Characters of Surface Deformation and Surface Wave in Thermal Capillary Convection

In the field of fluid mechanics, free surface phenomena is one of the most important physical processes. In the present research work, the surface deformation and surface wave caused by temperature difference of sidewalls in a rectangular cavity have been investigated. The horizontal cross-section of the container is 52 mmx42 mm, and there is a silicon oil layer of height 3.5 mm in the experimental cavity. Temperature difference between the two side walls of the cavity is increased gradually, and the flow on the liquid layer will develop from stable convection to un-stable convection. An optical diagnostic system consisting of a modified Michelson interferometer and image processor has been developed for study of the surface deformation and surface wave of thermal capillary convection. The Fourier transformation method is used to interferometer fringe analysis. The quantitative results of surface deformation and surface wave have been calculated from a serial of the interference fringe patterns.The characters of surface deformation and surface wave have been obtained. They are related with temperature gradient and surface tension. Surface deformation is fluctuant with time, which shows the character of surface wave. The cycle period of the wave is 4.8 s, and the amplitudes are from 0 to 0.55 mu m. The phase of the wave near the cool side of the cavity is opposite and correlative to that near the hot side. The present experiment proves that the surface wave of thermal capillary convection exists on liquid free surface, and it is wrapped in surface deformation.

燃油锅炉燃烧乳化重油的运行效果

燃油锅炉燃烧乳化重油有一定的节油效果。本文介绍了乳化油的制备及掺水方法，分析了乳化油蒸发、燃烧过程及其节油机理。

Characterizing Particle Dispersion by Image Analysis in ICFB

A new particle image technique was developed to analyze the dispersion of tracer particles in an internally circulating fluidized bed (ICFB). The movement course and the concentration distribution of tracer particles in the bed were imaged and the degree of inhomogeneity of tracer particles was analyzed. The lateral and axial dispersion coefficients of particles were calculated for various zones in ICFB. Results indicate that the lateral diffusion coefficient in the fluidized bed with uneven air distribution is significantly higher than that in uniform bubbling beds with even air distribution. The dispersion coefficients are different along bed length and height.

Investigation of High-Speed Combustible Gas Ignited by a Hot Gas Jet Produced in the Shock Tube

The high-speed combustible gas ignited by a hot gas jet, which is induced by shock focusing, was experimentally investigated. By use of the separation mode of shock tube, the test section of a single shock tube is split into two parts, which provide the high-speed flow of combustible gas and pilot flame of hot gas jet, respectively. In the interface of two parts of test sections the flame of jet was formed and spread to the high-speed combustible gas. Two kinds of the ignitions, 3-D “line-flame ignition” and 2-D “plane-flame ignition”, were investigated. In the condition of 3-D “lineflame ignition” of combustion, thicker hot gas jet than pure air jet, was observed in schlieren photos. In the condition of 2-D “plane-flame ignition” of combustion, the delay time of ignition and the angle of flame front in schlieren photos were measured, from which the velocity of flame propagation in the high-speed combustible gas is estimated in the range of 30–90 m/s and the delay time of ignition is estimated in the range of 0.12–0.29 ms.

Marangoni-Benard instability with the exchange of evaporation at liquid-vapour interface

A new two-sided model rather than the one-sided model in previous works is put forward. The linear instability analysis is performed on the Marangoni-Benard convection in the two-layer system with an evaporation interface. We define a new evaporation Biot number which is different from that in the one-sided model, and obtain the curves of critical Marangoni number versus wavenumber. The influence of evaporation velocity and Biot number on the system is discussed and a new phenomenon uninterpreted before is now explained from our numerical results.

流向微槽对涡轮叶片冷却通道内流动及换热特性的影响分析

在综合流向微槽表面流动及传热特性的基础上，结合涡轮叶冷却通道内的流动和换热特性，提出了将流向微槽表面应用于涡轮叶片的冷却通道，分析研究流向微槽的影响，以期为涡轮叶片的冷却寻找更有效的技术。

扩压段对高超声速推进风洞起动的影响

高超声速推进风洞是进行超燃冲压发动机模型地面模拟的重要试验设备.其中,扩压段的设计非常重要,它不是孤立的,而与主流系统和引射系统密切相关.通过对不同几何形状的扩压段在不同安装位置进行调试,研究在风洞起动过程中整个系统流动状态的演变规律,探索扩压段的优化设计.实验表明,扩压段应安装在距主喷管较近的位置,并具有与主喷管相匹配的入口面积和形状.扩压段的形状应设计成能使主气流通过一系列斜激波串减速的通道.扩压段应具有一定的长度以保证主气流减速到一定程度.

