The bridge quest thermocapillaryconvection – Beijing

"The bridge" quest thermocapillaryconvection – Beijing "Tiangong two" has accumulated experience for the space station mission, is China Aerospace history "the most busy" space laboratory. There are many experimental projects in the field of loading, and one of them is the first experimental study on the thermocapillary convection in liquid bridge under microgravity. The so-called liquid bridge is formed by the liquid bridge". And often seen in the life of the bridge is different, it is not the real meaning of the bridge, but to take the meaning of the connection between the two, liquid bridge is connected between the two solid surface of small liquid column. The surface tension exists between the liquid and the gas, so that the liquid bridge can be maintained, but under the condition of normal gravity, the surface tension is very small, and the size of the liquid bridge is very small, so it is difficult to meet the requirements of the experiment. In the space, the object is in the state of "floating", and the surface tension becomes larger, which can form a large liquid ball, and the large size liquid bridge is established. Most people are unfamiliar with thermocapillary convection, but they are familiar with buoyancy. In daily life, when the fluid is heated and expanded, it will go up, and when the fluid is cooled, it will sink, thus forming the natural convection. In microgravity environment, weightlessness leads to the disappearance of buoyancy and buoyancy convection. The "Tiangong two" thermocapillaryconvection in liquid bridge space experiment project director Kang Qi said that under microgravity under the action of thermocapillary convection phenomenon will replace buoyancy convection becomes the main form of natural convection. The thermocapillary convection phenomenon is a kind of wonderful physical process, "Tiangong two" thermocapillaryconvection in liquid bridge space experiment project deputy director Li designer section explained that the thermocapillary convection is a fluid associated with surface or interface thermal convection. It is well known that there is an interaction force between molecules on the interface of the fluid, that is, the surface tension. Therefore, when the temperature distribution on the fluid interface is not uniform, it will result in different positions, the size of the surface tension is different, thus forming the phenomenon of driving fluid flow, which is the phenomenon of thermocapillary convection. Thermocapillary convection is widely used in industrial production, especially in the growth of high quality crystals. Kang Qi said, in order to produce high quality semiconductor material, it will affect the buoyancy convection and thermocapillary convection of scientific control in the process of crystal growth, and the unique space microgravity environment will allow scientists to make in-depth analysis of the real process of thermocapillary convection. The liquid bridge as a typical thermocapillary flow system is the main method of crystal growth model — floating zone method, but also the main experimental Temple No. two, "the thermocapillary convection in liquid bridge space experiment project device. This set of thermocapillary convection in liquid bridge experiment box weighs 13 kilograms, developed more than 3 years after, through the layers of the ground test test in space, the experiment equipment can complete liquid injection, bridge, bridge, temperature control, temperature and image acquisition and transmission by controlling the operation of packing. Among them, the experimental fluid medium – silicone oil is stored in the liquid cylinder, through the high-precision PI traction motor相关的主题文章: