离心机分离效果影响因素分析

大庆石化公司腈纶厂采用硫氰酸钠(NaSCN)溶液为溶剂生产腈纶纤维。通过离心机设备将蒸发后的NaSCN浓溶液进行较长时间的重力沉降,应用高速旋转的卧式沉降离心机分离出沉降槽底部堆积的Na2SO4,将Na2SO4外运处理。离心机的分离效果既影响NaSCN溶液的质量和产量,又涉及对环境的影响。良好的分离效果可使外运废料Na2SO4中的NaSCN含量较低、减轻NaSCN对环境的污染。1离心机的结构及工作原理离心机的结构见图1。离心机是根据NaSCN溶液和Na2SO4晶体的离心力不同,形成可分离的固液两相。固液分离发生在水平的圆柱     

Multiphysics simulation of a novel concept of MEMS-based solid propellant thruster for space propulsion

This work analyzes a novel MEMS-based architecture of submillimeter size thruster for the propulsion of small spacecrafts, addressing its preliminary characterization of performance. The architecture of microthruster comprises a setup of miniaturized channels surrounding the solid-propellant reservoir filled up with a high-energetic polymer. These channels guide the hot gases from the combustion region towards the nozzle entrance located at the opposite side of the thruster. Numerical simulations of the transient response of the combustion gases and wafer heating in thruster firings have been conducted with FLUENT under a multiphysics modelling that fully couples the gas and solid parts involved. The approach includes the gas-wafer and gas-polymer thermal exchange, burnback of the polymer with a simplified non-reacting gas pyrolysis model at its front, and a slip-model inside the nozzle portion to incorporate the effect of gas-surface and rarefaction onto the gas expansion. Besides, accurate characterization of thruster operation requires the inclusion of the receding front of the polymer and heat transfer in the moving gas-solid interfaces. The study stresses the improvement attained in thermal management by the inclusion of lateral micro-channels in the device. In particular, the temperature maps reveal the significant dependence of the thermal loss on the instantaneous surface of the reservoir wall exposed to the heat flux of hot gases. Specifically, the simulations stress the benefit of implementing such a pattern of micro-channels connecting the exit of the combustion reservoir with the nozzle. The results prove that hot gases flowing along the micro-channels exert a sealing action upon the heat flux at the reservoir wall and partly mitigate the overall thermal loss at the inner-wall vicinity during the burnback. The analysis shows that propellant decomposition rate is accelerated due to surface preheating and it suggests that a delay of the flame extinction into the reservoir is possible. The simulated operation of the thruster concept shows encouraging performance.     

In-tube rocket propulsion using repetitive laser pulses

In ’in-tube propulsion,’ that is the combination of conventional rocket propulsion and ballistic range operation,propulsion performance can be enhanced with increases in thrust due to spatial confinement and in payload capa-bility because propellant can be placed off board a projectile.This paper describes proofed concepts of in-tube propulsion by using repetitive laser pulses.     

法国鼓励发展生物燃料

法国推出生物燃料发展计划，力争使法国成为世界生物燃料大国。目前法国生物燃料主要是二酯和乙醇。二酯是一种从油菜、大豆或向日葵等植物中提取的物质，它被添加到粗柴油中后，可以成为很好的车用燃料。而利用甜菜、粮食、七豆等制取的乙醇，可以添加到汽油中去。     

Reconstruction of Ionization Density Distribution in Hall Thruster Channel from Ion Energy Spectrum of Plasma Jet

Propellant ionization in the Hall thruster discharge channel is a significant process and has strong influence on the thruster＇s efficiency. In this work, the functional relation has been established between the ionization density distribution and the function of the ion energy distribution through the basic equations governing the ion flow in the Hall thruster channel and the method achieved for reconstructing the ionization density distribution inside the channel by ordinary plasma diagnosis of the potential distribution and ion energy spectrum of the plasma jet. The ionization density distributions of single and double charged ions in an ATON-thruster channel have been reconstructed according to the experimental data of the potential distribution along the axis of the channel and the ion energy spectrum of the plasma jet. The agreement between the calculation and experimental results of the percentage of double charged ions proves the validity of our method achieved in this work.     

客滚船应用电力推进系统的可行性研究

客滚船是一种特种船舶，在保证安全和航速下，既要多装车辆又要改善乘客的舒适性。电力推进系统可以满足嗓音低、振动小、机动性好、机舱布置灵活、经济性好、可靠性高的要求。本文简要介绍了电力推进方式，并与柴油机推进进行比较评估。分析了客滚船采用电力推进方式的可行性、经济性等。依托在制的14000t客滚船提出了电力推进方案。     

面向海底光学探测使命的自治水下机器人水平路径跟随控制

针对利用光学探测设备对海底目标探测与搜索的使命,自治水下机器人（AUV）需具备更精确的航行控制性能,为此提出一种不依赖模型的改进型PID控制算法,通过对增设的左右水平推进器进行控制,以实现AUV低速时水平面的精确航行。将整个控制器分为两层：内层为偏航距离PID控制器,将输出量转化为所需偏转角;外层为航向PID控制器,将内层计算结果转化为航向偏差,对其进行PID计算,输出为偏转所需推力和推力矩值。通过对设定探测路线进行路径跟随,以反映水平面航行控制精度。通过湖上试验,得出精确的路径跟随航迹,实现了航向角偏差均值为0.09°、航向距离偏差均方差为0.29 m的航行稳定控制,验证了该控制方法的可行性。     

原汁机卧的好还是竖的好？苏泊尔SJYZ9—150VS九阳JYZ—E16

原汁机摒弃了金属刀网,并采用耐高温复合材料的慢速螺旋推进器方式,比传统榨汁机更完整保留食物中含有生命力的活营养素,彻底解决了出汁过程中果汁与金属接触发生氧化的问题,目前已经成为了很多榨汁机消费者购买的首选。市面上的原汁机产品种类繁多,其中又分为卧式和竖式两种,     

一种形状记忆合金丝驱动的仿乌贼水平鳍推进器

提出并实现了一种sMA丝驱动的仿乌贼水平鳍推进器.通过分析鳍的生理结构和波动规律,建立了仿乌贼水平鳍推进器的波动机构原理模型,提出了柔性鳍单元.然后设计了形状记忆合金丝驱动的、基于柔性鳍单元的无线电遥控仿乌贼水平鳍推进器,并对双侧10鳍单元的仿乌贼水平鳍推进器进行了游动试验.试验表明该推进器可以实现前进、后退、左右转功能,可以实现8 mm/s的游动速度和12°/s的转弯速度,它具有无噪声、无污染、驱动电压低、机动性好、结构简单容易密封等优点,其扁平身体结构能够进入狭窄复杂的水下区域进行探测.