用于细颗粒分离的水力旋流器的压力特性研究

对用于细颗粒分离的水力旋流器的压力特性 (压力降及压降比 )与流量、分流比、旋数、溢流口和底流口直径及气液比等主要参数之间的关系进行了深入的研究与分析。研究发现 ,水力旋流器内部压力降分别随流量、分流比、旋数及气液比的提高而加大 ,压降比则分别随流量、分流比、旋数的提高而降低。随着溢流口直径的加大 ,水力旋流器的溢流压力降减小 ,而压降比也随之降低 ;随着底流口直径的加大 ,底流压力降减小 ,压降比随之升高。分析可知 ,减少旋流器能耗的有效方法是降低旋数 ,或者减少混合介质中的气液比     

除油旋流器压降比的数学模型

实验研究了直径为 35mm的除油水力旋流器能量耗散与分流比的关系 .结果发现 ,当改变溢流孔径 (分别为 4、 6、 8mm)和入口流量 (分别为 30、 40、 5 0、 6 0、 70L·min^-1)时 ,只要分流比小于 2 5 % ,旋流器的能量耗散在不同入口流量下都能保持与入口流量对应的某一常数值 .当入口流量分别为 30、 40、 5 0、 6 0、 70L·min^-1时 ,旋流器的能量耗散大约分别为 10、 30、 80、 140、 2 0 5N·m·s^-1.根据旋流器的这一特征 ,并结合理论分析 ,建立了除油水力旋流器压降比数学模型 .该模型预测计算的压降比与分流比关系曲线与实验室测定的结果能很好地吻合     

高海拔地区水力旋流器旋液分离过程CFD模拟与结构优化

针对氯化钾冷结晶器溢流液分离问题，提出使用水力旋流器进行固液分离。采用CFD数值模拟方法对水力旋流器的分离过程进行计算，研究在高海拔地区下水力旋流器筒径、溢流口直径、入口流速、锥角等因素对其流动特性和分离性能的影响。结果表明：筒径Dc=200 mm时分离效果最好；溢流口直径d0的增大会使分离效率与压降减小；增大入口流速会使分离效率先上升再下降，且压降随入口流速增大而增大；锥角α减小，水力旋流器分离效率增加并且压降减小，海拔高度的改变基本不改变水力旋流器的分离效率与压降。经分析可知：当Dc=200 mm、d0=56 mm、α=10°、入口流速为9 m/s时，粒径在20μm以上的颗粒分离效率可以达到80%以上，此时压降为0.26 MPa，整体性能最好。     

液液水力旋流器流场特性与分离特性研究(五)──压降比的影响因素分析

对液液水力旋流器的压降比影响因素进行了简单的分析，分别研究了液液水力旋流器大、小锥角变化对其压降比的影响，并对其影响程度进行了细致的分析。     

α型水力旋流器的性能研究

研究以水-铬渣为实验物系,测定了α型水力旋流器和常规型水力旋流器的分级效率和压降。实验结果表明,α型水力旋流器的分级效率明显地高于常规型旋流器,分割清晰度高,其压降约为常规型水力旋流器压降的70%,具有明显的节能效果。     

水力旋流器结构与分离性能研究（二）：溢流管结构

研究了水力旋流器溢流管结构形状对其分离性能的影响，结果表明：溢流管采用３０°渐扩管加锥结构时，水力旋流器处理能力最高；溢流管加虹吸装置时，水力旋流器分离修正总效率最高、分流比最小；采用普通型薄壁直圆管结构时，水力旋流器修正分离粒度ｄ５０Ｃ最小、分离精度α值最高。     

超稠油采出污水常温旋流分离试验研究

超稠油采出污水由于具有密度大、悬浮物高、乳化严重等特点,目前常用的三段处理工艺即除油-混凝沉降(或气浮)-过滤已不能满足工艺要求.水力旋流器具有结构简单、分离时间短、没有运动部件等优点,在处理油田采出水领域得到越来越多的应用.通过对一定结构的水力旋流器进行研究,改变操作参数,得到了实验用的水力旋流器最佳入口流量和最佳溢流比,为以后工业应用打下基础.     

