| Axial flow forced circulation pumps are widely used in industries,agriculture,and other fields due to their simple structure and convenient use.The research object of this article can directly adjust the motor to achieve bidirectional water supply,which has better application value.In this paper,the forward and reverse operation of bidirectional Axial-flow pump is numerically calculated and experimentally analyzed.First,a three-dimensional model is established,using SST k-ω Turbulence model and Reynolds time averaged N-S equation are used to compare and analyze the internal flow characteristics and hydraulic performance of the Axial-flow pump under different inlet directions through three-dimensional flow numerical calculation.The research results show that:(1)When the inlet flow rate of forward operation is 11.5L/s(Qd),the efficiency is relatively optimal,with a corresponding head of 0.53 m and an efficiency value of 57.50%.When the inlet flow rate is 9.5L/s(Qd),the hydraulic performance of reverse operation is relatively optimal,with a corresponding head of 0.65 m and an efficiency value of 59.65%.Under the design flow rate of 11.5L/s(Qd)in forward operation,the efficiency value of forward operation is 2.32% higher than that of reverse operation,and the difference becomes more obvious as the flow rate increases(2)Under forward operating conditions,the uniformity of flow velocity in the inlet channel is relatively high,with an average of 87.90%.The velocity weighted average angle is also relatively good,with an average of 87.07°.The inlet channel has good inlet conditions.The uniformity of flow velocity at the outlet of the guide vane increases with the increase of flow rate,and remains stable when the inlet flow rate is 14.5L/s;Under reverse operating conditions,the uniformity of flow velocity in the inlet channel is not as good as in the forward direction,with an average of 60.37%.Its velocity weighted average angle also remains within a certain range,with an average of 64.11 °.The uniformity of flow velocity at the outlet of the guide vane increases with the increase of flow rate,and remains within a certain range when the inlet flow rate is 10.5L/s.The speed weighted average angle range is between 68%-71%,and the difference in speed weighted average angles for each flow rate is small.(3)The positive operation of two-way Axial-flow pump was tested,and the results showed that the difference between the head collected in the test results and the numerical calculation head was large at the inlet flow of 5.5L/s-8.5L/s,and the difference was small at the inlet flow of 9.5L/s-13.5L/s,with the maximum difference of less than0.05m;The efficiency curve trend of the Axial-flow pump obtained from the test is basically the same as that obtained from the numerical calculation.Its efficiency value has a small difference at the inlet flow of 5.5L/s-11.5L/s,and a large difference at the inlet flow of 11.5L/s.The difference value of the highest efficiency point is about 0.31 percentage points,which verifies the results of the numerical calculation.(4)Install a deflector at the 90° angle of the outlet pipe in the forward operation,set three installation positions,and conduct numerical calculation of the Axial-flow pump model under different installation positions.The results show that the head of the Axial-flow pump in the forward operation of Scheme III reaches 0.54 m,and the efficiency is increased to 58.45%.Compared with the original position,the head is increased by 1.6%,and the efficiency is increased by 1.6%.The efficiency of the axial flow pump in the reverse operation of Scheme I is improved most significantly,with the efficiency value of 59.25%,Compared to the original scheme,its efficiency has increased by 7.3%,and the corresponding head is also the highest among all schemes,which is0.38 m.Its head has increased by 7.4%. |
