高浓度粘稠物料加压旋转流变仪的研制与标定

高浓度粘稠物料(如原生煤泥、造纸污泥等一类工业副产品或固体废弃物)流变特性的测定在其管道输送系统的设计中有重要意义。这种粘稠物料若无添加剂作用在常压下是一种分散结团物料,不具备流体特性,无法采用一般旋转流变仪对其流变特性进行测试。因此研制出一种新型加压旋转流变仪(最高压力20MPa),将物料封闭加压,维持管道输送时的工况,保持其流体形态,从而达到物料加压流变特性测试的目的。该仪器的标定与使用结果表明其达到了设计要求,数据采集方便,测量自动化程度较高。     

加压管式流变测试系统的设计

非牛顿流体流变特性复杂多样,测试原理有管流法、落球法、圆盘法、同轴旋转粘度计法等,相应的测试仪器也是多种多样.但针对同一种流动特性较差的非牛顿流体,若采用不同的方法和仪器进行测试,由于不同的测试状态被测流体的受力和运动状态不同,得出的流变特性及参数也是不同的.尤其是针对l丁业管道输送的流动性较差、流变特性又较难测试的非牛顿流体,如何准确测试被输送介质的流变特性,为管道工艺提供设计依据是亟待解决的问题.基于此,本文设计了加压管式流变测试系统,基于管流法的流变测试原理,通过氮气加压致使被测试物料流动,模拟管道输送的工况,测试流动性较差的非牛顿流体的流变特性,为管道工艺设计提供实验平台.     

Tracerco公司γ射线物位计在辽化PTA装置的应用

γ射线物位计多用于液体、固体、悬浮液和污泥的连续非接触测量．测量不受被测介质的化学性质和温度、压力、黏度等物理性质的影响,所需维护保养少,可长期连续使用。特别适用于密封容器内高温、高压、高黏度、强腐蚀性、剧毒、深冷物料的料位检测。γ射线的辐射强度将随着所通过物料厚度的增加而逐渐地减弱。射线辐射强度的变化遵循指数衰减规律：     

振动管式密度计在制糖生产中应用

１前言制糖工业生产离不开锤度、波美度测量，怎样才能实现准确地在线测量这是制糖工作者普遍关心的问题。锤度、波美度实际上都是物料浓度的一种度量，由于介质的浓度与其密度存在着一定的关系，因此，凡是测量密度的仪表都可以按锤度或波美度进行定标，成为测量制糖介质...     

天津市鑫成仪表厂

天津市鑫成仪表厂是生产液位测量、控制仪表的专业厂家。本着“团结,务实,创新,高效”的工厂方针,依靠自身的技术力量的良好的职工素质,使产品开发一年一个台阶。至今已拥有６大系列、近６０多种规格型号的液位、物料测量控制仪表,主要用于化工、电力、食品、轻工等工业部门的开口或密封、带压容器、锅炉等设备的液位物料介质进行测量、控制、报警或远传,并可在罐群使用远传装置与记录仪或计算机联网。 本厂在产品设计、开发、生产工艺、质量检验、安装调试、售后服务等方面技术能力雄厚,设备、工装卡具、测试仪器仪表齐全。生产的…     

天津市鑫成仪表厂

天津市鑫成仪表厂是生产液位测量、控制仪表的专业厂家。本着“团结,务实,创新,高效”的工厂方针,领先自身的技术力量的良好的职工素质,使产品开发一年一个台阶。至今已拥有６大系列、近６０多种规格型号的液位、物料测量控制仪表,主要用于化工、电力、食品、轻工等工业部门的开口或密封、带压容器、锅炉等设备的液位物料介质进行测量、控制、报警或远传,并可在罐群使用远传装置与记录仪或计算机联网。　　本厂在产品设计、开发、生产工艺、质量检验、安装调试、售后服务等方面技术能力雄厚,设备、工装卡具、测试仪器仪表齐全。生产…     

糜状食品物料流变特性测试系统的研制

糜状食品物料因为具有颗粒大、粘度高、非均质等特点,一般的粘度计都不适宜测量其流变特性。针对这个问题,研究开发了基于计算机控制的双筒双向间隙流变测试系统。本文阐述了该系统的测试原理及软硬件的组成和实现方法。由于本测试系统具有误差小,可靠性高等特点,因而解决了糜状食品物料在流变学研究分析和生产实际应用中进行流变测试的困难。     

