液下螺旋离心沼液沼渣泵研究与开发

发布时间：2018-04-19 12:19

本文选题：沼液沼渣 + 螺旋离心泵　；参考：《兰州理工大学》2013年硕士论文

【摘要】：我国农村沼气池数量位居世界第一。但是随着农村劳动力的转移,农村沼气工程面临主要困境仍是出料难、搅拌难。因此,本课题提出使用液下螺旋离心泵输送沼液沼渣,其研发对农村沼气池工程可持续发展具有重大的现实意义,并且有广阔的应用前景。首先,根依据我国农村地区大力推广的地下式沼气池结构形式以及容积,确定出了泵设计参数。考虑到沼气发酵残留物、农户用电容量、使用安全性等重要因素,泵的结构形式为叶轮为螺旋叶轮,采用220v1.5kw单相异步电动机作动力机构置于沼气池外,泵潜入沼液内工作。其次,采用广泛使用的速度系数法、相似换算法,开展了螺旋离心沼液沼渣泵叶轮和压水室的水力设计。在水力设计中,考虑到了沼气池料液中含有大量纤维杂质、颗粒等固体悬浮物的特性,力求螺旋离心沼液沼渣泵具有良好的水力性能及其通流能量。再其次,基于PRO/E软件对螺旋离心沼液沼渣泵整体建模。针对各计算域的结构特点,并结合网格划分的要求,采用ICEM-CFD软件并选用适应性强的四面体结构化网格,对计算域作网格划分。最后,开展螺旋离心沼液沼渣泵内部流场数值模拟。针对沼液沼渣含有大量纤维杂质、颗粒等固体悬浮物,其内残存沼气、有毒、难闻、成分不明的气体,以及沼渣沼液中残留的纤维杂质、颗粒等固体悬浮物形状不规则,将沼渣看作粒径均匀的球形颗粒,且固体颗粒直径分布在0.2～5mm之间,而颗粒半径在2～3mm范围内的颗粒占60%以上研究了物料的颗粒直径3mm固相体积浓度Cv为50%条件下,对泵性能影响规律；研究了设计工况下,颗粒直径3mm固相体积浓度Cv分别为10%、20%、30%、40%、50%、60%、70%和固相体积分数分为50%固相颗粒中值粒径d分别为1、2、3、4、5mm的时,对泵扬程、效率和轴功率的影响规律。研究表明： (1)清水介质下螺旋离心沼液沼渣泵的流量Q=9.5m3/h时,扬程为H=5.31m,效率为,7=61.86%,达到了设计要求。 (2)泵输送颗粒直径3mm固相体积浓度Cv为50%物料时,与输送清水比较,在设计流量9.5m3/h时,扬程下降了约lm,效率下降了约4%,而轴功率增加了约O.1kw。 (3)颗粒直径和固相体积分数分对泵性能有明显的影响,尤其固相体积分数较高或相同固相体积分数分较大固相颗粒粒径,都能影响泵扬程和效率。且固相体积分数较高时,轴功率较快上升,但轴功率的最大值未超过泵的配套功率1.5KW。 (4)螺旋叶片碰撞、摩擦主要部位是在螺旋叶片的背面附近和离心叶片的出口工作面附近。
[Abstract]:The number of rural biogas digesters in China ranks first in the world.However, with the transfer of rural labor force, the main dilemma of rural biogas engineering is still difficult to discharge materials and stir.Therefore, this paper puts forward that the research and development of biogas dregs with submerged helical centrifugal pump is of great practical significance for the sustainable development of rural biogas digesters, and has a broad application prospect.Firstly, the pump design parameters are determined according to the structure and volume of underground biogas digesters popularized in rural areas of China.Considering the important factors such as biogas fermentation residue, household electric capacity, safety in use, the structure of the pump is as follows: the impeller is a spiral impeller, the 220v1.5kw single-phase asynchronous motor is used as the power mechanism and is placed outside the biogas digester, and the pump sneaks into the biogas liquid to work.Secondly, the hydraulic design of impeller and water chamber of biogas residue pump with spiral centrifugal biogas liquid is carried out by using the widely used velocity coefficient method and similar conversion method.In hydraulic design, considering that there are a lot of fiber impurities and particles in the biogas digester, the biogas slag pump with screw centrifugal biogas liquid has good hydraulic performance and flowing energy.Secondly, based on PRO/E software, the whole model of biogas sludge pump with screw centrifugal biogas liquid is established.According to the structural characteristics of each computing domain and the requirements of grid division, the computational domain is meshed with ICEM-CFD software and tetrahedral structured grid with strong adaptability.Finally, numerical simulation of internal flow field of biogas sludge pump with helical centrifugal biogas liquid is carried out.In view of the fact that biogas residue contains a large amount of fiber impurities, particles and other solid suspensions, the residual biogas, toxic, unsmelling and unknown gases, as well as the fibrous impurities remaining in the biogas, particles and other solid suspended solids, are irregular in shape.The biogas residue was regarded as a spherical particle with uniform particle size, and the diameter of the solid particle was distributed between 0.2~5mm, and the particle radius in the range of 2~3mm was more than 60%. The particle diameter, 3mm, solid phase volume concentration (CV) of the material was 50%.The effect of particle diameter 3mm solid volume concentration (CV) on pump lift, efficiency and axial power was studied when the particle diameter 3mm solid volume concentration CV was 10% and 20%, respectively, when the solid phase volume fraction was 50% and the solid phase volume fraction was 50%, the median particle diameter d was 1 ~ 2 ~ 3 ~ 3 ~ 4 ~ 5 mm, respectively.Research shows that:(1) the flow rate Q=9.5m3/h of the helical centrifugal biogas sludge pump in clear water medium is 5.31 m, and the efficiency is 61.86 m, which meets the design requirements.(2) when the volume concentration of 3mm solid phase is 50%, when the pump conveys 50% solid volume concentration of particles, compared with the pure water, the lift decreases by about lm, the efficiency decreases by about 4 and the shaft power increases by about 0.1 kW when the design flow rate is 9.5m3/h.(3) the particle diameter and solid volume fraction have obvious influence on the pump performance, especially the higher solid volume fraction or larger solid particle size at the same solid volume fraction can affect the pump lift and efficiency.When the volume fraction of solid phase is high, the axial power increases rapidly, but the maximum value of the axial power does not exceed the matching power of the pump 1.5kW.The main parts of the friction are near the back side of the spiral blade and the exit face of the centrifugal blade.
【学位授予单位】：兰州理工大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TH38

【参考文献】