压缩空气搅拌与机械搅拌混凝的比较

针对压缩空气搅拌混凝工艺在污水处理上的广泛应用,用模型试验来确定压缩空气搅拌反应的最优条件;通过该模型试验与机械搅拌下的烧杯试验进行比较,对试验结果进行分析得出两类搅拌方式的优缺点。试验结果表明,空气搅拌试验三阶段的最优反应条件为混合时间、一级反应时间和二级反应时间分别为1,3和5min,曝气量为0.4,0.04和0.02m3/h。在空气搅拌试验的混合阶段,大的曝气量并没有改善出水的剩余浊度。空气搅拌试验在混凝时间、药剂用量上具有优势,但在沉淀性能上机械搅拌要优于空气搅拌。与烧杯试验相比,该模型试验对压缩空气搅拌混凝工艺的工程设计与生产运行更有针对性。     

搅拌对Ni—P—MoS2化学复合镀的影响

论述了各种搅拌方法，如空气氧、氮和电磁搅拌对Ｎｉ－Ｐ－ＭｏＳ２化学复合镀层性能、外表的影响，通过试验对比得出，镀液的搅拌非常重要，是必不可少的，而对Ｎｉ－Ｐ－ＭｏＳ２复合镀镀槽来说，空气搅拌比其它搅拌方式要好。文中对几种搅拌方法所取得的试验进行了分析比较。     

高性能混凝土振动搅拌试验研究

为了研究振动搅拌对高性能混凝土的影响,采用普通搅拌与振动搅拌在不同搅拌时间下对比试验的方法,开展了对高性能混凝土坍落度、扩展度、倒坍落度筒排空时间、抗压强度的试验研究.结果表明:相比普通搅拌,采用振动搅拌时,新拌混凝土倒坍落度筒排空时间明显减少;相同搅拌时间下,在龄期3d、7d和28d时混凝土抗压强度分别提升了3.5％、5.7％和8.7％;搅拌时间减少40 s时,在龄期3 d、7 d和28 d时混凝土抗压强度分别提升了5.0％、17.2％和13.8％.说明与普通搅拌相比,振动搅拌可以降低混凝土的塑性黏度,改善混凝土的工作性,提高混凝土的抗压强度和搅拌效率,对于工程应用有重大意义.     

φ6.5×15米空气搅拌库“邻吹法”吹气及其自动控制系统

我厂有四座φ6.5 ×15米空气搅拌库,专为入窑前生料均化之用。长期以来,由于搅拌方式不对,搅拌效果一直不理想。最近,合肥水泥研究设计院对我厂的空气搅拌库采取不同搅拌方式作了几组试验,结果见表1。显见,“邻吹法”在120分钟搅拌时间的均化系数H值最佳。又反复用此法进行了几组试验,得到的H_(m4x)=7.6。因此,现在我厂已正式确定用“邻吹法”对生料进行搅拌。     

制备工艺对微乳化柴油稳定性能的影响

为了考察制备工艺对微乳化柴油稳定性能的影响,采用单因素变化试验和正交试验设计安排试验,系统分析了制备微乳化柴油时的温度、搅拌速度、搅拌方式、试剂的添加顺序以及各工序搅拌时间对其稳定性能的影响。结果表明:温度为25～35℃,搅拌速度为300～500r/m in,添加顺序为乳化剂和柴油先混合,再加入水,最后加入助乳剂,各工序搅拌时间均为5m in时所制备的微乳化柴油稳定性好。结论为制备微乳化柴油时温度、搅拌速度、搅拌时间以及添加顺序对其稳定性能影响较大,搅拌方式对其稳定性能影响较小。     

全氟聚醚聚合釜搅拌转速的设计

研究了全氟聚醚聚合釜的搅拌转速设计问题。根据传热方面的要求选用了卧式釜。依据理论推导并结合试验,获得了全氟聚醚中试釜的搅拌功率与搅拌转速的关系式。     

氧化铝种分槽后加搅拌装置的改造

通过对原搅拌装置搅拌轴支撑结构改造设计,消除了振动,使其运转平稳高效,同时满足了工业试验的需要。     

国产33米~3氯乙烯聚合釜搅拌装置的研究

在模试釜中,对国产33米~3氯乙烯聚合釜搅拌装置进行了模拟试验,研究了搅拌装置的结构,流动状况和动力、循环、混合等搅拌特性,找出了存在的问题。在釜体结构不变的条件下,提出了搅拌桨叶的改进方案。     

振动搅拌对混凝土性能的影响

试验研究了振动搅拌对混凝土强度、含气量和工作性能的影响,结果表明:振动搅拌可以显著提高混凝土强度,但是随着养护时间增长,普通搅拌与振动搅拌混凝土试样强度差异减小;振动搅拌可以显著提高混凝土的含气量;振动搅拌对混凝土粘聚性和保水性影响不大,但是会降低混凝土的流动性。     

高速混合制粒机的实验研究

对固体颗粒在高速混合制粒机内的搅拌混合进行了试验。试验为固定一个物料体系 ,进行三因素 (主搅拌桨转速、制粒桨转速、混合时间 )三水平的正交试验。研究了主、辅搅拌桨转速及混合物料物性对混合效果的影响。从实践上分析了混合效果与各结构参数及操作参数的关系。通过找出最佳混合参数组合 ,给出最适混合转速及最适混合时间     

HE HYDROLOGY OF OVERLAND FLOW IN WETLANDS

An experimental study on mixing, degree of suspension and power consumption in solid-liquid suspensions was done. A system similar to those found in anaerobic fermentation processes of animal manures was used, and an existing mixing equipment was adapted for the study. Power consumption and degree of suspension for both mechanical mixing and mixing by gas was determined. The influence of variables such as geometry, solids concentration, stirrer velocity, and gas velocity was studied, discussed, and compared to data from the literature. Best results were obtained for gas mixing, the power consumption being about one fourth of that required by mechanical agitation. Finally, extended correlations relating Power and Reynolds numbers for mechanical mixing and mixing by gas are proposed.     

销钉机筒挤出机螺杆圆周展开面内物料流动与混合的数值分析与实验

在一定简化条件下,对销钉机筒挤出机螺杆圆周展开面内的流场及分布混合效果以及销钉个数对流场和分布混合效果的影响进行了数值与实验研究.提出了流场中某点混合效果、整个流场平均混合效果以及混合效果统计分布的数值计算与评价方法.数值分析结果与实验结果具有较好的一致性.结果表明,销钉及螺棱切槽对物料具有明显的强化流动与混合的作用;6个销钉结构模型混合效果好于3个销钉结构模型,3个销钉结构模型好于有切槽无销钉结构模型,有切槽无销钉结构模型好于无切槽无销钉结构模型;有销钉结构较无销钉结构的平均混合效果提高30%～40%;有销钉结构随着时间的延长,混合效果不断提高,无销钉结构随着时间的延长,当混合效果达到一定值后则不再提高.     

双转子连续混炼机混炼段分散混合效率的研究

利用有限元分析软件Polyflow对自行设计的ECM30型双转子连续混炼机转子的混炼过程作了三维等温流场分析,借助于剪应力和混合指数对转子的分散混合效率进行了分析研究;讨论了不同的操作工艺对分散混合效率的影响。该数值模拟的结果将有助于针对不同的聚合物采用不同的混炼工艺,使得聚合物在转子中的混合达到最优化。     

DISPERSION OF GAS AND LIQUID IN BUBBLE COLUMNS OF HOMOGENEOUS BUBBLE FLOW REGIME

Mean gas holdup, lateral distribution of gas holdup and axial mixing of gas and liquid were measured in bubble columns of 12 and 19cm i.d. The lateral distribution of gas holdup was strongly dependent on the flow regimes in the column. The axial mixing of liquid in the homogeneous bubble flow regime was much smaller than that in the heterogeneous bubble flow regime, and was not expressed by existing correlations. The axial mixing of liquid in the homogeneous bubble flow and the intermediate flow regime was simulated with a flow model based on the lateral distribution of buoyancy force and the effective viscosity. The axial mixing of gas was larger than that of liquid.     

