简述降低旋风除尘器内阻力方法.doc

简述降低旋风除尘器内阻力方法旋风除尘器利用离心力和电场力的共同作用分离粒子。旋风除尘器内安装电晕极（称旋风除尘器）但不加电压的运行工况称为旋风除尘器的“静态”工况，此时的除尘效率称为旋风除尘器的静态除尘效率。为了研究安装电晕极对旋风除尘器除尘效率的影响，对常规旋风除尘器和旋风除尘器两种情况分别进行了各种入口风速下的除尘效率实验。常规旋风除尘器选用长筒体型，筒体直径为40mm、入口尺寸为270110mm，排灰口直径为116 mm。排气管直径为200 mm，排气管插入深度460 mm。在常规旋风除尘器内安装电晕极构成旋风除尘器，电晕极由15根直径4 mm钢筋构成网状结构并固定在排气管上。实验粉尘为400h目滑石粉，发尘浓度控制在5g/m3左右。Cyclone by using the common role of centrifugal force and electric field force to separate particles. Corona pole installed in the cyclone (cyclone) but do not add voltage operation called static condition of cyclone, called a cyclone dust removal efficiency at a moment when the static dust removal efficiency. Installation of corona in order to study on the cyclone dust removal efficiency, the influence of the conventional cyclone separator and cyclone two situations respectively under various inlet dust removal efficiency experiment was carried out. Conventional cyclone choose their body, cylinder diameter of 40 mm, entrance size is 270 * 110 mm, ash discharge mouth diameter of 116 mm. Exhaust pipe diameter of 200 mm, the exhaust pipe inserted into the depth of 460 mm. In a conventional cyclone installation of corona polar cyclone, corona pole consists of 15 root diameter 4 mm steel mesh structure and fixed on the exhaust pipe. Experiment is 400 h mesh talc powder dust, the dust concentration control in 5 g/m 3 or so. 常规旋风除尘器安装电晕极后除尘效率明显提高，除尘效率的变化 规律 与常规旋风除尘器除尘效率的变化规律相同，即先随着入口风速的增加而增加，至一最佳运行工况后，除尘效率又有所降低。常规旋风除尘器最佳运行工况在入口风速v=17m/s左右，此时，其总除尘效率达到了80%；而安装电晕极以后，旋风除尘器的静态最佳运行工况约在入口风速v=20 m/s左右，静态总除尘效率达到约85%，增幅为6.3%左右。这说明仅仅安装电晕极而不加电压，就能使旋风除尘器的除尘效率明显提高电晕极。在旋风除尘器内具有提高效率的作用。Conventional cyclone dust cleaning efficiency obviously improved after installation of corona pole, the changing rule of the dust removal efficiency and the changing rule of the conventional cyclone dust removal efficiency is the same, namely first increased with the increase of inlet wind speed increase, to the best operation condition, the dust removal efficiency is reduced. Conventional cyclone best operation condition at the entrance to the wind speed v = 17 m/s or so, at this point, the total dust removal efficiency reached 80%; And after the installation of corona pole, the static optimal operating conditions of cyclone about entry about 20 m/s wind speed v =, static total dust removal efficiency of about 85%, growth of around 6.3%. This shows only installing corona pole and not add voltage, can make corona polar cyclone dust removal efficiency increased greatly. Within the cyclone has the function of improving efficiency. 二、旋风除尘器的阻力Second, the resistance of the cyclone 由上述可知，电晕极在旋风除尘器内具有提高效率的作用，通过实验发现，电晕极在旋风除尘器内也具有降低阻力的作用。By above knowable, corona has improve the efficiency of the function within the cyclone dust collector, found through experiments, corona pole inside the cyclone dust collector also has the effect to reduce resistance. 旋风除尘器阻力系数2=4.81，常规旋风除尘器的阻力系数1=9.21，即旋风除尘器的阻力系数比常规旋风除尘器的阻力系数降低了约47%。因此，靠电晕极的作用，较好的改善了旋风除尘器的阻力特性，与常规旋风除尘器相比，旋风除尘器是一种低阻力的粒子分离设备，这对于节能具有极为重要的实际意义。Cyclone separator resistance coefficient factor 2 = 4.81, the conventional cyclone drag coefficient is deduced. 1 = 9.21, namely the cyclone of drag coefficient than the conventional cyclone resistance coefficient was reduced by about 47%. By corona pole role, therefore, better to improve the resistance characteristic of the cyclone, compared with the conventional cyclone, cyclone dust collector is a kind of low resistance particle separation equipment, it has very important practical significance for energy conservation. 综上所述，在常规旋风除尘器内安装电晕极，具有降低阻力和提高静态除尘效率（称为“降阻增效”）的作用，为什么电晕极会对旋风除尘器的阻力和效率有这么大的影响呢？下面将进行分析。To sum up, in a conventional cyclone installation of corona pole, with lower resistance and static dust removal efficiency (called drag reduction efficiency), why is corona pole on the resistance of the cyclone and the efficiency have so much influence? Here will be analyzed. 三、电晕极降阻增效的原因分析Three, corona resistance reduction efficiency analysis of the reasons 切向速度的大小和径向速度分布直接影响颗粒分离的效率，同时轴向速度分离影响了粒子在旋风除尘器内有效分离区域的停留时间，必然对颗粒的除尘效率产生较大的影响。Tangential velocity and radial velocity distribution directly affects the size of the particle separation efficiency, separation of axial velocity at the same time affected the particle residence time in the valid for cyclone separation area, is a larger impact on particle of dust removal efficiency. 