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Preparation of Free-Surface Hyperbolic Water Vortices
Published on: July 28, 2023
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Flow characteristics and formation optimization of vortex ring air supply.
Zhixiang Cao1,2, Ruiping Wang2, Chao Zhai1,2
1State Key Laboratory of Green Building in Western China, Xi'an University of Architecture and Technology, Xi'an, People's Republic of China.
Indoor Air
|August 30, 2022
Summary
A novel vortex ring generator with a fresh air cavity significantly improves ventilation systems. This design minimizes ambient air entrainment, enhancing the fresh air ratio in confined vortex rings for more efficient air supply.
Area of Science:
- Fluid dynamics
- Mechanical engineering
- HVAC systems
Background:
- Vortex ring ventilation (VRV) uses stable vortex rings for air supply, reducing transport losses.
- However, vortex ring formation entrains ambient air, diluting the fresh air supply.
- Improving the fresh air ratio in VRV systems is crucial for efficiency.
Purpose of the Study:
- To develop and evaluate a vortex ring generator with a fresh air cavity.
- To investigate the impact of this design on fresh air ratio and mixing.
- To optimize the generator's dimensions for enhanced performance.
Main Methods:
- Development of a piston-orifice axisymmetric model with dynamic grid for air vortex ring generation.
- Experimental study of free vortex ring evolution to determine optimal parameters.
- Comparison of mixing ratios between free and confined vortex rings.
Main Results:
- The confined vortex ring generator achieved zero mixing ratio during formation.
- At 4.9 orifice diameters, confined vortex rings showed a 77.78% reduction in mixing ratio compared to free rings.
- Optimized fresh air cavity dimensions (inner diameter > X, outlet diameter > Y) showed minimal impact on vortex rings.
Conclusions:
- The proposed fresh air cavity design effectively reduces ambient air entrainment in vortex rings.
- This innovation significantly enhances the fresh air ratio in VRV systems.
- Optimized generator dimensions ensure efficient confined vortex ring formation and air supply.
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