共查询到18条相似文献,搜索用时 109 毫秒
1.
小孔持续周期性泄流的实验与观测 总被引:2,自引:1,他引:1
对小孔周期性泄流实验进行了研究,发现小孔周期性泄流的形成除了与实验装置内外筒液体的浓度、黏度和相容性有关外,还与内外筒之间的空隙有关;周期的大小不但与内外筒液体的浓度、小孔孔径有关,还与内外筒的直径有关. 相似文献
2.
3.
实验发现,激光束照射在振动的液面上,表面波对入射光可产生衍射;插入液体里的金属细丝被拉出液面时,由于液体的润湿效应,其周围的液体拉伸一定高度而断裂。以上两种实验现象机理,可用于液体表面张力系数的测定。激光经小孔透射样品池中的液体介质,在液体上表面发生遮光效应,根据其机理,建立了一种测量液体折射率的新方法。 相似文献
4.
5.
小孔周期性泄流的实验与分析 总被引:8,自引:2,他引:6
通过对小孔泄流的周期性研究.发现泄流周期随着时间进程变化趋于增大,小孔的直径越大泄流周期越小,不相容的液体间不能形成小孔周期性泄流,并分析了有关现象. 相似文献
6.
《中国光学与应用光学文摘》2006,(1)
TB962006010677用光学方法测量液体的物理参数=Optical measurement inphysical parameter of liquid[刊,中]/杨宗立(陕西师范大学物理学与信息技术学院.陕西,西安(710062)),苗润才∥光学技术.—2005,31(5).—729-731,735就液体表面声波对入射光波的衍射进行了研究。实验发现,激光束照射在振动的液面上,表面波对入射光可产生衍射;插入液体里的金属细丝被拉出液面时,由于液体的润湿效应,其周围的液体拉伸一定高度而断裂。以上两种实验现象机理可用于液体表面张力系数的测定。激光经小孔透射样品池中的液体介质,在液体上表面发生遮光效应,根… 相似文献
7.
8.
9.
关于“液体从器壁流出离壁距离”的讨论 总被引:1,自引:0,他引:1
一个装着液体的容器,侧壁开了小孔,液体由孔流出,落地处离壁的距离与什么有关呢?虽然这是一个简单的问题,但在某些书中却有着不同的答案。有的认为,小孔越高距离越远。就象灭火时,水龙头举得高,水就喷得远(图一)。有的则认为,小孔越低距离越远。因为“侧壁的压强随着液体深度的增加而增大”,所以,“最上面的离液面最近,即液体深度最小,压强最小,流出来的水喷得最近;中间的压强大一些,流出来的水喷得远一些;最下面的孔压强最大,流出来的水喷得最远。”(引号内摘自《数理化自学丛书第一册》见注一) (图二)。 上述两种结论都是错误的。 前种看… 相似文献
10.
浮顶罐中央排水管油气泄漏研究对及时制定合理的应急措施、预防重大事故发生有重要意义。介绍了一种判断中央排水管泄漏的方法。通过数值模拟分析了不同泄漏位置对中央排水管泄漏后报警时间的影响,模拟发现3个泄漏位置的报警时间最大相差1 308 s,说明泄漏位置对报警时间的影响较大。采用浓度为10%的甲烷代替油气进行了中央排水管油气泄漏激光检测可行性的实验验证。结果表明:TDLAS技术可用于中央排水管泄漏报警系统中油气浓度的检测, 对浮顶罐中央排水管泄漏报警系统的设计有一定的参考意义。 相似文献
11.
A phase-field model coupling with velocity field is employed to study the effect of boundary heat flux on the microstructure formation of a Ni-40.8%Cu alloy with liquid flow during the solidification, and an anti-trapping current is introduced to suppress the solute trapping due to the larger interface width used in simulations than a real solidifying material. The effect of the flow field coupling with boundary heat extractions on the microstructure formation as well as distributions of concentration and temperature fields are analyzed and discussed. The forced liquid flow can significantly affect the heat and solute diffusions, thus influencing morphology formation, concentration and temperature distributions during the solidification. The solute segregation and concentration diffusion are changed by boundary heat extractions, and the morphology, concentration and temperature distributions are significantly influenced by increasing the heat extraction, which relatively makes the effect of liquid flow constrained. By increasing the initial velocity of liquid flow, the lopsided rate of the primary dendrite arm is enlarged and the growth manner of dendrite arms gets changed, and the transition of the microstructure from dendrite to cellular moves to the large heat extraction direction. Therefore, there exists the competition between the heat flux, temperature gradient and forced liquid flow that finally determines the microstructure formation during directional solidification. 相似文献
12.
