| In recent years, the rural biogas construction has developed rapidly under the expanding of a series of benefit policies. However, residue fluid and sludge contains residual gas, resulting that the residue fluid and sludge can not be immediately removed in the process of using biogas digesters. And biogas digesters abandoned in rural areas is more common phenomenon. In order to solve the difficult problem of clearing away residue fluid and sludge, in this subject double channel-type slurry pump of family-size was designed combining with electricity for rural, biogas digesters structure,volume and the current status of removing residue fluid and sludge.In this subject, slurry pump was studied as the research object by hydraulic design of its whole flow field and flow components of the three-dimensional modeling and CFD numerical simulation. Its performance was predicted and analysised. The main work and research results obtained are as follows:1. According to the type of underground biogas structure and volume which is promote in Chinese rural areas, the design parameters and structure of the slurry pump was determined. The pump motor was placed on the surface of the digester, and the pump body sneaked into the slurry. Motor is 220 volts AC motor. The slurry pump was operated simply, safely, reliably and easily to move with light weight.2. How to determine the channel midline was the key technology in process of designing double channel pump. By comparing the change of two Archimedes spiral curvature, selection ruler of an equation of plan channel midline was given.3. A three-dimensional solid formation of the slurry pump flow passage components was presented by using Pro/Engineer software, which has a good three-dimensional shape function. It was fast and accurate to generate impeller channel midline by the method of inputting Archimedes spiral formula. Also solid formation of the impeller is more accurate too.4. In this subject, the influence of the three-dimensional design of the impeller was analysed combining with channel midline. During the process of solid modeling of the impeller, flow cross sections were easy to intersect in space, leading to modeling failure. Therefore only simple plane hydraulic design of the impeller can not guarantee the formation of the smooth inner channel. In this case three-dimensional solid modeling of the impeller can check its rationality. If the smooth flow channel can not be generated, the spatial placed angle of cross sections, the variation rule of flow channel cross-section area, and an equation of plan channel midline should be modified in turn. Finally the smooth impeller channel was got.5. The steady numerical simulation of the whole filed flow was carried out by using CFD technology, when the slurry pump was transporting water and solid-liquid two-phase medium. In order to obtain performance on the slurry pump that solid particle diameter and concentration affected, simulation was calculated in two conditions: the same transport of solid concentration with different particle diameter and the same transport of particle diameter with different solid concentration. Hydraulic properties changes and channel wear obtained through the internal flow processing and analysis with the numerical results. It also established theory base for further study of the slurry pumps.6. The studies suggested that the slurry pump designed in this subject met the given design parameters and performance requirements; the hydraulic design of the slurry pump was reasonable; double channel pump as slurry pumps met the requirement of removing residue fluid and sludge to the household biogas digesters; it has a great significance for the structure of the slurry pump to be promoted.
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