常用除雾技术现状及发展趋势

介绍了目前常用的除雾技术基本原理及适用范围,重点对丝网除雾器的工作过程、技术原理及影响因素进行了分析和总结;并对目前常用的除雾技术与丝网除雾器的特性与分离性能进行了总结对比,分析认为采用丝网除雾器进行气（汽）液分离时具有较小的压降和较高的分离效率以及结构简单等特点,因此丝网除雾器具有更为广泛的应用前景。     

旋风分离器数值模拟

旋风分离器作为压缩机的级间分离设备,主要用于分离压缩过程中产生的液滴,然而,液体的体积含量对于分离效果有很大影响,通过Fluent软件,对于常规工艺条件和带有大量冷凝液的工艺条件分别进行气、水两相流的模拟,进一步明确旋风分离器的适用范围,为旋风分离器的工程设计及其分离性能的改善提供一定的基础。     

直流降膜式旋风除雾器的流场模拟

为更好地解决三聚氰胺生产过程中尿素洗涤塔的尾气除雾及严重的器壁结疤现象,开发设计了一种新型高效的除雾器--直流降膜式旋风除雾器.液体在除雾器的壁面上形成了一层液膜,防止在器内壁结壳,解决了设备内壁结壳的难题.直流降膜式旋风除雾器结构简单,具有气体流程短、除雾效率高、压降低等特点.利用计算流体动力学(CFD)商业软件FLUENT6.0对直流降膜式旋风除雾器进行了数值模拟研究,结果表明,直流降膜旋风除雾器切向速度呈内部的强制涡和外部的自由涡,流型规整,切向速率、轴向速率有较好的对称性,为除雾器结构优化提供了参考依据.     

轴流式气液旋转分离器及其作为湿气流量计的试验研究

应用旋转固壁替代静止固壁对轴流式旋风分离器的结构进行改进，设计了轴流式气液旋转分离器。试验测试了轴流式气液旋转分离器的机械可靠性和分离效率，测试表明，在一定的工况下，轴流式气液旋转分离器的分离效率最高可达99．99％，且在整个测试过程中没有出现机械故障。测试中发现，轴流式气液旋转分离器还可用作湿气流量计，即从湿气流中分离出气相和液相，通过测量湿气条件下旋转表面的转速和被分离液体的流量并进行插值后，可得到气体的流量。     

一种新型离心式气液分离器分离性能的数值模拟与试验研究

为了研究该分离器的分离性能,通过搭建气液两级分离实验台架进行实验测量,同时应用计算流体力学(CFD)方法对分离器内的气液两相流动进行数值模拟.重点研究了流量、气液比、介质粘度、密度、气泡直径及转鼓转速等六个变量对离心式气液分离器分离效率的影响.通过比较数值计算与实验测定结果,验证了数值模拟方法的可行性.分析结果表明,预测的分离效率变化趋势与实测结果在总体上是一致的, CFD可作为离心式气液分离器设计的有效工具.     

逃液捕集器在发酵罐尾气逃液回收中的应用

结合目前国内外气液分离设备的研发背景,分析了气液分离器的原理、分离形式、分离方法,详细介绍了QYF-B型逃液捕集器的工作原理、特点、安装及其在用户中的实际应用情况,可有效解决传统旋风分离器分离效率低的问题,避免发酵罐尾气逃液现象的发生,保证生产的稳定运行。     

泡状入流条件下离心泵喘振特性试验研究

设计离心泵全流道可视化试验装置，结合高速摄像技术研究泡状入流条件下离心泵的喘振特性，揭示叶轮内气液相分布与泵喘振的关联机制，分析入口体积含气率、液相流量和转速对泵喘振特性的影响，并基于研究对象和试验结果，对比几个典型泵喘振临界体积含气率预测关联式。结果表明，离心泵的喘振主要受泵内气液两相分布影响，当叶轮内流型由气囊流转变为分离流时，泵发生喘振现象；入口体积含气率增加直接导致泵发生喘振，入口体积含气率的变化影响叶轮内流型，进而影响泵的性能；离心泵喘振条件下，通过合理调节液相流量来改变泵内流型，可以减轻泵的喘振；增加转速可以延缓叶轮内气液分离，推迟泵喘振现象发生，增加泵的携气能力，进而改善泵的性能。已有的喘振预测模型获得的临界体积含气率与试验结果相比尚存在一定的偏差，目前仍然缺乏针对蜗壳式离心泵的喘振预测模型。     

