Analysis Of Energy And Internal Flow Characteristics Of An Open Inlet Axial Flow Pump Device

Open inlet channel Axial flow pump device has been applied in agricultural irrigation,water supply and waterlogging drainage projects in China in recent years because of its simple structure,convenient installation and maintenance,etc.This thesis studies the internal flow and energy characteristics of open inlet channel Axial flow pump device,and explores the impact of key factors of open inlet channel on the hydraulic performance of the device through orthogonal test.This thesis first uses software such as ANSYS CFX and Solid Works to study the internal flow characteristics of an open inlet channel axial flow pump device through three-dimensional numerical calculations,and builds a test bench for experimental verification to explore the hydraulic performance and streamline conditions of each part.Subsequently,a multi factor orthogonal optimization study was conducted on the open inlet channel,and the following conclusions were drawn:（1）When the inlet flow rate of the inlet channel in Q=6 L/s～13 L/s,the efficiency curve of the pump device is roughly in line with the quadratic function relationship,reaching the highest efficiency at the design condition（Q=13 L/s）with an efficiency of 83.29%and a head of 0.618m;as the flow rate increases,the efficiency drops sharply;the head decreases gradually with the increase in flow rate,from 1.973m to 0.252m,and in Q=8 L/s fluctuates and the head decreases to 0.830m.（2）The uniformity of flow velocity distribution and velocity-weighted average angle distribution curves at the impeller inlet of the integrated open inlet axial flow pump device show that the flow pattern at the impeller inlet has a strong correlation with the flow conditions,and the flow distribution is not uniform under the small flow conditions（Q=6L/s～9 L/s）.Under the high flow condition（Q=14 L/s～16 L/s）,the axial and radial distribution of water flow is more uniform,the highest uniformity of flow velocity distribution is 91.985%,and the highest velocity weighted average angle is 85.807°.（3）Open inlet channel axial flow pump device A1 section open inlet channel flow channel front and flow channel back velocity,pressure gradient more,the middle section of the flow channel side wall at the same time there is a low-speed zone and high-speed zone,the subsequent flow velocity and pressure distribution;A2 section in the small flow conditions on the upper left and right sides of the flow channel flow velocity is low,the bottom of the flow channel flow velocity is not uniform,the right side of the flow velocity is higher,with the flow rate increases,the flow velocity distribution on the left and right sides of the flow channel tends to be uniform;The flow line at the back wall of the A3section inlet channel is dense,and the flow line at the bottom of the back wall collides with the upper return flow at the flapper pipe and converges to the inlet of the flapper pipe.The flow line is affected by the impeller rotation in the impeller area,and the flow direction is deflected,and the flow is divided into two streams in the inner side of the outlet bend and the outer side of the outlet bend,and some of the streams are crossed in the middle of the pipe,and the flow pattern is poor.（4）The orthogonal design was carried out for five parameters of the open inlet channel design:back wall distance L₁,overhang height H_B,pool width B,horn pipe height H_L,and horn pipe inlet diameter D_L.L₁₆（4⁵）orthogonal scheme was selected,and the efficiency of each group was calculated numerically,and the effect of each influencing factor on the efficiency was obtained by using the extreme difference analysis method:horn pipe inlet diameter D_L>overhang height H_B>pool width B>horn pipe height H_L>back wall distance L₁.pool width B>horn tube height H_L>back wall distance L₁.where the horn tube inlet diameter D_L is the key factor,the overhang height H_B,pool width B,horn tube height H_L is the general factor,and the back wall distance L₁ is the secondary factor.Compared with the original solution,the efficiency of the optimized design working condition is improved by0.50%,and the efficiency of the high flow working condition is improved by 1.28%.