水力旋流器溢流管结构对微细颗粒分离的影响

针对直径为50 mm的小直径水力旋流器,考察了溢流管插入深度和壁厚以及进口流量对微细物料分离效率的影响,并利用正交分析法得到了溢流管最优的插入深度、壁厚及最适的进口流量。此外,考察了两种套筒式溢流管对水力旋流器分离性能的影响。最后,在最优溢流管结构的基础上,探讨了分流比对分离效率的影响。结果表明：水力旋流器的直筒段具有一定的分离作用;对于微细物料的分离,溢流管采用薄壁且插入深度与水力旋流器直筒段长度相当的设计,有利于提高微细颗粒的分离效率。针对水力旋流器溢流管插入深度与其直径的最佳比例,小直径水力旋流器的比大直径水力旋流器的大,表明它们的分离行为存在着较大的差异。     

水力旋流器新型出口挡板结构对分离性能的影响

针对小直径水力旋流器,设计了不同内置挡板式的溢流管和底流管,实验研究了新型出口挡板结构对水力旋流器分离性能的影响。研究结果表明:内置挡板溢流管适用于处理量较大的工况,与传统溢流管相比,分离效率略有降低,但在高流量下其压降的降低幅度可达11.11%,挡板宜采用相对较窄、较短、三块120°间隔设计方式;底流管内置挡板采用十字交叉结构可稳定内旋流,使分离效率最大可提高5.96%;新型内置挡板的溢流口与底流口相耦合,可同时实现提高分离效率和降低压降的目标。此外,在相同情况下,发现溢流管内置挡板可消除水力旋流器内部的"空气柱",据此推断"空气柱"并非由内部空气形成,而是其内部负压中心形成的某种湍流程度较高的强制旋流涡。     

水力旋流器溢流管结构对微细颗粒分离的影响

针对直径为50 mm的小直径水力旋流器,考察了溢流管插入深度和壁厚以及进口流量对微细物料分离效率的影响,并利用正交分析法得到了溢流管最优的插入深度、壁厚及最适的进口流量。此外,考察了两种套筒式溢流管对水力旋流器分离性能的影响。最后,在最优溢流管结构的基础上,探讨了分流比对分离效率的影响。结果表明:水力旋流器的直筒段具有一定的分离作用;对于微细物料的分离,溢流管采用薄壁且插入深度与水力旋流器直筒段长度相当的设计,有利于提高微细颗粒的分离效率。针对水力旋流器溢流管插入深度与其直径的最佳比例,小直径水力旋流器的比大直径水力旋流器的大,表明它们的分离行为存在着较大的差异。     

Flow Pattern and Pressure Drop for Small Long‐Cylinder Cyclones Operating at High Flow Rates

To address the gas flow pattern and pressure drop characteristics for small long‐cylinder cyclones (SLCCs) in the high operating flow rate range, experimental investigation and computational fluid dynamics (CFD)‐based simulation were performed. The pressure drop coefficient depends insignificantly on the Reynolds number at high flow rates. The tangential and axial velocities present the Rankine vortex and the roughly inverted V‐shaped distribution, respectively, similar to those in typical cyclones. The CFD simulation approximated well the experimental data of pressure drop. The pressure drop caused by vortex loss, turbulent energy loss, and resistance loss accounted for 72.5 % of the total pressure drop. The Stairmand model was found to be relatively accurate among the classical pressure drop models for the proposed cyclone. The results may help in the design and applications of cyclone separators and reactors.     

Experimental Study of Particle Collection by Small Cyclones

A new set of experimental data on the particle collection characteristics of small cyclones is reported. The collection efficiency for particles ranging from 2 to 10 μm in diameter was measured systematically for nine cyclones at flow rates ranging from 8.8 to 18.4 L/min. Special emphasis was given to the effects of the exit tube size and of the cyclone body size on the particle collection efficiency. The size ratio of the exit tube to the cyclone body was varied from 0.24 to 0.80. The experimental results show that the stiffness of the particle collection cutoff with size does not change noticeably with a change in the cyclone body size while operation of a cyclone at a low flow rate can cause the particle collection characteristics to become less stiff. It was also found that the exit tube diameter influences the particle collection efficiency substantially, with results showing that as the exit tube size is decreased, the collection efficiency increases. A large cyclone body size increases the efficiency. However, when the cyclone body is increased excessively, the collection efficiency appears to decrease somewhat. The experimental data were compared with existing cyclone theories and Barth's (1956) theory was found to be in good agreement. Finally, the exit tube was found to affect substantially the pressure drop of cyclones. As the exit tube size increased, the pressure drop decreased. However, when the exit tube size was further increased until it approached the body size, the pressure drop increased again.     

