直接式加热炉炉管表面腐蚀原因分析

对直接式原油加热炉进行大修解剖发现,加热炉对流炉管腐蚀严重,通过对对流炉管表面腐蚀产物成分及产生腐蚀的原因进行分析,指出高温燃烧条件下炉管表面发生强烈氧化和硫酸露点腐蚀是造成对流炉管表面腐蚀的主要原因,并提出了防止炉管腐蚀的改进措施,确保加热炉的安全运行。     

再论响沙粒径特征和风选程度的关系

在沙尘暴的大风天气下 ,在银肯响沙湾落沙坡有对流风的情况下进行取样 ,并对沙的机械组成进行了测定 ,通过与 2 0 0 0年实验数据的对比 ,探讨了在沙尘暴的大风天气下 ,中沙和细沙是响沙的主要组成部分 ,重点阐述了银肯响沙湾特殊地貌条件下 ,大风天气对沙粒粒径风选程度的影响     

成品油顺序输送二维和一维混油模型比较

管道成品油顺序输送导致混油的诸多因素中，最基本的是介质的散布行为，即对流与扩散。两油品间的混油过程就是二维对流扩散过程，即轴向伸展与径向扩散。而轴向伸展帅管流横截面上速度不均引起的，长向扩散则是由深度梯度引起的。由分析得知，雷诺数越高，由一维混油理论求得的结果直接近二维混油法庭是的数值解，即雷诺数越低，一维混油理论求得的误差越大，在层流状态下，一维混油理论几乎不能成立，因此，在顺序输送设计与运行中     

智能温控自然对流式电暖器应用分析

本文对对流式电暖器的应用进行调研，通过调研的详细数据，阐明了电暖器应用的优缺点。     

北海夏季一次强对流天气过程分析

[目的]分析北海夏季一次强对流天气过程。[方法]利用Micaps常规资料和北海单站站点资料、雷达资料,对2010年8月北海市的一次强对流天气过程分析。[结果]850和700 hPa在越南北部和北部湾沿海的气旋性低压环流有利孟湾西南气流的输送,为强降雨提供充足的水汽条件;弱冷空气和东南暖湿气流相互作用是此次强降雨过程的主要原因;强降雨的落区与水汽的辐合有关,东南—西北向的水汽通量散度场的维持有利桂南地区强降雨的的持续;在强降雨之前,北海站高低层正负涡度均突然加强,对对流的产生十分有利;此次强降雨过程垂直速度随高度的变化从开始就由正值转为负值,这个转折对强对流天气的产生有预示预警的作用。[结论]该研究为夏季广西沿海强对流天气预报提供理论依据。     

泄洪洞有压段衬砌混凝土温度应力洒水对流系数敏感性分析

采取洒水养护是地下工程施工中控制混凝土产生裂缝的一项重要措施。基于ANSYS有限元软件对溪洛渡水电站泄洪洞有压段建模计算,进行了不同洒水对流系数的取值对温度应力的敏感性分析以及不同的洒水对流系数对混凝土温控的影响分析。成果表明,在混凝土温控研究中,不同的洒水对流系数对温度应力影响显著;洒水对流系数越大,混凝土早期温降越快,同时,会产生较大的拉应力,早期抗裂安全系数偏低,对后期温控反而有利,计算结果可为地下工程衬砌混凝土防裂研究提供相应参考。     

台风派比安外围龙卷天气分析

0606号台风派比安于8月3日19：20在电白至阳西之间沿海地区登陆后,8月4日其外围云带引发的一系列威力超强的龙卷风分别袭击了高要金渡、三水白坭镇、清远石角镇、南海大沥等地,并给上述地区造成了严重的灾害。笔者使用天气图资料分析龙卷风形成的天气形势背景,结合散度、涡度、垂直速度、垂直风切变、k指数等物理量及卫星云图、多普勒雷达回波资料分析其环境场和云带、回波的演变过程。     

Causes of recurring drought patterns in Xinjiang, China

Xinjiang Uygur Autonomous Region of China, with its unique topography and geographical location receives very less precipitation in summer as compared with other parts of China. The region is a land locked where moisture is supplied only by westerly winds from Atlantic Ocean as the moisture coming from Indian Ocean is mostly blocked by the Himalayas Range and the Tibetan plateau. In such a scenario, Xinjiang faces severe drought conditions offering significant challenges to water management. In this paper, we analyzed the drought periods in Xinjiang and discussed the various factors that might have influenced precipitation over the past forty-four years. For this purpose, we defined three periods of consecutive four years for high and low precipitation intensities. The average observed precipitation was 1.05 mm/day and 0.7 mm/day in summer (June-July-August) for the Tianshan Mountain region and Junggar Basin of Xinjiang, respectively. The drought conditions indicated that high sea level pressure, wind divergence and low convection were the prominent features that caused the droughts, which often do not allow the condensation process to coagulate the tiny water droplets into relatively large raindrops reducing the amount of precipitation in the region. The period of 1983-1986 is the lowest precipitation interval indicating the severe drought in the western Xinjiang (i.e western Tianshan Mountain region), for which, less moisture availability, strong divergence and less convection could be the most influencing factors.     

Effect of Marangoni Number of Liquid on Marangoni Convection in Liquid Bridge

The physical and mathematical model of the Marangoni convection in liquid bridge with liquid encapsulation (or two immiscible coaxial liquid columns ) are established. A numerical simulation of the Marangoni convection in liquid bridge with liquid encapsulation is performed by employing vorticity-streamfunction method and the Alternative Direction Implicit scheme in finite difference. The distribution of temperature and flow in two liquid columns are then obtained. The influence law of Ma number of liquid encapsulation to the Marangoni convection in liquid bridge with liquid encapsulation is obtained.     

The Effect of Aspect Ratio on Natural Convection in a Cavity with Discrete Heaters at the Bottom and a Top Heat Sink

Numerical study is performed to analyse the influence of aspect ratio on the nat-ural convection of high Pr fluid in a cavity with five discrete heaters at the bottom and an isothermalheat snk at the top,The range of aspect ratio is from 0.082 to 0.333, Raw is 107 and Pr is 90.Inthe half of the eavity five independent flow cells seperated by zero stream lines can be observed atsmall aspect ratio,which gradually merge into a single flow when aspect ratio increases and finallybeeome a big cell at A = 0.333.The average nusselt number based on the cooling arca,Nuc,showsthe highest value at A=0.082.With the incrcase of A,Nuc decreases and arrives the lowest valuewhile A=0.138,then increases and reaches an extreme value as A=0.164.After that Nuc fluctu-ates with the variation of increasing rate of flow velocity.