Numerical Simulation of the Morphology and Moving Velocity for Electrospun Stable Jet

GAMBIT,POLYFLOW and FLUENT POST were used to simulate the morphology and the velocity of electrospun stable jet.Simulation results shows that jet diameter decreases with the increased draw force acted on the stable jet.But too great draw force would lead to thick knots appearing along the jet or stable jet disappearing during electrospinning.There is a linear relationship between the velocity and the moving distance.But the linear relationship does not exist under great draw force.     

垂直射流沿恒温热平面的热量传输和速度分布

研究了二维冷液体射流垂直冲击一个恒温热平面时，射流沿平面的热量传输和速度分布．通过对Ｃｒｏｃｃｏ变换加以推广，求得了问题的相似解，揭示了速度梯度，温度分布和剪切力之间的关系．     

超喂率对空气变形纱的成纱结构、性能及其织物的影响

超喂率是影响空气变形纱(以下简称空变纱)及其织物结构性能的一个重要参数。本文就超喂率对空变纱的形态结构、光泽、强伸度、摩擦等性能以及对空变纱织物性能的影响进行了较全面的实验研究,给出了实测数据,并通过分析而引出了重要结论。     

熔喷模头双缝形喷嘴纺丝线上的气流变化

通过引入喷嘴头端宽度与气缝宽度的比值这一参数，建立了熔喷双缝形喷嘴流场纺丝线上气流速度、温度变化的经验方程，是以往经验方程的进一步完善。使用该经验方程结合熔喷理论模型进行了纤维最终直径的预测，实际预测结果证明了所建经验方程的正确性和可靠性。     

Landfill leachate treatment by MBR： Performance and molecular weight distribution of organic contaminant

A membrane bioreactor (MBR) with an air-lift bioreactor and gravity flow is applied to treating landfill leachate. More than 99% of BOD5 (biochemical oxygen demand for five days) removal effi-ciency is achieved with less than 35 mg/L of BOD_5 in the effluent at less than 1.71 kg BOD5/m~3·d of BOD_5 loading rate. When DO (dissolved oxygen) is maintained at the range of 2.3―2.8 mg/L and the loading rate of NH_4~ -N (ammonium nitrogen) is kept at 0.16― 0.24 kg NH_4~ -N/m~3·d, the NH_4~ -N in the effluent is less than 15 mg/L. However, compared with high removal rates of BOD_5 and NH_4~ -N, the removal effi-ciency of soluble chemical oxygen demand (SCOD) varies between 70% and 96%. The investigation of molecular weight (MW) distribution has been carried out by the gel permeation chromatography (GPC) so as to understand the fate of organic matters in the MBR treating of landfill leachate. Results indicate that organic matters of the landfill leachate are composed of a high MW fraction (MW of the peak, MWp = 11480―13182 Da) and a low MW fraction (MWp = 158―275 Da). The high MW fraction is not biode-gradable, but can be decreased with microfiltration membrane. The most of the low MW fraction is bio-degradable, but the residue of the low MW fraction is able to permeate through the membrane, thus re-sulting in high SCOD in the effluent of the MBR.     

倾斜侧吹气流在液相中的轨迹

以动量定理为基础,建立了倾斜侧吹射流轴轨迹的数学模型。模型的主要特点是,对于侧吹倾斜射流,推导出无因次射流轴轨迹的微分方程。对于空气向水中喷吹,数值计算表明,本计算轨迹与实测射流的轴线一致。     

气流粉碎机用蒸汽加料器设计参数研究

对适用于气流粉碎机的蒸汽输送喷射器的设计理论及计算方法作了详细的研究，为气流粉碎机加料器的设计提供了有用的工具。     

地铁基坑止水帷幕摆喷桩施工技术

以广州地铁二号线琶洲站、琶洲折返线为例，介绍止水帷幕摆喷桩在基坑支护结构中的作用、施工方法及施工技术。     

稀土氯化物喷雾热解装置雾化效果的物理模拟

稀土氯化物雾化热解是稀土氧化物制备新工艺,但目前喷雾热解装备雾化效果差,雾化后液滴粒径分布不均匀.本文自行设计了文丘里管喷雾热解反应器,将粒子图像测速技术与MATLAB图像处理技术相结合,研究了气体流量、文丘里管和引流管几何尺寸等因素对雾化效果的影响.结果表明:文丘里管扩散段中较强的回流作用会加剧气液相间的混合碰撞,进一步破碎液滴;而过多的液相携带量容易导致雾滴密度变大,增大了液滴在运动过程中的碰撞几率,致使雾滴尺寸变大.文丘里管反应器适宜的几何尺寸和操作条件为:内径100mm,喉口内径10mm,引流管内径5mm,气相流量20.5m³/h.     

波流环境下多孔射流运动和稀释特性试验

采用PIV和PLIF技术对波流环境下多孔垂向射流近区的速度场和浓度场进行测量,对比分析不同波浪条件下射流运动轨迹、速度场、浓度场及涡量场特性,重点探讨波流和纯流环境下射流运动特性的差异以及波浪作用对多孔射流发展的影响。结果表明:波流流场中射流时均轨迹发生扭曲,产生"污染物云团"现象,与纯流环境下射流差异明显;波浪对波流环境下的多孔射流运动影响显著,具体表现在波浪强度的增大能够增加射流与环境水体的接触面积、加快射流垂向动量衰减、增强前方射流对后方射流的遮掩作用、降低多孔射流汇合点高度等方面。当前组次下,波浪的存在使得各断面污染物浓度峰值减小,因此对波流环境下多孔射流的稀释有积极的作用。