术测量了射流流场，得到了自由射流核心区的瞬时速度场，并对实验结果进行了分析总结。

Methods:43 patients including 10 with mitral stenosis associated aortic regurgitation, 12 with mixed mitral valve lesions and 21 with mixed mitral valve lesions and combined with aortic regurgitation were studied.MVA determinded by (1) two -dimensional echocardiography with a cross-sectional area in the short-axis view (2DE),(2) pressure half-time using formula of 220/PHT,(3) color Doppler flow imaging with a jet cross-sectional area in the short-axis view with planimetry,(4) CDFI with a color jet width at the mitral valve orifice in the apical four-chamber view and long-axis view, assuming an elliptic mitral orifice, compared with the orifice area of excised mitral valve during mitral valve replacement.

材料与方法∶分别用二维超声(2DE)、压差减半时间、彩色多普勒二尖瓣口血流截面积和椭圆形面积法测定43例风湿性心脏病二尖瓣狭窄拟行人工瓣置换术患者的MVA，其中合并主动脉瓣反流 10例，合并二尖瓣反流 12例， 21例，并与手术标本的实测面积相比较。

The flow parameters such as the adhesion-wall effect of jet, penetration proportionlity of jet, momentum ratio, Reynold's number and incorporation time, which affect the mixing quality were analysed.

探讨了射流的流动状态如射流的附壁效应、穿透率、动量比及雷诺数等对混合的影响，并对混合时间进行了分析。

Secondly, projectile flow and interaction flow field between base jet and flow around body are firstly calculated by higher-order implicit TVD algorithm finite volume in china, and are compared with experiment data and shadowgraph, and are found to be in good agreement.

其次，利用我们建立的高阶有限体积隐式TVD格式，在国内首次较详细地求解了旋成体弹丸及其绕流与射流相互干扰的湍流流场，同相应的实验数据及其流场纹阴照片进行了对比，表明计算结果准确反应了实际流场性质。

Through topological analysis, draw out the topological characteristic of near field in slot jet: the amount, connecting forms of critical point and primary bifurcation, it have the same topological characteristic with round jet in despite of they have a different flow forms.

我们发现虽然有限长窄缝射流与圆孔射流在流动情况上存在一定差异，但它们近区流场的拓扑性质却是一致的。

Cold flow field in the precombustion chamber applying nonsymmetrical jets was investigated by numerical means. Conditions favorable for CWS ignition and combustion were analyzed. Optimal geometry and operation conditions of precombustor were presented for multistage nozzle jet and internal-mixing nozzle jet, respectively.

对本实验室发展的水煤浆偏置射流预燃室进行了用水煤浆燃料时两相冷态流场的数值模拟，探讨了适合于水煤浆点火和稳燃的条件，并通过大量的计算，分别初步优选出适合于多级气动喷嘴雾炬以及ZN型喷嘴雾炬的较好预燃室结构和操作工况。

This study found that pump jet's inflow velocity affect all flow field when in shallow water; pump-jet almost avoids tangling problem;rim-driven propellers can easily clean tangled material by reversing operation or different speed, and can still operate even when ropelike material stuck with the blades.

研究结果发现：在模拟泵喷推进器出入口方面，入口流速只在浅水时对整个流场影响较大。

This paper researches the jet pump performance in the water supply of hydropower station technology,through numerical value calculation to determine the geometric size of the flow components,and ensure the efficiency to be the highest value,and Derives the expression for efficiency and performance,protracts operating characteristics of jet pump and efficiency feature curve under different area.

本文针对水电站技术供水中的射流泵进行性能研究，通过数值计算，确定各过流部件的几何尺寸，以保障效率达到最高值。

Results indicate that the height of maximum horizontal wind velocity is correlative with the horizontal position. The downburst intensity and jet diameter have rather small effects on the test results in a certain range. Nevertheless, the jet height and obliquity can affect the flow field of downburst significantly.

研究结果表明：最大水平风速出现的高度与其水平位置有关；射流速度V与射流直径D在一定范围内对试验结果影响不大；射流高度h与入射倾角α对冲击风的流场有明显影响。

Cynanchum Lingtai apricot production in the average weight 65 grams, the brightly-colored fruit, juicy rich, sweet-sour taste, sweet from the nucleolus, when the late Qing Dynasty famous Shaanxi, Gansu provinces, the Qing imperial court Tongzhi tribute for years.

灵台生产的牛心杏平均单果重65克，果实色泽鲜艳，汁多味浓，甜酸适口，离核仁甜，清末时就驰名陕、甘两省，清同治年间曾为朝廷贡品。

Chenopodium album,Solanum nigrum, and Amaranthus retroflexus were very susceptible to the herbicides. Polygonum persicaria and Abutilon theophrasti were relatively less susceptible to the herbicides, and Lycopersicon esculentum was not susceptible to it. The relationship between reduction rates of weed biomass and PPM values of weed leaves 2,4, and 6 days after treatment was established.

供试的6种杂草对该混剂的敏感性存在显著差异：红心藜Chenopodium album、龙葵Solanum nigrum和反枝苋Amaranthus retroflexus对该混剂最敏感，ED90值分别为47.65、71.67和29.17g/hm2；春蓼Polygonum persicaria和苘麻Abutilon theophrasti敏感，ED90值分别为96.91、114.20g/hm2；而番茄不敏感。