流化床中旋风下料管的物理模型

In most industrial fluidization units, two- or three-stage cyclone systems are used to clean the product gases. To return the solids to the bed, these cyclones are fitted with diplegs. By pass of gas from the bed through the dipleg is partially overcome by the back pressure build-up in the dipleg and by adding a trickle valve at the bottom of the dipleg. Diplegs of primary cyclones, operating at a high solid loading behave differently from diplegs of secondary and tertiary cyclones which operate at low solid loading. Both types have been investigated by pressure drop measurements, visual observation and by measurements of the air flow rate flowing up the riser. The primary dipleg was also studied using electrical capacitance tomography. The results are reported hereafter and will give a first indication towards the right design of the dipleg and the selection of the trickle valve. The influence of gas flow in the dipleg on the conversion in a catalytic fluidized bed reactor is found to be negligible.     

Developing an untwisting device for cyclones and estimating its parameters

A new design is proposed for an untwisting device in order to reduce the pressure losses in cyclones. The results of experimental studies on the effect of an untwisting device on the pressure drop and the efficiency of cleaning in cyclones are given. The geometric and structural untwisting device’s parameters that are most rational from the viewpoint of reducing the pressure drop at the same separation efficiency are determined. On average, the application of the given untwisting device allows us to reduce the energy consumption of the most widespread TsN-11 and TsN-15 cyclones by 29 and 27%, respectively, at the same degree of cleaning.     

旋风筒阻降浅论

介绍了旋风筒阻降(压降)的定义及其测量方法、旋风筒阻降的计算公式,分析了操作参数和结构尺寸对旋风筒阻降的影响、旋风筒阻降的种类及各种减阻措施。     

差异旋风分离器并联性能测量及流场分析

通过改变旋向和芯管直径,设计了3种差异旋风分离器,并按中心对称方式组成了3种并联方案：相同分离器、旋向差异分离器和芯管差异分离器并联。在冷态实验装置上,测量了单分离器和并联分离器的性能,并利用FLUENT软件分析了并联分离器的流场。结果表明,并联分离器的效率均高于单分离器,且效率-气速曲线未出现“驼峰”;与相同分离器并联相比,旋向交替变化时并联总压降较小,分离效率也更低,但各分离器流量分配均匀,未发现“窜流”现象;当芯管有差异时,并联总压降增大,各分离器进口流量分配不均匀,且进、出口流量平均相差6.0%,公共灰斗中存在“窜流”,旋流稳定性变差,效率降低。为了保证并联分离器的性能,应采用相同分离器对称并联的方式。     

柱形旋流器油水分离效果研究

建立了一套柱形旋流器油水分离实验流程。通过改变油水两相泵入速度、溢流口流量等操作参数,得到了入口流速、分水率对分离效果的影响趋势,并比较了二级柱形旋流器并联和串联两种连接方式的分离效果。结果表明,一定结构的柱形旋流器存在最优的入口流速和分水率;在2.8 m/s的入口流速下,二级柱形旋流器并联油水分离效果最好。     

A Mathematical Model to Compare the Efficiency of Cyclones

Tangential cyclones modified to form spiral cyclones are very efficient in separating solid particles from dust laden gases. They offer a lower gas pressure drop and higher particle separation efficiency when compared to basic tangential cyclones. Their high performance is believed to be related to their special structure. A mathematical model is introduced to explain why a spiral cyclone is more efficient than a tangential one. An experimental apparatus is designed to compare both the performances of spiral and tangential cyclones and to check the effectiveness of the model equations. The experimental data were found to be consistent with the model predictions.     

Modelling of the Pressure Drop in Tangential Inlet Cyclone Separators

This article introduces a new mathematical model that predicts the pressure drop in a tangential inlet cyclone. The model calculates the pressure drop from the frictional losses in the cyclone body, using a wall friction coefficient based on the surface roughness and Reynolds number. The entrance and exit losses are also included in the model by defining new geometrical parameters. The pressure drop coefficient is obtained as a function of cyclone dimensions and operating conditions. The model is validated by studying 12 different cyclones presented in the literature. Comparison of the model results with predictions and measurements published in the literature show that the new model predicts the experimental results quite well for a wide range of operating conditions covering a flow rate of 0.3–220 l/s and a temperature range of 293–1200°K, in different cyclones. The pressure drop coefficient is also examined in view of the outlet pipe diameter, friction coefficient, surface roughness, and Reynolds number.