A first experimental study on two-phase how patterns at a long-term, steady microgravity condition was conducted on board the Russian Space Station 'MIR' in August 1999. Carbogal and air are used as the liquid...A first experimental study on two-phase how patterns at a long-term, steady microgravity condition was conducted on board the Russian Space Station 'MIR' in August 1999. Carbogal and air are used as the liquid and the gas phase, respectively. Bubble, slug, slug-annular transitional, and annular hows are observed. A new region of annular how with lower liquid superficial velocity is discovered, and the region of the slug-annular transitional flow is wider than that observed by experiments on board the parabolic aircraft. The main patterns are bubble, slug-annular transitional and annular flows based on the experiments on board MIR space station. Some influences on the two-phase how patterns in the present experiments are discussed.展开更多
In 1999, the space experiments on the Marangoni convection and thermocapillary convection in a system of two immiscible liquid layers in microgravity environment were conducted on board the Chinese scientific satellit...In 1999, the space experiments on the Marangoni convection and thermocapillary convection in a system of two immiscible liquid layers in microgravity environment were conducted on board the Chinese scientific satellite SJ-5. A new system of two-layer liquids such as FC-70 liquid and paraffin was used successfully, with the paraffin melted in the space. Two different test-cells are subjected to a temperature gradient perpendicular or parallel to the interface to study the Marangoni convection and thermocapillary convection, respectively. The experimental data obtained in the first Chinese space experiment of fluid are presented. Two-dimensional numerical simulations of thermocapillary convections are carried out using SIMPLEC method .A reasonable agreement between the experimental investigation and the numerical results is obtained.展开更多
In this study, we simulated space flight of the nematode, Caenorhabditis elegans, on the ground and examined how it is affected by space radiation and G-forces. We simulated G-forces during launch in a gravity acceler...In this study, we simulated space flight of the nematode, Caenorhabditis elegans, on the ground and examined how it is affected by space radiation and G-forces. We simulated G-forces during launch in a gravity acceleration laboratory device in order to identify and isolate the effects of the G-forces. Following this, we irradiated C. elegans with accelerated protons (MC-50 Cyclotron) and gamma rays (iR 222 machine) at the same physical dose. We calculated the expected radiation dose according to Reitz [1] and simulation programs (NASA AP8MIN [2], NASA AE8MAX [2], and CREAM86 [3]) for 1 month (dose rate: 6 × 10-3 Gy;2.8 × 10-2 Gy), 6 months (dose rate: 36 × 10-3 Gy;16.8 × 10-2 Gy), and 2 years (dose rate: 144 × 10-3 Gy;67.2 × 10-2 Gy) of space flight. There have been several trials that aimed to take C. elegans into orbit on US space shuttle missions including a mission on the shuttle Columbia. In this study, we simulated longer duration space flights and performed a whole-genome microarray analysis to observe phenotype variations whereas most such experiments were carried out during short duration space flights and focused on mutations and genotypic variations. We expect that the results of this study will be useful to predict the effects of long-term exposure of space radiation on living organisms.展开更多
本文主要针对我国载人空间站高温材料科学实验系统的任务需求,完成了系统热控方案的设计,包括液冷板布置、电机驱动机构和真空室热设计。基于系统三维几何模型,应用Ther ma l Desktop软件建立了系统仿真模型,确定了实验系统在最恶劣工...本文主要针对我国载人空间站高温材料科学实验系统的任务需求,完成了系统热控方案的设计,包括液冷板布置、电机驱动机构和真空室热设计。基于系统三维几何模型,应用Ther ma l Desktop软件建立了系统仿真模型,确定了实验系统在最恶劣工况时的边界条件。仿真结果表明,真空室外壁、控制电机、丝杠、滑块及导轨的最高温度分别为36.3℃、44.3℃、47.3℃、49.6℃和46.1℃,均低于温度限制值,系统热控性能满足设计要求。展开更多
基金The project supported by the National Natural Science Foundation of China (19789201)the Ministry of Science and Technology of China (95-Yu-34)The Post-doctoral Science Foundation of China
文摘A first experimental study on two-phase how patterns at a long-term, steady microgravity condition was conducted on board the Russian Space Station 'MIR' in August 1999. Carbogal and air are used as the liquid and the gas phase, respectively. Bubble, slug, slug-annular transitional, and annular hows are observed. A new region of annular how with lower liquid superficial velocity is discovered, and the region of the slug-annular transitional flow is wider than that observed by experiments on board the parabolic aircraft. The main patterns are bubble, slug-annular transitional and annular flows based on the experiments on board MIR space station. Some influences on the two-phase how patterns in the present experiments are discussed.
基金This work was partly supported by the 95-yu-34 of the Department of Science and Technology and the National Natural Science Foundation of China (Grant No. 19789201) Q. S. Liu wishes to thank Prof. J. C. Legros and Dr. Ph.Gerios for their helpful discussi
文摘In 1999, the space experiments on the Marangoni convection and thermocapillary convection in a system of two immiscible liquid layers in microgravity environment were conducted on board the Chinese scientific satellite SJ-5. A new system of two-layer liquids such as FC-70 liquid and paraffin was used successfully, with the paraffin melted in the space. Two different test-cells are subjected to a temperature gradient perpendicular or parallel to the interface to study the Marangoni convection and thermocapillary convection, respectively. The experimental data obtained in the first Chinese space experiment of fluid are presented. Two-dimensional numerical simulations of thermocapillary convections are carried out using SIMPLEC method .A reasonable agreement between the experimental investigation and the numerical results is obtained.
文摘In this study, we simulated space flight of the nematode, Caenorhabditis elegans, on the ground and examined how it is affected by space radiation and G-forces. We simulated G-forces during launch in a gravity acceleration laboratory device in order to identify and isolate the effects of the G-forces. Following this, we irradiated C. elegans with accelerated protons (MC-50 Cyclotron) and gamma rays (iR 222 machine) at the same physical dose. We calculated the expected radiation dose according to Reitz [1] and simulation programs (NASA AP8MIN [2], NASA AE8MAX [2], and CREAM86 [3]) for 1 month (dose rate: 6 × 10-3 Gy;2.8 × 10-2 Gy), 6 months (dose rate: 36 × 10-3 Gy;16.8 × 10-2 Gy), and 2 years (dose rate: 144 × 10-3 Gy;67.2 × 10-2 Gy) of space flight. There have been several trials that aimed to take C. elegans into orbit on US space shuttle missions including a mission on the shuttle Columbia. In this study, we simulated longer duration space flights and performed a whole-genome microarray analysis to observe phenotype variations whereas most such experiments were carried out during short duration space flights and focused on mutations and genotypic variations. We expect that the results of this study will be useful to predict the effects of long-term exposure of space radiation on living organisms.
文摘本文主要针对我国载人空间站高温材料科学实验系统的任务需求,完成了系统热控方案的设计,包括液冷板布置、电机驱动机构和真空室热设计。基于系统三维几何模型,应用Ther ma l Desktop软件建立了系统仿真模型,确定了实验系统在最恶劣工况时的边界条件。仿真结果表明,真空室外壁、控制电机、丝杠、滑块及导轨的最高温度分别为36.3℃、44.3℃、47.3℃、49.6℃和46.1℃,均低于温度限制值,系统热控性能满足设计要求。