EXPERIMENTAL STUDY ON MIXING: POWER CONSUMPTION AND DEGREE OF SUSPENSION

An experimental study on mixing, degree of suspension and power consumption in solid-liquid suspensions was done. A system similar to those found in anaerobic fermentation processes of animal manures was used, and an existing mixing equipment was adapted for the study. Power consumption and degree of suspension for both mechanical mixing and mixing by gas was determined. The influence of variables such as geometry, solids concentration, stirrer velocity, and gas velocity was studied, discussed, and compared to data from the literature. Best results were obtained for gas mixing, the power consumption being about one fourth of that required by mechanical agitation. Finally, extended correlations relating Power and Reynolds numbers for mechanical mixing and mixing by gas are proposed.     

几种旋转式反应注射混合元件混合性能的实验研究

在深入分析旋转式Kenics混合元件混合机理基础上开发出两种新型混合元件,将这两种混合元件与Kenics混合元件的混合性能进行实验对比。结果表明,开发的螺纹元件能够取得与Kenics混合元件相近的混合效果,所得制件表面质量最好;而交错平板元件混合效果差,反应不均匀,反应速度慢;旋转式Kenics混合元件的螺旋结构产生的拉伸和剪切在混合过程中起主要作用,交错平板结构的分割作用是次要的。     

铜纤维长度对ABS/铜纤维复合材料导电性能的影响

研究了在(丙烯腈/丁二烯/苯乙烯)共聚物(ABS)/铜纤维复合材料混炼加工过程中基体粘度、剪切速率和铜纤维的原始长度对混炼后铜纤维长度的影响,并讨论了混炼后的铜纤维长度对复合材料导电性能的影响.结果表明,高剪切速率对铜纤维长度的破坏作用远远大于低基体粘度对铜纤维长度的保护作用.较长铜纤维在混炼过程中缠绕在一起不易分散均匀.研究发现,选用合适的加工工艺,原始长度较短的铜纤维在混炼后仍然可以保持一定的长度,并且由此制得的复合材料导电性能优于由原始长度较长的铜纤维制得的复合材料.     

下压式多段混合搅拌槽的实验研究

用饱和NaCl溶液作示踪剂,计算机动态数据采集,研究了0.65L下压式多段混合搅拌槽(DPSTMM)流通截面放大25倍、体积放大100倍后轴向扩散、混合时间准数以及单位体积能耗等的变化。对放大后的DPSTMM,在煤油/辛醇(体积比10:1)-醋酸-水体系中,应用串级萃取原理分析了实验测定的总效率,计算出了不同混合段数时的总传质系数K_(od)α。结果表明DPSTMM具有良好的流体力学性能和传质性能。     

INFLUENCE OF BATCH MIXING TIME AND BATCH GRAIN SIZE ON HOMOGENEITY OF A SODA-LIME-SILICA GLASS*

Density-spread determinations were made on a series of melts of a soda-lime-silica glass employing batches compounded from raw materials varying in particle size from 20- to 60-mesh to minus 200-mesh, which had been mixed by tumbling for one, ten, or thirty minutes. The two melting techniques employed were (1) melting for sixteen hours in a stationary platinum crucible at 1400°C. under conditions of even temperature distribution and consequently a minimum of convection mixing and (2) melting for four hours at 1400°C. in a rotating tilted crucible; this condition was intended to simulate convection mixing Under the experimental conditions employed, it was found that (1) batch mixing time has relatively little effect on the homogenizing rate, (2) homogenization increases rapidly with decrease in grain size, and (3) in all cases the 4-hour melting treatment with moderate mixing gives better homogeneity than sixteen hours melting time in a stationary crucible, this effect increasing with decrease in grain size. No significant difference in glass homogeneity resulted from three different methods of mixing, namely, tumbling, ball milling, and mixing in a muller-type mixer, although the homogenizing influence imposed probably was sufficient to mask any differences in uniformity of mixing that might have existed.     

金属板波填料板片上开孔孔型对气流径向混合的影响

在两相流工况下，对两种孔型板波填料作气流的径向分布性能的实验研究。提出用液气动量比来反映不同操作工况条件。对比结果表明，桥孔比圆孔更有利气流的径向扩散。