新型污泥干燥装置的研发

研发了一种新型污泥干燥装置,主要介绍了新型干燥装置的结构型式,并以处理污泥为例,计算了干燥装置的物料和热量,设备尺寸等内容。解决了传统污泥干燥设备干燥效率低、出泥含水量高的瓶颈,为污水处理行业提供了一种高效简便的污泥干燥方式。     

一种双抓斗桥式起重机小车设计

为满足在垃圾焚烧发电领域,垃圾抓斗桥式起重机需要协同处理污泥等物料的要求,开发了一种配备有双抓斗的起重机小车,可对垃圾和污泥等物料进行交替抓取,文中对这种带有侧挂污泥抓斗的双抓斗桥式起重机小车开展了布置设计,并辅以理论计算,详细介绍了小车各主要参数的设计思路及方法,为同系列产品的开发奠定了设计基础.     

微波(雷达)物位计讲座

正(接2016年第6期)第三章微波物位计的天线微波物位计天线的功能是:向被测物料发射微波能量,并且接收从被测物料面反射的微波回波,以便用于电子组件分析、计算。用于物位测量的微波天线有六种基本类型:喇叭(圆锥形)天线介电棒天线透镜式天线测量管天线(稳定管、旁通管等)     

高粘度煤泥加压旋转流变仪的标定与应用

高粘度煤泥流变特性是影响其高压管道输送阻力的一个重要因素．故研制加压旋转流变仪测量高粘度煤泥不同压力时的流变特性。标定加压旋转流变仪,用于测试压力对流变性的影响。使用加压旋转流变仪测试浓度75％煤泥的剪切应力和剪切速率．绘制了煤泥不同压力时的流变曲线和表观粘度曲线,通过分析确定了煤泥常压下是宾汉型流体,加压下为屈服假塑性流体。     

Textile injection process characterisation by means of a spiral mould

New developments are being carried out within the injection moulding field, such as gas injection, bi-injection, co-injection, sequential injection, compression injection or textile injection processes. These techniques require new developments as they highly modify design and process conditions. In this work, the influence over the plastic material flow of the introduction of different film textiles into the mould is measured. A specific measurement system consisting of a monitorised spiral mould with pressure sensors has been used to measure the influence of different tissues over the mould pressures. As an application of this measurement system, a viscous model is generated to characterise the rheological behaviour of the thermoplastic and textile joint. The viscous model obtained is applied on a conventional CAE tool for the simulation of textile injection pressure results for the different film textiles analysed.     

粘稠物料管道输送实验系统的设计与测试方法

本文以管道输送煤泥到电厂锅炉燃烧发电为背景,开展对粘稠物料的流变学特性和管道输送特性的研究。根据煤泥的流变特性,设计建造了适合此类高浓度、高粘稠度的非牛顿流体管道输送实验系统。实验结果表明,该系统设计合理、功能完善、测试数据准确可靠,可用于粘稠物料工业输送测试和指导现场的工业管道优化设计与安装调试。     

Modeling and simulation of polymer melts flow in the extrusion process of plastic profile with metal insert

The extrusion technology of plastic profile with metal insert is recently an advanced plastic processing method whose products keeps rising today for their excellent performance. However, the related fundamental research on polymer forming mechanism in the extrusion process of plastic profile with metal insert is lagging behind. With the development of computational fluid dynamics (CFD) theory, numerical method becomes an effective way to investigate such complex material forming problems as in the polymer extrusion process. In the present study, the mathematical model for three-dimensional non-isothermal viscous flow of the polymer melts obeying a Carreau model is developed based on the CFD theory. The Williams–Landel–Ferry equation is employed to involve the temperature dependence of material parameters. A decoupled numerical algorithm based on the penalty finite element method is conducted to predict the rheological behaviors of polymer melts within the complex flow channel. The streamline upwind/Petrov–Galerkin scheme is employed to improve the computational stability for the calculation of temperature field. Based on the theoretical model, the essential flow characteristics of polymer melts in the extrusion process of plastic profile with metal insert is investigated. The distributions of principal field variables like flow velocity, melt temperature, flow stress and pressure drop are predicted. The effects of die structure parameters including the intake angle and the distribution section length upon the melts flow patterns are further discussed. The variations of melt rheological properties versus different processing conditions like the volume flow rate and the metal insert moving velocity are also investigated. Some advice on practical processing operations of the extrusion process of plastic profile with metal insert is accordingly put forward based on the numerical results.     

