For calculation of the parameter G, it is required that the fixed bed height does not exceed the conical appa- ratus zone。 Reinlet,bsf is the Reynolds number in the gas inlet area at the beginning of stable spouting。
The Archimedes number was calculated as following:
gas gas
More information about the Re-G-Ar diagram can be found in Gryczka et al。 (2008)。 Fig。 2 shows the ex- perimentally obtained overpressure and bed pressure drop values as a function of the gas throughput。 At dif- ferent inlet gas volume flows (points 1 to 14), gas phase pressure fluctuations over the entire bed were meas- ured with a frequency of 1 kHz for a period of 10 seconds and subsequently the fast Fourier transformation algorithm was applied to each of these measured spectra (see the two examples shown at the right hand side of Fig。 2)。
Fig。 2: Measured pressure drop of the empty and filled apparatus and resulting bed pressure drop (mate- rial: -Al2O3 spheres; d50,3 = 1。75 mm; = 0。048 mm; s = 1040 kg/m3)。
By visual observations and by analysis of the progression of the bed pressure drop as well as of the FFT, conclusions on the dynamic bed behavior can be made and the stable spouting operation range could be de- termined (exemplary see Fig。 2 for the “stable spouting domain”)。 Having performed that procedure with several particle systems, bed masses, free inlet gas areas and inlet gas velocities, the stable operation range could be established in the Re-G-Ar-diagram。 The stable operation range of the investigated novel spouted bed apparatus with slit-shaped gas inlet has been added to an existing Re-G-Ar-diagram that already implied operation ranges of different other plant constructions (Fig。 3)。 The curves a, c, e, g and i indicate the begin- ning of stable operation and the curves b, d, f, h and j the end of stable operation of the corresponding appa- ratus。 The pneumatic operation ranges of the fluidized bed and the several spouted bed designs make com- parisons of different apparatus constructions possible and thus facilitate the choice of the optimal apparatus for a certain material。 Fig。 3 shows that the stable operation range of the investigated spouted bed apparatus is located at very low G-values affected by very low gas inlet areas。 Due to the resulting high inlet gas ve- locities, excellent heat- and mass transfers are enabled which offer advantages in conducting drying, granu- lation or coating processes。摘要
最近，干燥过程以及造粒，结块或涂层工艺的背景下的喷动床技术的重要性有显著增加。关于非常细小的或非球形粒子的细微系统难以流化，通常不能在常规流化床中处理。与那些流化床相比喷动床技术以其特有的流动结构在控制条件下提供了稳定的流体化机会。我们对一个新的有两个可调进气口的流体动力学喷动床进行了研究。通过分析气体脉动光谱和快速傅立叶变换算法，不同的操作制度被识别和描绘成图形。此外，颗粒固相运动的连续CFD模拟依靠欧拉/欧拉方法的装置和与实验得到的速度矢量的比较，将会通过粒子图像测速（PIV）测量领域呈现。文献综述
简介
在食品、医药、化工、精细和分散的固体被分别处理和制作。类似于传统的流化床，喷动床以其良好的固相混合和它们密集的传热和传质特性之间的流体相（气）和固相产生近等温条件为人所知。喷动床流程结构的特点是设备结构简单。像流化床技术一样，喷动床技术可以应用于细微系统混合、传热和传质过程，如冷却，干燥（Kmiec等人。（1994））、例如喷雾造粒的煅烧、燃烧、气化以及复杂的多相过程（Hatano等人。（2004）），凝聚（Jacob等人。（2005））、颗粒分层和涂料（kfuri和塔斯（2005））和化学反应。喷动床与传统流化床相比有以下基本差异： 喷动床装置的气动特性英文文献和中文翻译(3):http://www.youerw.com/fanyi/lunwen_92156.html