Fluid flow and heat transfer with nail dipping method in mould during continuous casting process

ABSTRACT

The character and cause of sliver defect on IF steel sheet surface are studied by means of SEM, unstable flow in mould could induce surface velocity and level fluctuations, leading to surface defects during continuous casting of steel. The nozzle clogging is a serious problem during the continuous casting of steel, due to its influence on the casting operations and products quality. In this study, the nail dipping method for measuring surface velocity and flow direction in molten steel were employed. The fluid flow in mould of whole casting sequence was investigated, especially during the nozzle clogging conditions. The results showed that when nozzle clogging occurred in the 7th heat, the flow velocities on R and L side of nozzle were 0.280 and 0.402?m/s, respectively. The surface defect ratio of hot-rolled and cold-rolled plates increases with the increase of heat flux deviation on both sides of the mould copper. The different clogging per cent on both sides of the nozzle will lead to asymmetry flow, the surface velocity is higher with the small clogging per cent side compared to that of relatively large per cent clogging side.     

Preserving global features of fluid animation from a single image using video examples

We synthesize animations from a single image by transferring fluid motion of a video example globally.Given a target image of a fluid scene,an alpha matte is required to extract the fluid region.Our method needs to adjust a user-specified video example for producing the fluid motion suitable for the extracted fluid region.Employing the fluid video database,the flow field of the target image is obtained by warping the optical flow of a video frame that has a visually similar scene to the target image according to their scene correspondences,which assigns fluid orientation and speed automatically.Results show that our method is successful in preserving large fluid features in the synthesized animations.In comparison to existing approaches,it is both possible and useful to utilize our method to create flow animations with higher quality.     

CFD analysis on the catalyst layer breakage failure of an SCR-DeNOx system for a 350 MW coal-fired power plant

Selective catalytic reduction as one of the secondary NO_x control technologies is widely used in industrial sources including coal-fired power plants and large boilers. The performance of an SCR-DeNO_x system is sensitive to the installment of its components such as turning vanes and hybrid grids. In this work, three-dimensional CFD simulations are carried out to analyze the breakage failure of an SCR-DeNO_x system for a certain 350 MW coal-fired power plant. Research results are consistent with the phenomena that occur in the industrial application. It reveals that the breakage failure in the industrial application is likely to be caused by the inappropriate installation of the turning vane 3 locating closest to the catalyst, especially the angle of the turning vane 3. The analysis further shows that the lifetime or the breakage of the catalyst layers depends highly on the gas velocity, the fly ash distribution and its particle velocity.     

Computational fluid dynamics (CFD) investigation of air flow and temperature distribution in a small scale bread-baking oven

Experimental and computational fluid dynamics (CFD) analyses of the thermal air flow distribution in a 3-zone small scale forced convection bread-baking oven are undertaken. Following industrial bread-making practise, the oven is controlled at different (constant) temperatures within each zone and a CFD model is developed and validated against experimental data collected within the oven. The CFD results demonstrate that careful selection of the flow model, together with implementation of realistic boundary conditions, give accurate temperature predictions throughout the oven. The CFD model is used to predict the flow and thermal fields within the oven and to show how key features, such as regions of recirculating flow, depend on the speeds of the impinging jets.     

Optimization of Mixing and Mass Transfer in In-line Multi-Jet Ozone Contactors Using Computational Fluid Dynamics

Typical ozone mixing and mass transfer calculations are lumped approaches based on ideal operating conditions and can misrepresent behavior in real-life installations. This article models the effect of local hydrodynamics and mixing on the overall mass transfer of ozone into water with the aid of multiphase computational fluid dynamics (CFD). CFD models were validated with measured data from a pipeline ozone contactor installation which was optimized for more rapid, uniform mixing and mass transfer. Results emphasize the sensitivity of mixing quality to nozzle placement, size, orientation and spacing relative to main pipeline diameter and flows.     

CFD and experimental investigation of the gas–liquid flow in the distributor of a compact heat exchanger

High performance of compact heat exchangers is conditioned by correct fluid distribution. This is especially true for gas–liquid heat exchangers where a uniform distribution is particularly delicate to obtain and where maldistribution entails significant performance deterioration. Several phenomena can lead to phase distribution problems: the fins may be subject to manufacturing defects or fouling, leading to shortcuts or dead zones. But the first source of maldistribution may be a poor distribution at the outlet of the entrance distributor. This distributor aims at mixing the phases and distributing them across the channels.     

Multi-objective optimization of internal combustion engine by means of 1D fluid-dynamic models

The definition of an efficient optimization methodology for internal combustion engine design using 1D fluid dynamic simulation models is presented. This work aims at discussing the fundamental numerical and fluid dynamic aspects which can lead to the definition of a best practice technique, depending on the complexity of the problem to be dealt with, on the number of design parameters, objective variables and constrains. For these reasons, both single-and multi-objective problems will be addressed, where the former are still of relevant interest (i.e. optimization of engine performances), while the latter have a much wider range of applications and are often characterized by conflicting objectives.     

四川非常规气田开发主要钻井技术及其应用效果

随着油气勘探开发难度不断加大,尤其是近年来非常规气田的开发,定向钻井成为钻井主流技术,如何有效控制钻井成本和保护环境并防止井下事故的发生成为作业者必须面对的问题。为此,自2010年以来,在荷兰皇家壳牌集团(中国)四川非常规气项目50余井次的钻井工作中,运用了旋转导向技术、新型钻井液配方、钻井液回收技术和固控配套技术,取得了快速、安全、环保的应用效果,其中DXXX井应用旋转导向钻井,实现完钻井深5 729 m,水平段长1 418 m,钻井周期105 d,同比螺杆钻水平井节约时间65 d,钻井工程创下了该区新纪录。尤其是针对不同地层特点,兼顾环保要求,成功研制和应用了新型钻井液配方、固控和钻屑处理技术,取得了较好的环保效果。结论认为,上述配套技术的应用对提高钻遇产层成功率、提高钻井速度、缩短钻井周期、控制钻井成本、获得更好的经济效益和社会效益,具有重要的保障作用。     

四川盆地高磨地区龙王庙组储层岩石流体概率识别技术

四川盆地高石梯—磨溪地区下寒武统龙王庙组气藏储层的岩性与流体性质地震识别难度较大,主要原因是不同岩性、不同流体性质地层的岩石物理参数往往存在着较大的重叠空间,由此增加了识别的不确定性与多解性。为破解上述难题,采用岩石流体概率识别技术进行了尝试。该方法首先依据岩石物理参数分析结果建立各种岩性、流体性质的概率分布函数,再根据联合求解来确定储层的岩性及流体性质的概率,以此开展岩性、流体性质识别。应用结果表明:较之于一般的叠前反演方法,该方法通过多弹性参数对的联合概率求解,既提高了对储层岩性、流体性质识别的精度,又为提高储层岩性、流体性质识别的可靠程度提供了量化依据,可以为油气藏勘探开发井位部署决策等提供更充足的量化参考指标和依据。