【作者】 汪上飞；

【导师】 吴双应； 丁国光；

【作者基本信息】 重庆大学 ， 动力工程， 2007， 硕士

【摘要】 钛白粉是一种白色无机颜料,化学性质稳定,广泛应用于涂料、塑料、橡胶、油墨、纸张、化纤、陶瓷、日化、医药、食品等行业。在其工业生产中,存在圆盘洗涤工艺,通常需要大量的水对物料进行水洗操作。喷射器作为一种流体机械,在许多工业领域中都有应用,但较少应用于节水。本文着重对四川攀枝花兴中钛业公司生产钛白粉的用水工艺进行改进,将先前传统的圆盘洗涤,改为使用节水清洗元件的圆盘洗涤,并对节水清洗元件的性能进行了理论分析及实验研究,研究了影响节水清洗元件性能的主要因素,最后对节水清洗元件在圆盘洗涤工艺中的应用及经济效益进行了分析。本项研究提出的节水清洗元件,使用喷射器原理,利用压力水来引射空气,使气、水在混合室均匀渗混成气-水两相流,而两相流的音速大大地低于单相流,当流体从亚音速变为超音速时,要产生激波,使两相流进一步增压,达到容积流量和射流速度同时增大的效果,起到节水的作用。论文首先对节水清洗元件的节水性能进行理论分析。研究表明,节水性能可由喷射系数表征,喷射系数越大,节水效果越好,而影响喷射系数的主要因素,包括面积比、工作压力、引射压力及出口压力等。文中给出了这些影响因素改变时对于喷射系数影响的具体表达式,并分析了这些因素的影响大小。文中还建立了一套以水(工作流体)和空气(引射流体)为介质的节水清洗元件实验台,根据理论分析,初步拟定实验用的节水喷射器的几何尺寸、出入口通径、喉部通径、引射口大小;改变喷嘴出口直径和混合腔孔径,实验研究了节水喷射器基本参数对其性能的影响,并根据喷射系数得到最佳尺寸搭配,对节水清洗元件的结构进行了初步优化。最后,结合四川攀枝花兴中钛业钛白粉生产工艺的实际情况,根据圆盘洗涤工艺运行过程,将节水清洗元件应用于圆盘洗涤工艺中,并根据节水试验结果对节水清洗元件的应用效果进行了经济性分析。更多还原

【Abstract】 Titanium dioxide pigment （TiO₂） is a kind of white powder with high opacity, brilliant whiteness, excellent covering power and resistance to color change. These properties have made it a valuable pigment and opacifier for a broad range of applications in paints, plastic goods, inks and paper. During the production procedures of Titanium dioxide pigment, raw materials need washing and cleaning by much water in order to get rid of the impurities. As a fluid machine, ejector is widely applied in industries but few used as water-saving device. In this paper we are engaged in the performance analysis and experimental investigation of the ejector which is used as water-saving component in disc filter cleaning process within TiO₂ production procedures of Xingzhong Titanium Co. in Panzhihua, Sichuan province. By theoretical and experimental research, the main factors governing the performance of water-saving component are determined, and application and economy analysis of water-saving component in disc filter cleaning process are made.The water-saving component is on the basis of ejector theory of fluid dynamics knowledge. When the component works, it is injected with the pressure water as motive fluid and the air from surroundings as suction fluid, then water and air meet with each other and turn out to be gas-liquid two phase flow in the mixing section. While the speed of sound in two phase flow is much lower than it in single phase flow, that is to say that the subsonic flow, including motive fluid and suction fluid, turn out to be the supersonic flow, i.e. the gas-liquid two phase flow; when shock wave occurs, through which pressure of the two phase flow increase abruptly. Accordingly, when water get through the water-saving component, both the flow rate and the velocity of work fluid out of it increase, and the function of it comes into effect.Firstly, we theoretically analyze the performance of water-saving component, which depends on the entrainment ratio of it. The more the value of entrainment ratio of water-saving component is, the greater the effect upon water-saving is. The results show that there are many relations among entrainment ratio, ejector configuration and operating parameters, including area ratio, working pressure, ejecting pressure and outlet pressure. The expressions of parameters are obtained in this paper, and how the variables affecting are also analyzed.Secondly, test-bed of water-saving component is set up, with water as motive fluid and air as suction fluid. According to the theoretical performance analysis of water-saving component, the property parameters of it are studied and the configuration of it is designed. In the experiment investigation, we study that how the water-saving performance of ejector is affected by parameters, viz. the nozzle, the absorber, the mixing-chamber, and the diffuser, and the optimal performance of water-saving component is concluded. According to the optimal performance of water-saving component, the optimal configuration of it is made.Finally, according to the actual TiO₂ production procedures of Xingzhong Titanium Co., the water-saving component is experimentally applied in the disc filter cleaning process, and economy analysis of it in disc filter cleaning process is made.更多还原