下雾

Based on the theory of large eddy simulation and the method of VOF , the initial breakup process of fuel liquid jet, which eject from the nozzle exit at the time scale of micro-second level, is investigated. The mechanism of primary atomization is analyzed, and the initial breakup model of liquid jet is presented. By modeling and numerical simulation of atomization for a diesel nozzle under the given conditions, the initial umbrella-like spray shapes are obtained, which fits better with the experimental results. Meanwhile, the droplets secondary breakup process, such as leeward RT breakup, dumbbell-like breakup and droplets coalescence, etc. are exhibited visually.

基于大涡模拟LES理论和VOF方法，考察了燃油喷雾初始时刻即时间尺度为微秒级的液柱破碎过程，分析了初始破碎的机理，给出了该时间尺度下液柱初始破碎过程的模型；通过对一特定条件下的柴油机喷油器的建模和喷雾过程的大涡数值模拟，获得了液柱初始时刻"伞状头部"的喷雾形态，所得计算结果与相应的试验数据符合较好；数值模拟还直观地展现了液滴背风RT破碎、哑铃型破碎以及液滴的聚集融合等液滴的二次雾化过程。

The main research work of this paper are focused on following areas:(1) Based on review of the theory and methods on measurements of particle fields, a new idea for obtaining particle size and velocity distribution within a spray through imaging the particle field with a laser light sheet was put forward;(2) A DPIV (Digital Particle Image Velocimetry) system, is fit for velocity measurements of low speed flows, was developed and expended to particle size distribution measurement;(3) An arithmetic for particle velocity field reconstruction was developed, and the velocity distribution of water mist was also obtained;(4) A software system for particle analysis, which based on image geometry emend, de-noise and image partition was developed, the parameters such as particle size distribution, mean diameter, number of particles, minimum and maximum diameter can be got with this system;(5) A water mist system was developed and its characteristics, such as droplet velocity, size distribution, number of droplets and spray cone angle under different conditions were obtained from experiments with PIVS;(6) The measurement results of water mist characteristics with PIVS were compared and analyzed with the simply simulated results, and in addition, in order to verify the accuracy of PIVS, some experiments were conducted with the standard particles, such as glass-ball with known mean diameter of 50μm and 115μm, metallic coated tracing particle with mean diameter of 12μm;(7) Some experimental studies on interaction of water mist with liquid pool fires were conducted.

本论文的主要工作包括以下几个方面：（1）在对粒子场测量的相关理论和具体方法进行综述分析的基础上，提出了通过采用激光片光对粒子场进行成像以获取其粒径和速度等参数分布的新思路；（2）研制了适宜于低速流动速度场测量的DPIV(Digital Particle Image Velocimetry)系统，并使其实现了对粒子场粒径分布的测量功能；（3）研制了基于粒子运动轨迹的速度场重建算法，获取了细水雾雾场的速度分布；（4）研制了基于几何校正、去噪、图象分割等图象处理方法的"粒度分析软件系统"，该系统既可分析给出粒子场的粒径分布直方图和平均粒径，还可给出粒子的数目以及最大、最小粒径等信息；（5）建立了一细水雾发生系统，并应用上述方法对不同压力条件下细水雾系统的雾场特性（如速度分布、雾滴粒径分布、雾滴的数目、喷雾张角以及雾化长度等）进行了实验测量研究；（6）对细水雾特性参数的PIVS测量结果与计算机简单模拟计算结果进行了定性比较分析，并利用平均粒径为50μm和115μm的玻璃球以及12μm的标准示踪粒子对PIVS系统的粒径和速度测量结果进行了实验验证，同时对其局限性进行了分析讨论；（7）对不同工况条件下细水雾与油池火相互作用的过程进行了模拟实验研究。

Working principle is the power that uses water pump to serve as loop and sparge, the one side in gush room or 3 form Shui Lian, sparge is formed inside gush fog chamber, the Qi Wu of the generation when spray paint or burnish or dir

工作元理是使用水泵作为循环与喷雾的前进力，在喷房的一边或者三面产生水濂，在喷雾房内产生喷雾，喷涂或者磨擦时型成的漆雾或者尘士，在强效抽风作用以及影晌下经过水濂时随水势到水池内，剩余的通过喷雾室重新冲冼由排风机抽走，进而使排到室外的空气air达到和实现最好的诘白作用，满意环境保护请求。

The microclimatic characteristics of the dew and fog formation on canopy layer within a tropical rain forest,dominated by \%Terminalia myriocarpa \% in Xishuangbanna were measured in the dry\|hot season.

