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Air entrainment and pressure drop in low-cost ejectors
Daniel D Lima1, Iran E Lima Neto1
1Universidade Federal do Ceará/UFC, Departamento de Engenharia Hidráulica e Ambiental, Av. Humberto Monte, s/n, Campus do Pici, Bl. 713, 60451-970 Fortaleza, CE, Brazil.
Anais Da Academia Brasileira De Ciencias
|November 18, 2020
Summary
Low-cost PVC ejectors demonstrate effective air entrainment for aeration and mixing applications. Despite a 3-fold decrease with flow meters, they offer a better benefit-cost ratio than conventional ejectors.
Area of Science:
- Fluid dynamics
- Chemical engineering
Background:
- Ejectors are crucial for fluid transport and mixing.
- Low-cost alternatives are sought for industrial applications.
- Understanding air entrainment is key for efficient aeration.
Purpose of the Study:
- To experimentally investigate air entrainment and pressure drop in low-cost PVC ejectors.
- To compare the performance of these ejectors with conventional designs.
- To evaluate their suitability for aeration and mixing applications.
Main Methods:
- Fabrication of low-cost ejectors from PVC bars.
- Insertion into a 25 mm PVC T-junction.
- Experimental measurement of water and air flow rates.
- Analysis of pressure drop and entrainment ratios.
Main Results:
- Similar hydraulic behavior across different ejector designs.
- Linear relationship observed between water and air flow rates.
- A 3-fold reduction in air entrainment when a rotameter was used.
- Maximum air-water entrainment ratio of 1.7.
- Pressure drop reached approximately 80% of upstream pressure.
- Gas-liquid flow yielded a 2.5x higher entrainment ratio than single-phase flow.
Conclusions:
- Low-cost PVC ejectors offer a favorable benefit-cost ratio for aeration and mixing.
- Gas-liquid flow enhances entrainment compared to single-phase flow due to density and turbulence.
- These ejectors present a viable alternative to conventional designs in various water treatment and mixing processes.
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