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。     

高压智能旋转流变仪机械结构设计方案研究

给出高压智能旋转流变仪机械结构的设计方案,高压智能旋转流变仪能够在压力不超过35MPa的条件下测定各种流体的流变参数,为高浓度煤泥和其它物料管道输送实验台建立流变特性模型获得可靠的实验数据创造了条件.     

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.     

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。     

JYX高浓度黏稠物料加压旋转流变仪的研制

鉴于高浓度黏稠物料(如原生煤泥、城市污泥、造纸污泥等一类工业副产品或固体废弃物)若无添加剂作用在常压下是一种分散结团物质，流变参数测定过程中常出现被测介质“打滑”和容易“离析”等问题，研制出一种加压旋转流变仪(压力最高可达30MPa)，测量时将物料封闭加压，从而达到此类介质加压测量流变特性的目的。     

高浓度粘稠物料管道输送系统压力测试及其装置

高浓度粘稠物料存在于工业领域的各个行业,本文对高浓度粘稠物料的流变学特性和管道输送特性的研究出发,设计制造了适合此类非牛顿流体的管道输送压力测试装置.文中详细介绍了测压装置的结构组成、主要功能以及测试方法,并对该装置的静态标定和动态标定过程及其结果做了分析,通过对多种高浓度粘稠物料的实验测定,表明该测压装置安装位置合理、测试数据全面、测试精度和性能可靠、测压装置的结构紧凑、安装方便,完全适用于高浓度粘稠物料管道压力的测量.     

新型浓密膏体流变特性测试实验台研制与验证

非牛顿流体在管道输送时其流变特性是管道工艺设计的主要依据.基于管流法的流变测试原理,分析已有浓密膏体流变特性测试实验台优缺点,取长补短对其实施改进.采用液压系统代替气压方式推送物料实现管道输送,以"稳流量测压差"代替"定压力测流量"的方式获取关键参数,以此推算浓密膏体的流变特性,为浓密膏体的管道输送工艺设计提供新实验平台.以赤泥为例进行实验验证,确定了67.5%～68.5%浓度赤泥不同管径输送下的流变模型.测量过程表明本实验台可行且操作方便、数据可靠;原始实验数据及其处理结果符合理论规律.     

AR—G2型流变仪的特点及应用

AR—G2型流变仪是用于深入研究和材料研制的一种全新旋转流变仪,它经过五年的深入研发,对基本流变测量技术有创新和改善。AR—G2型流变仪仍然是唯一能为单纯的流变测量提供独特的独立马达和传感技术的商用流变仪,没有任何其它流变仪能够独立地应用剪切变形进行应力测量。粘度是流体的重要物理性质之一,其数值的准确与否对制定油气田开发对策具有重要意义。利用AR—G2型流变仪对西峡沟原油流变性能进行研究,确认其原油具有明显的粘温特性,为剪切变稀型流体。     

管道输送危险废物流变特性测试系统的研制

管道输送危险废物到回转窑焚烧是危险废物最有效的处理方法,蒸馏残渣、蒸馏残液等混合物料的流变特性对管道输送非常重要。根据建立非牛顿流体流变特性方程所需参数,基于Modbus工业现场总线协议利用PLC采集管道压力信号、活塞位置信号、主液压缸压力信号等,并对压差△P和平均流速V进行了修正,确保计算结果准确。实验初步验证了测试系统的可行性,为后续进行流变特性测试做了准备。     

一种新型煤泥分流器的研制

高浓度煤泥在采用管道输送的过程中,由于本身的高聚合性、高内摩擦力等特殊性质很难对其进行均匀分流,以达到均匀给料的目的.本文详细介绍了针对煤泥等粘稠物料进行均匀分流的分流器的工作原理、设计思想、结构特点、工作过程及其应用领域,着重介绍了其通过改变活塞行程进行分流的工作特点.为今后高浓度粘稠物料管道分流设备的应用提供参考依据.     

