舰船尾流散射特性的研究

利用Mie理论计算了单个气泡和舰船尾流横截面内气泡群的体散射函数.计算结果表明尾流中心的后向散射高于尾流边缘的.舰船尾流横截面内气泡群的散射与气泡大小,气泡尺寸分布和尾流深度有关系;在散射角180°附近后向散射增强显著;在散射角60°～80°之间,气泡群的散射相对于相邻角度有所增强.     

外部扰动对TiO2-MDEA纳米流体吸收CO2影响的研究

采用"两步法"制备分散性良好的TiO2-MDEA纳米流体作为吸收剂,在鼓泡实验装置上进行CO2吸收实验.研究了纳米颗粒质量分数和粒径对纳米流体强化CO2吸收的影响,以及气体体积流量、电磁搅拌和超声振动3种外部扰动方式对强化效果的影响.结果表明:纳米流体主要通过阻止气泡聚并、增大有效反应面积来强化CO2吸收,并且强化效果...     

A COUPLING MODEL OF WATER FLOWS AND GAS FLOWS IN EXHAUSTED GAS BUBBLE ON MISSILE LAUNCHED UNDERWATER

The gas and water flows during an underwater missile launch are numerically studied. For the gas flow, the explicit difference scheme of Non-oscillation and Non-free-parameter Dissipation (NND) is utilized to solve the Euler equations for compressible fluids in the body-fitted coordinates. For the water flow, the Hess-Smith method is employed to solve the Laplace equation for the velocity potential of irrotational water flows based on the potential theory and the boundary element method. The hybrid Eulerian-Lagrangian formulation for the free boundary conditions is used to compute the changes of the free surface of the exhausted gas bubble in time stepping. On the free surface of the exhausted gas bubble, the matched conditions of both the normal velocities and pressures are satisfied. From the numerical simulation, it is found that the exhausted gas bubble grows more rapidly in the axial direction than in the radial direction and the bubble will shrink at its "neck" finally. Numerical results of the movement of the shock wave and the distribution of the Mach number and the gas pressure within the bubble were presented, which reveals that at some time, the gas flow in the Laval nozzle is subsonic and the gas pressure in the nozzle is very high. Influences of various initial missile velocities and chamber total pressures and water depths on both the time interval when the gas flow in the nozzle is subsonic and the peak of the gas pressure at the nozzle end were discussed. It was suggested that a reasonable adjustment of the chamber total pressure can improve the performance of the engine during the underwater launch of missiles.     

微纳米气泡处理印染退浆废水

采用微纳米气泡法处理淀粉浆模拟废水,探究温度、pH、作用时间对淀粉浆分解率及COD去除率的影响.结果表明:在无任何助剂、温度80℃、pH 9左右、时间40 min的条件下,淀粉浆分解率为35.9％,COD去除率为28.9％.     

45K冷镦钢冷镦成型开裂原因分析

45K冷镦钢在冷镦成型时部分螺钉头部发生开裂。鉴此,对冷镦开裂螺钉试样及拉拔钢丝分别进行化学成分、金相组织、电镜能谱(EDS)等理化性能分析。结果表明：材料近表面存在皮下气泡是冷镦成型开裂的主要原因。     

WL-03型精密气泡式水位计在大理水文自动测报系统中的应用

简述WL-03型精密气泡式水位计的工作原理、主要技术参数,并简要介绍该仪器在大理水文自动测报系统中的应用情况。通过对WL-03气泡水位计在东武邑、沙溪等水文站多年运用的资料进行分析,其水位测报、整编精度符合规范的要求。     

一炉三段直接炼铅泡沫渣原因分析及应用

针对一炉三段直接炼铅过程中控制不当可能引发泡沫渣事故的问题,对泡沫渣的形成原因以及相关影响因素进行分析,从而提出在生产过程中采取控制终渣硅酸度在1～1.5、控制合理熔池温度、稳定过渡操作、合理喷枪操作等措施,避免泡沫渣事故的发生。     

海洋环境中混凝土抗冻融循环试验研究

模拟海水盐溶液来研究海洋环境中混凝土的抗冻融循环性能.海水与淡水环境中混凝土冻融循环对比试验结果表明,海水加速高水胶比混凝土的腐蚀速度,主要表现为混凝土试件表面冻胀剥落,质量损失率增大.控制新拌混凝土含气量在6%±1%,同水胶比的普通混凝土和高性能混凝土抗冻耐久性相当.矿渣微粉的二次水化作用会降低硬化高性能混凝土的含气量,但气泡间隔系数仍低于200 μm.为满足混凝土在海洋环境中抗冻耐久性要求,在保证混凝土气泡间隔系数低于300 μm的同时,混凝土水胶比不宜大于0.40.     

淮河流域名泉知多少

淮河流域温泉众多,比较著名的有:汤泉池,位于河南省商城县城十几公里处的灌河边上,闻名遐迩。该泉出口水温八十五摄氏度,气泡滚滚,像开水沸腾,水质清澈透明,冬日蒸气弥漫。七十年代修建鲇鱼山水库时以温泉为库区,采取了保泉措施,在泉口修建保温提水塔,高出库水面,把泉水送到岸边浴池。在此洗浴,泉     

楔形流道内单气泡动力学行为特性研究

楔形流道是一个具有复杂物理边界的流场,对其内部气液两相流动特性的研究具有现实意义.该文首先对孔板流量计内掺混气泡的两相流体建立了数学模型,采用贴体坐标系同位网格下的SIMPLE算法解决了速度与压力的耦合问题,改进了贴体坐标下Level Set方法,并利用其对楔形孔板流量计内单气泡两相流场进行了模拟.针对不同Re数和不同We数时其内部流场的模拟结果进行了分析,得出流场内气泡形态及其流动特性的变化规律.