中药粉碎中的气固分离

从气固体分离方法与特性入手，对旋风分离器和布袋除尘器的特性和影响因素作了分析。     

梯形折流板除雾器在电镀铬铬雾回收系统中的数值模拟

本研究利用计算流体力学方法对铬雾回收系统中的梯形折流板除雾器内气液两相流进行数值仿真。通过分析得到梯形折流板除雾器叶片间距、流速、弯折角度、长度、高度以及道数等对不同粒径铬雾雾滴的去除效率的影响,得到了不同粒径铬雾雾滴的捕集规律、速度分布规律以及进出口压力差变化规律。分析结果表明,粒径在10μm以下的铬酸雾液滴,惯性力小,去除效率较低,不易被捕集。粒径在10μm以上的铬酸雾液滴,去除效率较高。     

旋风分离器高温高浓度性能试验研究

为预测高温下浓度对旋风分离器分离性能的影响,选用一个直径为300mm的切流反转式旋风分离器在温度673K,入口浓度2-60g/m3范围内进行试验研究。试验用中位粒径为16.47μm的滑石粉作为粉料,试验测得了不同浓度下旋风分离器的分离效率与压降。结果显示,相同入口气液速度下,分离效率与压降均随浓度的升高而降低。     

Further study of minimizing total flowtime for the worker assignment scheduling problem in the identical parallel-machine models

Previously, minimizing total flow time in the model of an identical, parallel machines with nonpreemptive jobs has been investigated. Because the specific problem has been shown as NP-complete, heuristics have been developed for solving it. A shortest processing time for A_i part (SPT-A) heuristic is used for the job scheduling subproblem. In addition, the largest marginal contribution (LMC) procedure is used for the worker assignment subproblem and then minimizes the total flow time. Different values of W (number of workers) are used for further study of the performance of these heuristics developed. In conclusion, for the simplified processing time function, values of W have no significant influence when the heuristics are applied. In other words, no matter what value of W was used when SPT rule was applied, the heuristics generate the same, excellent results.     

定州电厂脱硫系统气-气换热器堵塞原因

为了研究定州电厂湿法脱硫系统气-气换热器（GGH）堵塞的机理,用X射线衍射分析了GGH结垢物的物相组成,测量了脱硫系统除雾器入口与出口的烟速。研究结果表明：垢的主要成分为石膏和CaSO4,飞灰参与了垢的形成过程;除雾器入口气流速度分布不均,入口处最高流速为16．6m／s,局部流速为零,平均流速为8．06m／s,整体流速偏高,导致除雾效率下降;除雾器入口烟气流速偏高,使得脱硫浆液流经除雾器进入GGH,造成堵塞。     

Effect of plate depth on the performance of a Zanker flow straightener

The Zanker flow straightener is one of the flow conditioning devices included in ISO 5167. It consists of a graded perforated plate followed by a section of rectangular honeycomb one pipe diameter in length. Zanker designed the plate to produce fully developed flow conditions and incorporated the honeycomb to remove swirl. The investigation reported here has focused on the performance of the Zanker device with particular reference to the depth of the perforated plate. It has been shown that the depth of the plate has an effect on the performance of the composite device in distorted flows. Also if the plate is sufficiently deep the requirement for the honeycomb section becomes redundant.     