轴流泵变转速性能试验及内部流场数值计算

研制比转速550 r/min、转速2 900 r/min型QY90-4.4-1.5潜水轴流泵样机。通过型式及变转速外特性试验,得出轴流泵qV-H、qV-Pa和qV-η性能曲线变化规律;验证qV-H、qV-Pa曲线及各转速最优工况之间换算均不满足相似定律,泵综合特性曲线等效曲线与相似抛物线差别较大;采用计算流体力学(Computational fluid dynamics,CFD)方法进行转速对流场影响数值计算,得到不同转速下最优工况叶片表面速度和静压分布,阐明外特性变化规律内在原因;泵转速提高,叶片表面速度增大,内部流动基本符合圆柱层流面无关性假设;同时叶片所受升力增大,叶片背面所承受的负压强进一步降低,易发汽蚀的可能性增大,可以推测汽蚀是制约轴流泵高速化发展的主要因素之一。轴流泵内部液流轴向运动雷诺数较小,难以达到尼古拉兹试验粘性力相似的自动模型化区,且叶栅与单翼型升力系数的差异,也难以保持变转速工况之间升力的相似,这是不满足相似定律的主要原因。     

Non-Newtonian Temperature and Pressure Effects of a Lubricant Slurry in a Rotating Hydrostatic Step Bearing

The purpose of this research was to investigate the pressure and temperature effects of graphite powder lubricant when added to a Newtonian carrier fluid and applied in a rotating hydrostatic step bearing. Temperature and pressure profiles were determined both analytically and experimentally. The rheological behavior of the non-Newtonian lubricant was modeled using a power law model previously shown to approximate experimental data for this fluid. Ethylene glycol was used as the Newtonian lubricant, providing a check on the test apparatus and a base line for comparison with the non-Newtonian graphite slurry.

Data revealed a temperature increase with bearing rotational speed for both fluids and compared favorably with the mathematical predictions. A significantly higher temperature rise was seen in the non-Newtonian lubricant due to the higher shear rates. The pressure profile was not directly dependent on bearing rotational speed in the mathematical model, but experimental data demonstrated a reduction in pressure at higher rotation speeds. This loss was greater for the non-Newtonian lubricant and attributed to temperature dependence of power law constants. It was concluded that the effects of operating speed and temperature on a non-Newtonian lubricant should be considered as well as their greater load-carrying capacity.     

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.     

可调压可视化微间隙Couette流变仪的研究及应用

采用精密的机械加工和独特的气动旋转密封技术,研制出可调压可视化微间隙Couette流变仪。外圆筒旋转内圆筒静止的特点,使该流变仪能产生剪切速率高达105/s数量级稳定的纯剪切流。利用商业旋转流变仪,测量试验用中、低粘度硅油在低剪切速率和不同温度下的粘度,应用粘温关系,推算出高剪切速率下粘性热使粘度下降的量,其值与微间隙Couette流变仪的测量结果较为吻合。在一定的切应力下,观察到淡水和中低粘度硅油在微间隙中发生剪切空化的现象,发现剪切空化的发生还强烈依赖于流体中气体的相对溶解量。     

An experimental evaluation of pre-yield and post-yield rheological models of magnetic field dependent smart materials

The rheological behavior of field-dependent smart fluids in both the pre-yield and post-yield regimes is investigated. Typical viscoelastic and viscoplastic models are employed to model the fluids behavior. Viscoelastic models are used widely in the pre-yield regime. Viscoplastic models are also used extensively in both the pre-yield and post-yield regimes. Two smart fluids including a ferromagnetic nanoparticle fluid and an MR fluid are examined here. Using an MCR300 rheometer, the rheological properties of the fluids in both oscillation and rotational mode are measured. In the oscillation mode, the storage and loss moduli versus frequency are measured. In the rotational mode, shear stress, shear rate, viscosity and torque are measured. In the frequency domain, the pre-yield behavior of the ferromagnetic nano-particle fluid is modeled by Kelvin-Voigt solid model. Also, the three-parameter fluid model is used to model the pre-yield behavior of the MR fluid. Two viscoplastic models including Bingham-plastic and Herschel-Bulkley models are selected to model the rheological behavior of fluids in the time domain. Which model is more appropriate depends on the external magnetic field and the shear rate. Both models are used here to model the fluids’ behavior. The models properly predict the results observed in the experiments.