The Heterogeneous Growth of P(3MeTh)--An Ellipsometric Study

Successive thicker P(3MeTh) layers are analysed by ex situ conventional and imaging ellipsometry. Thin films display a smooth surface, are compact and homogeneous while for a growth charge above 20 mC cm(-2) the polymer structure modifies to a still uniform but less dense layer. A two-layer model is used and a mathematical procedure is developed to obtain, simultaneously, from the experimental ellipsometric parameters, Delta and Psi, the thickness and the complex refractive index of P(3MeTh) films grown up to 80 mC cm(-2). Thicker polymer layers are disordered and present a high degree of surface roughness. 

微尺度流动特性

通过微推进器小型化的具体问题说明微型化不是简单的尺寸缩小。微尺度流动所基于的物理因素与宏观流动不同，体现在流动涉及的表面积与体积之比增强、梯度参数效应及界面力效应等，物理因素作用的改变或新的因素参与，使微尺度流动呈现新的特点，这为设计芯片和传感器中的流动提供了新的思路，正如文中介绍的增强层流混合方法。微尺度效应在流体力学理论方面也会有所体现，包括对基本方程、边界条件的修正，然而对流动现象的深入认识则是理论发展的关键。简单介绍了作者的研究组在微尺度液体流动实验方面的研究结果。

Molecular Dynamics Modeling of Diffusion Bonding

Molecular dynamics simulations on diffusion bonding of Cu-Ag showed that the thickness of the interfacial region depended on the stress. The interfacial region became amorphous during diffusion bonding, and it would normally transform from amorphous into crystalline structure when the structure was cooled to the room temperature.

内旋流流化床换热埋管的传热特性

实验研究了内旋流流化床内水平埋管的对流换热系数，其特性与通常的流化床换热有很大差别。由于流动区较高速度的气流对于换热区的影响，在低于最佳流化速度的区间内，换热系数随流动区流化速度的上升而增加，曲线斜率下降。可以通过控制换热区的流化倍率来控制换热，对于维持适当的床温非常有利。在试验基础上，得出了内旋流化床埋管的换热系数关联式。

Hybrid Finite Compact-WENO Schemes for Shock Calculation

Hybrid finite compact (FC)-WENO schemes are proposed for shock calculations. The two sub-schemes (finite compact difference scheme and WENO scheme) are hybridized by means of the similar treatment as in ENO schemes. The hybrid schemes have the advantages of FC and WENO schemes. One is that they possess the merit of the finite compact difference scheme, which requires only bi-diagonal matrix inversion and can apply the known high-resolution flux to obtain high-performance numerical flux function; another is that they have the high-resolution property of WENO scheme for shock capturing. The numerical results show that FC-WENO schemes have better resolution properties than both FC-ENO schemes and WENO schemes. In addition, some comparisons of FC-ENO and artificial compression method (ACM) filter scheme of Yee et al. are also given.

Study on current-random wave forces acting on a framework

The forces of random wave plus current acting on a simplified offshore platform (jacket) model have been studied numerically and experimentally. The numerical results are in good agreement with experiments. The mean force can be approximated as a function of equivalent velocity parameter and the root-mean-square force as a function of equivalent significant wave height parameter.

等离子体喷涂涂层细观结构与工艺相关性研究

采用改进的颗粒沉积模型和一种新建议的循环算法，利用数值方法模拟了等离子体喷涂中涂层的生长过程及涂层的细观结构。数值模拟，主要包括了陶瓷液滴的高速变形与凝固、涂层材料的堆积、涂层中细胞空洞的形成与温度场的迭代计算等过程。研究结果表明，涂层中孔隙率的分布与一些关键工艺参数和基底表面状态等有关，液态陶瓷颗粒的直径和飞行速度的加大会引起涂层内孔隙率的增加，而基体温度和表面粗糙度的升高则有利于提高涂层的致密度。本文的研究结果将有助于定量或半定量地优化选取工艺参数以便获得所需的涂层结构和改善涂层的力学性能。