弯曲叶片对跨音速轴流压气机性能影响的数值研究

采用具有不同控制参数的积叠线对Rotor37转子叶片进行周向弯曲造型设计,获得叶片的最佳弯高和弯角。采用数值计算方法研究了叶片弯曲对压气机性能及其内部流动结构的影响,结果表明:弯曲叶片具有良好的变工况性能,新设计的叶片能有效提高压气机的绝热效率和总压比。叶片周向弯曲引起端部低能流体向主流区的迁移,使得端壁和主流区流动状态发生改变,在端壁区流动损失下降,而在主流区流动损失有所增加,同时沿叶高方向上流体的质量流量被重新分配。     

涡轮流量传感器在旋转来流中的特性研究

本文对涡轮流量传感器在旋转来流中的特性进行了理论和实验研究。利用涡轮流量传感器的数学模型,给出了涡轮转速、仪表常数与来流旋转角之间的理论关系式。计算了来流旋转强度及上游直管段长度变化时,仪表常数的变化情况。设计了能获得不同来流旋转强度的旋转发生器,并获得了大量的实验数据。实验结果与理论计算值在较大的流量范围内甚为吻合。     

Effect of channel and plenum aspect ratios on the performance of microchannel heat sink under different flow arrangements

Microchannels based heat sinks are considered as potential thermal management solution for electronic devices. The overall thermal performance of a microchannel heat sink depends on the flow characteristics within microchannels as well as within the inlet and outlet plenum and these flow phenomena are influenced by channel aspect ratio, plenum aspect ratio and flow arrangements at the inlet and outlet plenums. In the present research work an experimental investigation has been carried out to understand how the heat transfer and pressure drop attributes vary with different plenum aspect ratio and channel aspect ratio under different flow arrangements. For this purpose microchannel test pieces with two channel aspect ratios, 4.72 and 7.57 and three plenum aspect ratios, 2.5, 3.0 and 3.75 have been tested under three flow arrangements, namely U-, S- and P-types. Test runs were performed by maintaining three constant heat inputs, 125 W, 225 W and 375 W in the range 224.3 ?? R_e ?? 1121.7. Reduction in channel width (increase in aspect ratio, defined as depth to width of channel) in the present case has shown about 126 to 165% increase in Nusselt number, whereas increase in plenum length (reduction in plenum aspect ratio defined as width to length of plenum) has resulted in 18 to 26% increase in Nusselt number.     

大扩张比涡轮过渡段的数值模拟与改进

为了提高某型涡轴发动机过渡段的气动性能,采用三维数值模拟的方法对其进行了计算分析,讨论了影响过渡段流动的因素,总结了造成过渡段气动性能较差的主要原因是出现了流动分离.对过渡段的外流道进行了改进设计.结果表明通过调整过渡段外流道的曲率变化能够有效地控制过渡段的分离流动,并提高了过渡段的性能,改善了过渡段出口的流动条件.     

LY0型冻干机冻干箱内压力场模拟分析

为了研究药品冻干机冻干室内水蒸气压力分布状态,使用FLUENT软件对LYO型冻干机不同结构的干燥室内水蒸气流场进行了模拟,模拟分析了干燥室中搁板面积、搁板间距、水蒸气升华量对干燥室内水蒸气压力分布的影响。模拟计算结果表明不同结构的干燥室内的水蒸气压力存在明显差异。模拟计算结果可以用于评估冻干机冻干箱内不同部位物料的干燥速率,并为确定冻干机关键结构及工艺参数提供一定的理论参考依据。     

Application of gamma-ray computed tomography for the analysis of gas holdup distributions in centrifugal pumps

In this work, gas–liquid distributions in an industrial centrifugal pump operated at various steady state conditions have been quantitatively determined. Therefore, high-resolution gamma-ray computed tomography (HireCT) has been applied, operated in time-averaging rotation-synchronized CT scanning mode. Detailed studies have been performed on a hydraulic test facility providing authentic operating conditions for industrial centrifugal pumps. The gas phase distribution in the centrifugal pump has been studied for swirling gas–liquid two-phase flow as an inlet flow regime and at defined inlet gas volumetric flow rates between 0% and 5%. In this way, the influence of the inlet flow boundary conditions on the performance of the centrifugal pump as well as the gas holdup distribution within the impeller region could be successfully determined.