Optimization Design And Experimental Research On Submersible Mining Pump

With the booming industry of mining, submersible mining pump used in pumping domestic water containing sand,slag and other solid material increased year by year. Because of the special application occasion, the fluid parts are prone to erosion if design by pure water theory, which specialized in short life-span and low efficiency. To solve this problem, it is not only the high-performance wear-resistance materials is needed, but also the hydraulic design according to the two-phase flow theory. Therefore, this paper optimize the hydraulic design from the two-phase flow theory. The main research work and results are as follows:1. According to the two-phase flow theory of "import plug" and "export pumping" raised by Cai Bao-yuan, three main factors: inlet blade attack angleΔβ₁, outlet blade angleβ₂ and number of blades Z, were chosen to pursue orthogonal test. Nine test schemes were acquired by choosing 3 levels to the parameters stated above by using L₉ (3⁴) orthogonal table.2. Single phase pure water and solid-liquid two-phase flow simulation were carried out according to the nine scheme defined by orthogonal test. Compared with single phase simulation, the head and power dropped in two phase simulation. The outlet blade angleβ₂ and number of blades Z were different at their best schemes from the range calculation and histogram plot.3. Through blank column range analysis in the orthogonal test, the minor factors such as blade wrapping angleφ, impeller outlet diameter D₂ which could be adjusted according to actual situation without affecting the pump test results is acquired.4. Small solid particles concentrated on the impeller pressure side, move to the out peripheral along the pressure side, and exit at the impeller outlet with a small flow angle. Some particles in the departure of the impeller pressure side collide with the blades pressure side, and increases the impeller erosion. Therefore, in the design of solid-liquid two-phase flow pump, the outlet blade angleβ₂ should not be too large.5. The decreasement ofβ₂ could improve the pump shaft power characteristics, reduce the occurance of motor failure due to overload and improve the pump steability characteristics. The two-phase flow theory and shaft power saturation characteristics are unified at this point. 6. Through the comparsion of full and non-full flow field simulation, it is discovered that the wear ring leakage and disc friction loss has a major influence on pump efficiency. The model pump test shows that the full flow field simulation is more close to experimental results.7. Based on Fluent and orthogonal tests, when the two phase theory was applied in the optimization design of BQS20-40-5.5 pump, the design point efficiency is higher than the national standards, and thus the optimization purpose is achieved.