High pressure rheometer for in situ formation and characterization of methane hydrates

We present a novel setup for a high pressure rheometer operating with concentric cylinders geometry for in situ studies of hydrate formation and rheological characterization. The apparatus uses an external high pressure mixing cell to saturate water-in-oil emulsions with methane gas. The capability of mixing combined with a true rheometer design make this apparatus unique in terms of setup and sample formation. We have used the apparatus to form gas hydrates in situ from water-in-oil emulsions and characterize suspension rheological properties such as yield stress and shear-thinning behavior.     

Viscous dissipation influencing viscosity of polymer melt in micro channels

Determination of melt rheological behavior within micro-structured geometry is very important for the accurate simulation modeling of micro-molding. Yet studies on the rheological behavior of polymer melts, flowing through micro channels, are complicated due to a large number of factors affecting the melt viscosity. One factor, viscous dissipation, is investigated in the current work through a novel experimental technique to determine the viscous dissipation of a polymer melt flowing through several micro channels with identical aspect ratio. Relative tests are conducted with the melt of high density polyethylene (HDPE) at different temperatures being extruded through the capillary dies with diameters 1000μm, 500μm and 350μm, respectively. It was found that the temperature rise due to viscous dissipation decreases significantly with the reduction of the characteristic size of micro channel at the same shear rate. In addition, based on the suggested model of radial temperature distribution, the influence of viscous heating on the melt viscosity is investigated. The results indicate that viscous dissipation does not play a significant role.     

Some tribological and environmental aspects in metal drawing

The methods of soap powder lubrication in dry drawing of metals are compared with a novel solid film lubrication. Concerning powder lubrication the required lubricant carrier or conversion treatments of the forming material surface are also considered. Both the tribological as well as the environmental aspects indicate the high potential of solid film lubrication. By means of examples the problem of aqueous dispersion stability of calcium soap systems is dealt with, which is one of the main problems in developing suitable coating systems. After coating, the adhesive and rheological behaviour of the dried solid soap layers on the wire or rod surface enable an excellent hydrodynamic pressure to be built up during the drawing process. When using a double die pressure tool, the pressure development is substantially controlled by the inlet die. In applying the solid soap film lubrication some environmental advantages with respect to soap powder lubrication become obvious. Chemically aggressive substances, such as lubricant carriers and conversion chemicals or acid pickling solutions, can be minimized or even eliminated. Moreover, rinsing water pollution and lubricant dust are reduced.     

Evaluation of Thermal and Rheological Properties of Lubricating Greases Modified with Recycled LDPE

The influence that recycled low-density polyethylene (LDPE) and lithium thickener concentrations exerts on the thermal and rheological properties of lithium lubricating greases was investigated using different rheological techniques in a temperature range of 25–175°C. In this way, different lubricating grease formulations were manufactured by modifying the concentration of lithium 12-hydroxystearate and content of recycled LDPE. These lubricating greases were rheologically characterized through small-amplitude oscillatory shear (SAOS) and viscous flow measurements. In addition, bomb oxidation tests (BOTs) and thermogravimetric (TGA) analysis were carried out. From the experimental results obtained, it can be deduced that modified lithium lubricating greases can be considered thermo-rheologically complex materials. Different behaviors of the viscoelastic modulus with temperature as a function of thickener and recycled LDPE concentration were found. Two types of viscous flow behavior were observed depending on the grease composition: A plateau region appeared in a wide range of shear rates and, in some cases, a minimum in the flow curve was more pronounced at high temperatures. The modified lubricating greases studied showed lower thermal and oxidation stability than unmodified lithium lubricating greases.     

On the effect of shear-thinning rheology on hemodynamic characteristics in basilar tip aneurysms with implication of two distinct flow patterns

Intra-aneurysmal hemodynamics such as wall shear stress and complex flow structures have been implicated as one of the important factors on the growth and risk of rupture of an aneurysm. In this study, the sensitivity of intra-aneurysmal blood flow dynamics to the shear-thinning rheological model is investigated by using the idealized geometries of a basilar tip aneurysm with two representative anterior-posterior (AP) tilting angles (2° and 30°). By choice of different rheological models, time-averaged hemodynamic factors such as wall shear stress, oscillatory shear index and relative residence time exhibited only minor effects. However, highly unstable flow present in idealized aneurysm model with 2° AP tilting angle facilitated an evident change in the instantaneous local flow dynamics with a considerable increase in effective viscosity. Nevertheless, the distinct hemodynamic phenotype, which characterizes the gross intraaneurysmal flow pattern, was independent of the choice of rheological model. This result suggests that the shear thinning viscous effect is of secondary importance in the gross hemodynamics in a basilar tip aneurysm but is appreciably enhanced on the instantaneous hemodynamics with unstable complex flow structures.