旋风除尘器流动阻力主要由三部分组成：即进口局部阻力、旋风筒内旋涡流场中的阻力、排气芯管内的流动阻力。Cyclone flow resistance is mainly composed of three parts: namely the import local resistance, the vortex flow field in the cyclone cylinder, exhaust resistance in the core tube flow resistance. 可见，旋风除尘器的阻力和除尘效率与其内部的流场分布密切相关，要分析电晕极降阻增效的原因，就需要知道旋风除尘器内的流场分布。Visible, the resistance of the cyclone separator and the dust removal efficiency is closely related with its internal flow field distribution, to analyze the cause of corona resistance reduction efficiency extremely, just need to know the distribution of flow field in the cyclone. 为了研究电晕极安装前后旋风除尘器内三维速度分布的变化规律，分别对旋风除尘器内不安装电晕极（称常规旋风除尘器）和旋风除尘器内安装电晕极（称旋风除尘器）两种情况钢塑土工格栅在相同的入口流速下进行了流场测试，流场测试仪器为五孔探针，在除尘器锥体部分及其他一些位置，电晕极比较密集，有的地方五孔探针无法插入，测点适当减少。某些断面在半径的二分之一到三分之一处均无法读取数据（4、5孔的压力不能调到平衡），分析认为由于电晕极对于筒体内流场的扰动，这些位置气流较为紊乱，使4、5孔无法保持压力平衡。Before installing corona in order to study the changing rule of the three dimensional velocity distribution in cyclone dust collector, were not installed inside the cyclone separator corona (called a conventional cyclone) and cyclone corona pole (cyclone) installed in the two cases under the same inlet velocity of the flow field test, the flow field test equipment for the five hole probe, the cone part in filter and some other location, corona pole is more intensive, in some places the five hole probe cant insert, measuring point appropriate reduced. Some cross section in 1/2 to 1/3 radius are unable to read data (4, 5 hole pressure cannot be transferred to the balance), and analysis that the corona in cylinder flow field disturbances, the airflow was disorder, make 4 or 5 hole cannot keep balance of pressures. 1切向速度的作用1. The role of the tangential velocity 安装电晕极后，切向速度的分布变得平缓、峰值降低。内涡旋不再是强制涡流动， 文献 也得出了类似的结论。另外，内外涡旋交界面半径明显外移，即内外涡旋交界面直径由常规旋风除尘器的0.5 de外移为1.2de(de为排气管直径)。矿用风机在筒体和锥体的上半部，下行流区的切向速度有所增大，上行流区的切向速度明显减小，在除尘器内的整个流动区域，平均切向速度明显降低。After installation of corona pole, the distribution of tangential velocity becomes calm, peak decreases. Within the vortex is no longer forced vortex flow, the literature has also reached a similar conclusion. In addition, the inner and outer vortex offshoring interface radius is obvious, namely the vortex boundary between inside and outside diameter of the conventional cyclone offshoring DE DE 1.2 0.5 for exhaust pipe diameter (DE). In the upper half of the cylinder and the cone, downward flow of tangential velocity is increased, the upward flow of tangential velocity decreases obviously, the flow of the dust collector, the area, an average of tangential velocity is decreased obviously. 2轴向速度的作用2. The role of the axial velocity 旋风除尘器上、下行流交界面内移，即上行流区变宽。在下行流区，轴向速度的绝对值减小，这说明粉尘粒子在旋风除尘器的有效分离区域内的停留时间增加，这对离心力分离粒子是有利的，能够提高除尘效率。另外，轴向速度梯度减小，内摩擦阻力降低，有利于旋风除尘器的减阻。Cyclone, downward flow within the interface on the move, which widened upward flow area. In the downstream area, the absolute value of axial velocity decreases, and it shows that effective dust particles in the cyclone separation area of residence time increases, the centrifugal separation particle is favorable, can improve the efficiency of dust removal. In addition, the axial velocity gradient decreases, and internal friction resistance is reduced, is advantageous to the cyclone drag reduction. 3径向速度及压力分析的作用3. Analysis of the radial velocity and pressure 径向速度分布比较紊乱，尤其在电晕极附近，径向速度分布与常规旋风除尘器相比有较大波动。径向速度方向基本都是向心的，其值的大小与常规旋风除尘器相比没有明显的 规律 ，大多数稍微小于原旋风除尘器的相应值，由于切向速度和径向速度对粒子的分离起着相反的作用，前者产生离心力使粒子做向外筒壁的径向运动，后者则使粒子做向心的径向运动从而进入内漩涡。径向速度值的减小可提高除尘效率。Radial velocity distribution is disorder, especially near corona pole and radial velocity distribution compared with the conventional cyclone have greater volatility. Basic it is centripetal radial velocity direction, the size of its value compared with the conventional cyclone had no obvious regularity, most slightly less than the corresponding value of the cyclone, due to the radial and tangential speed plays an opposite role in the separation of particles, the former produces centrifugal force to make particles do outward wall radial motion, which make the particles be centripetal radial movement to enter within the vortex. The decrease of the radial velocity values can impr