对西双版纳热带雨林干季林冠层雾露形成的小气候特征进行了观测研究。结果表明，雾露首先形成于最上林冠层，林下露水的形成迟于林上 3～ 4 h，林下雾是由上层雾变浓、下沉而来。

The effects of the spray-drying process of the ammonium paratungstate and the carburization temperature on the formation of the precusor and WC powder were investigated.

采用喷雾干燥-固定床法制备碳化钨粉末，研究了喷雾干燥和碳化反应温度对制备偏钨酸铵前驱体以及碳化钨的影响，前驱体粉末呈现均匀的球状形态，平均粒径为10~20μm，喷雾温度对影响粒径大小和分布影响小；400℃的进口温度下进行喷雾干燥，喷雾粉末仍然保持偏钨酸铵原来的基本组成不发生分解。

It is not raining , it is only misting.

没下雨，只是下雾了。

Since ventilation and evaporative cooling are the primary means for temperature adjustment in the duck house, a relationship for the traveling distance of water particles under various thermal environment was first established. This allows for the evaluation of efficiency of foggers for evaporative cooling. The relationship was then incorporated into a mathematical model based on the energy and mass conservation principle to simulate the transient change of outdoor temperature and humidity.

由於通风与喷雾降温为调节半开放式鸭舍内温度的主要方法，首先我们推导出雾粒在完全蒸发前移动距离与热环境条件的方程式，以计算於不同热环境条件下，不同大小雾粒的蒸发比率，从而评估喷雾降温的效率；次而利用质能平衡原理建立鸭舍内喷雾降温热环境模式，以计算及预测鸭舍内受外界热环境影响而产生的温湿度变化。

Therefore, by comparing particle distribution of the spraying under different water pressure, and the nozzle's outlet velocity simulation get by Ansys, which is a software for mechanical simulation, a proposal of the application of 1.5mm nozzle, 8Mpa water pressure on the spot was put forward.

在比较多种光学测粒仪的基础上，选择Winner313系统测量不同孔径喷嘴在不同供水压力下喷雾雾场的粒径分布。通过分析比较喷嘴在不同压力下喷雾雾场的粒径分布和Ansys模拟得到的喷嘴内部及出水口速度场，建议现场应用1.5mm喷嘴、供水压力为8MPa进行喷雾。

Under spraying humidification state, the parameters of JYPW-1 spraying axial fans for textile enterprises such as flow, total pressure, efficiency, shaft power and acoustic power level changing with water-air ratio were tested, and the performance parameter curve changing with water-air ratio was obtained. The approximate formula of its pneumatic performance in different water-air ratio condition were deduced which can be referenced for of selection and project application.

在喷雾加湿工况下，对纺织空调系统所用的JYPW-1型喷雾轴流通风机的流量、全压、全压效率、轴功率和比A声级噪声等性能参数随喷淋水气比的变化进行了测试，得到了喷雾风机性能参数随水气比变化的曲线，并整理出喷雾风机在不同水气比时，其气动性能的近似计算公式，可供喷雾风机选型和工程应用时参考。

It's wet, and the postponements are lining up.

最近总是下雾，很多比赛被延期。

Neither the killing of Mr Zarqawi nor any breakthrough on the political front will stop the insurgency and the fratricidal murders in their tracks.

在对危险的南部地区访问时，他斥责什叶派民兵领导人对中央集权的挑衅行为。

In fact,I've got him on the satellite mobile right now.

实际上 我们已接通卫星可视电话了