13.
本文采用去离子水和无水乙醇两种工质,利用微通道流动沸腾同步测量实验系统,研究了液膜厚度的瞬态变化规律,实验发现流动沸腾形成的初始液膜厚度在毛细数Ca很宽的范围内都遵循Taylor流动原理;液膜形成后,在蒸发和蒸汽流动携带的耦合作用下,厚度迅速减薄直至蒸干;由于水的汽液黏度比小,速度梯度小,剪切作用带来的液膜厚度减少量小,且水的汽化潜热大,吸收相同热量时蒸发量小,导致水的液膜厚度变化斜率较小,通过理论分析提出了沸腾液膜厚度变化的计算模型,计算结果与实验结果的误差小于20%。 相似文献
14.
15.
研究了带有圆孔的平板附近气泡动力学特性. 基于不可压缩势流理论, 建立了平板圆形破口附近气泡运动数值模型, 并针对气泡初始位置距离破口很近而导致计算结果发散的数值缺陷, 采用气泡壁和壁面融合的方法, 将流场分离为两个半无限域问题进行求解, 实现了在不同无量纲参数范围内的数值模拟, 数值结果与实验结果符合良好. 通过对圆孔附近气泡运动特性的研究发现, 圆孔对气泡的影响基本与壁面相反, 在膨胀阶段对气泡产生腔吸作用, 收缩阶段产生排斥, 在特定的工况下会产生对射流现象. 最后分析了气泡壁与壁面融合, 流场分离后的气泡动态特性以及各工况参数对其影响规律.
关键词:
气泡
边界元
射流
圆孔 相似文献
16.
R. Marx 《Zeitschrift für Physik B Condensed Matter》1981,41(3):189-194
A dislocation model for the shear viscosity of water is proposed, based upon the dislocation theory of melting and liquid state. This model, studied extensively within the last years in relation to phase transitions in two-dimensional systems, makes rigorous use of the similarity between the structure of a liquid and that of a crystalline solid. Viscous flow in water due to slip of dislocation loops is proposed as an alternative point of view to the hole theories and the cluster models of hydrogen bonded molecules. The model correctly yields the temperature dependence of the viscosity at normal pressure between melting and boiling point. 相似文献
17.
The viscose flow and microstructure formation of Fe-Cu peritectic alloy melts are investigated by analyzing the velocity and
temperature fields during rapid solidification, which is verified by rapid quenching experiments. It is found that a large
temperature gradient exists along the vertical direction of melt puddle, whereas there is no obvious temperature variation
in the tangent direction of roller surface. After being sprayed from a nozzle, the alloy melt changes the magnitude and direction
of its flow and velocity rapidly at a height of about 180 μm. The horizontal flow velocity increases rapidly, but the vertical
flow velocity decreases sharply. A thermal boundary layer with 160–300 μm in height and a momentum boundary layer with 160–240
μm in thickness are formed at the bottom of melt puddle, and the Reynolds number Re is in the range of 870 to 1070 in the
boundary layer. With the increase of Re number, the cooling rate increases linearly and the thickness of thermal boundary
layer increases monotonically. The thickness of momentum boundary layer decreases slowly at first, then rises slightly and
decreases sharply. If Re < 1024, the liquid flow has remarkable effects on the microstructure formation due to dominant momentum
transfer. The separated liquid phase is likely to form a fiber-like microstructure. If Re>1024, the heat transfer becomes
dominating and the liquid phase flow is suppressed, which results in the formation of fine and uniform equiaxed microstructures.
Supported by the National Natural Science Foundation of China (Grant Nos. 50121101 and 50395105) 相似文献
18.