Design and Simulation Optimization for Hydrodynamic Fertilizer Injector Based on Axial-Flow Turbine Structure
This work involves the development of a hydrodynamic fertilizer injector (HFI), which uses an integrated axial-flow turbine (AFT) and a diaphragm pump to absorb liquid fertilizer. Three structural parameters—the number of impellers (M<sub>1</sub>), average number of blades per impeller (...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-03-01
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| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/6/2963 |
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| Summary: | This work involves the development of a hydrodynamic fertilizer injector (HFI), which uses an integrated axial-flow turbine (AFT) and a diaphragm pump to absorb liquid fertilizer. Three structural parameters—the number of impellers (M<sub>1</sub>), average number of blades per impeller (M<sub>2</sub>), and arrangement pattern (M<sub>3</sub>)—are considered, and 12 AFT designs are developed. Using a combination of CFD numerical simulations and hydraulic performance testing, the response of the AFT output power (<i>P</i>), blade negative pressure (<i>NP</i>), and fertilizer injection flow rate (<i>Q</i><sub>inj</sub>) to structural parameters and inlet pressure (<i>H</i>) is investigated. The results show that the normalized root mean square error between the simulated outlet flow rate (<i>Q</i><sub>s</sub>) and the measured flow rate (<i>Q</i><sub>m</sub>) is 5.1%, indicating high accuracy in the grid motion simulation method. <i>P</i> increases first and then decreases with the increase in impeller speed (<i>n</i>). The maximum <i>P</i> (<i>P</i><sub>max</sub>) ranges from 150.1 to 201.4 W. <i>P</i><sub>max</sub> increases with <i>H</i>, decreases with increasing M<sub>1</sub> and M<sub>2</sub>, and shows little change with M<sub>3</sub>. At <i>H</i> = 0.14 MPa, M<sub>1</sub> and M<sub>2</sub> have a significant influence, and at <i>H</i> ≥ 0.14 MPa, M<sub>1</sub> becomes the most significant factor (<i>p</i> < 0.05). Low-speed flow and negative pressure cavitation zones at the leading edge of the blade suction surface cause flow blockage and affect the lifespan of the AFT. These regions decrease in size as <i>H</i> increases but increase with M<sub>1</sub>. The negative pressure (<i>NP</i>) decreases as M<sub>2</sub> increases. When M<sub>1</sub>, M<sub>2</sub>, and M<sub>3</sub> are 2, 3, and identical (D33), the <i>P</i><sub>max</sub> of the AFT is maximized, increasing by 6.7% to 33.5% compared with those of the other combinations. The <i>Q</i><sub>inj</sub> of D33, D34, D43, and D44 at <i>H</i> = 0.12~0.18 MPa range from 288.6 to 847.3 L/h, which is 38.7% to 461.0% higher than that of domestic and international venturi injectors. When considering cavitation issues and the manufacturing cost of the AFT mold, D44 may be chosen. Although its <i>Q</i><sub>inj</sub> is 7.0% lower than that of D33, <i>NP</i> is reduced by 37.9%. These findings provide a basis for the development of the HFI with AFT as the driving unit. |
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| ISSN: | 2076-3417 |