Study On Characteristics Of Internal Flow In An Induced Flow Diaphragm Pump

As oil spill accidents occur at sea frequently, recently more and more attention is paid to prevent and recover the oil spill all over the world. Considering the way of recovering spill oil and the characteristics of waste oil, oil spill pumps should characterized by compact structure, light weight, large flow rate. It can translate fluid with solid particles or high viscosity, work continuously, be operated with no-load and not break down with overload. The diaphragm pump is adequate for oil spill recovery. However domestic pumps featured heavy structure and low handling capacity, and foreign technology is seriously blocked. Therefore the development of new diaphragm pumps ,which fitted national condition of China, with low price and high flow rate has become a series problem to be solved. Diaphragm pumps which use the induced flow principle with high volumetric efficiency would be more adaptable to translate marine spill oil.Based on basic principles of fluid mechanics, this paper established the theoretical model of the induced flow diaphragm pump, solved the differential equations and obtained the flow mechanism in the pump. It is clear that the course work of induced flow pumps was devided into powered flow and induced flow. In the powered flow phase, part of flow is saved into resilient chamber when the velocity of fluid discharged by piston is larger than the flow velocity in the discharged pipe, then the fluid is released to improve the velocity of flow as the velocity of piston decreases. In the induced flow phase, the fluid outside was discharged under the inertia force of the flow in discharge pipe. The model of theoretical construct of induced flow pumps was established, the affect of the velocity source was involved, the open and close of the valve was judged by In-Form, the MOF file which assign objects'moving was compiled and finally the working characteristic of the induced flow principle was studied by numerical simulation. The results show that the induced flow is exist and the volumetric efficiency reaches 200% theoretically. Besides, the reasonable numerical simulation method was checked by the same curves of numerical simulation and theoretical derivation. Using the same numerical simulation method, the interior flow characteristics of a real induced flow reciprocating pump was simulated. Results show that the volumetric efficiency is 127% and the interior flow is apparently rasymmetric. The induced flow is produced mainly in the channel beside the discharge pipe, and flow loss in pump is very large. By the numerical simulation of the flow in the induced flow reciprocating pump with symmetric construction, it can be showed that the interior flow loss decreases obviously and induced flow effect is enhanced. The study results have some theoretical guidance value on the optimal design of induced flow diaphragm pumps.