# Investigation on the Effect of Structural Parameters on Cavitation Characteristics for the Venturi Tube Using the CFD Method

^{1}

^{2}

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## Abstract

**:**

## 1. Introduction

_{2}photocatalytic degradation of tetracycline by using a Venturi tube and found that hydrodynamic cavitation had a positive role and can prevent photocatalytic particles from agglomeration. Boczkaj et al. [18] indicated that the hydrodynamic cavitation can reduce the total pollution load in the effluent from the production of bitumens in advanced oxidation processes. Thanekar et al. [19] demonstrated that hydrodynamic cavitation combined with ozone can be effectively used as pretreatment for improving the biodegradability of Dichlorvos (DDVP). Hence, with the development of such technologies, the Venturi tube has already been widely used in wastewater treatment because of its cavitation characteristics.

## 2. Materials and Methods

#### 2.1. Physical Model

_{in}is inlet diameter (mm).

#### 2.2. Mesh Generation

#### 2.3. Numerical Approach

_{m}, u, p donate mixed medium density, velocity, and pressure, respectively. x and the subscripts i, j, k represent the coordinate direction. μ

_{m}is dynamic viscosity of the mixture. μ

_{t}is turbulent viscosity of the mixture. δ

_{ij}is the Kronecker delta.

_{v}is the vapor density, α

_{v}is the vapor volume fraction, and v

_{j}is a velocity component in x

_{j}direction, R

_{e}and R

_{c}are the mass transfer rates correspond to the evaporation and condensation during the cavitation process respectively. In this study, the Rayleigh-Plesset model was applied and the Rayleigh-Plesset equation describing the growth of a gas bubble in a liquid is given by:

_{B}is the bubble radius, p

_{v}is the pressure in the bubble (assumed to be the vapor pressure at the liquid temperature), p is the pressure in the liquid surrounding the bubbler, ρ

_{l}is the liquid density, α

_{n}is a nucleation site volume fraction, F is an empirical factor depend on condensation and vaporization designed for different rates.

^{−5}for all equations. According to mass conservation, the mass flow rates of inlet and outlet were both checked to ensure they were equal.

#### 2.4. Testing System

^{3}h

^{−1}and a lift head of 30 m delivered water to the testing system. The flow rate through the pipe was measured by an electromagnetic flowmeter with an accuracy of ±0.3%. Two pressure gauges with an accuracy of ±0.4% were installed at the upstream and downstream sections to monitor the differential pressure through the Venturi tube. Two gate valves were installed to adjust the differential pressure between the inlet and outlet sections of the Venturi tube.

## 3. Results and Discussion

#### 3.1. Verification of the Simulation Method

#### 3.2. Effects of Contraction Angle on Cavitation Characteristics

#### 3.3. Effects of Diffusion Angle on Cavitation Characteristics

#### 3.4. Effects of Contraction Ratio on Cavitation Characteristics

## 4. Conclusions

## Author Contributions

## Funding

## Acknowledgments

## Conflicts of Interest

## References

- Zhang, J.X. Analysis on the effect of venturi tube structural parameters on fluid flow. AIP Adv.
**2017**, 7, 065315. [Google Scholar] [CrossRef] [Green Version] - Simpson, A.; Ranade, V.V. Modeling hydrodynamic cavitation in venturi: Influence of venturi configuration on inception and extent of cavitation. AIChE J.
**2019**, 65, 421–433. [Google Scholar] [CrossRef] - Pak, S.; Chang, K. Performance estimation of a Venturi scrubber using a computational model for capturing dust particles with liquid spray. J. Hazard. Mater.
**2006**, 138, 560–573. [Google Scholar] [CrossRef] [PubMed] - Zhao, C.; Zhu, Y.; Li, Y.; Liu, G.; Shang, T.; Zhu, J.A.; Jiao, T. Design and experimental of venturi in EGR system of turbocharged intercooled diesel engine. Trans. Chin. Soc. Agric. Eng.
**2013**, 29, 49–56. [Google Scholar] - Wang, X.J.; Tang, L.; Jiang, Z. Numerical simulation of Venturi ejector reactor in yellow phosphorus purification system. Nucl. Eng. Des.
**2014**, 268, 18–23. [Google Scholar] [CrossRef] - Quiroz-Pérez, E.; Vázquez-Román, R.; Lesso-Arroyo, R.; Barragán-Hernández, V.M. An approach to evaluate Venturi-device effects on gas wells production. J. Pet. Sci. Eng.
**2014**, 116, 8–18. [Google Scholar] [CrossRef] - Ghassemi, H.; Fasih, H.F. Application of small size cavitating venturi as flow controller and flow meter. Flow Meas. Instrum.
**2011**, 22, 406–412. [Google Scholar] [CrossRef] - Sun, Y.Q.; Niu, W.Q. Simulating the effects of structural parameters on the hydraulic performances of Venturi tube. Model. Simul. Eng.
**2012**, 2012, 458368. [Google Scholar] [CrossRef] - Ashrafizadeh, S.M.; Ghassemi, H. Experimental and numerical investigation on the performance of small-sized cavitating venturis. Flow Meas. Instrum.
**2015**, 42, 6–15. [Google Scholar] [CrossRef] - Lu, H.; Guo, X.; Li, P.; Liu, K.; Gong, X. Design optimization of a venturi tube geometry in dense-phase pneumatic conveying of pulverized coal for entrained-flow gasification. Chem. Eng. Res. Des.
**2017**, 120, 208–217. [Google Scholar] [CrossRef] - Manzano, J.; Palau, C.V.; Benito, M.D.A.; Guilherme, V.D.B.; Vasconcelos, D.V. Geometry and head loss in Venturi injectors through computational fluid dynamics. Eng. Agríc.
**2016**, 36, 482–491. [Google Scholar] [CrossRef] [Green Version] - Bethi, B.; Sonawane, S.; Potoroko, I.; Bhanvase, B.A.; Sonawane, S.S. Novel hybrid system based on hydrodynamic cavitation for treatment of dye waste water: A first report on bench scale study. J. Environ. Chem. Eng.
**2017**, 5, 1874–1884. [Google Scholar] [CrossRef] - Yi, C.; Lu, Q.; Wang, Y.; Wang, Y.; Yang, B. Degradation of organic wastewater by hydrodynamic cavitation combined with acoustic cavitation. Ultrason. Sonochemistry.
**2018**, 43, 156–165. [Google Scholar] [CrossRef] [PubMed] - Rajoriya, S.; Bargole, S.; George, S.; Saharan, V.K. Treatment of textile dyeing industry effluent using hydrodynamic cavitation in combination with advanced oxidation reagents. J. Hazard. Mater.
**2018**, 344, 1109–1115. [Google Scholar] [CrossRef] - Badmus, K.O.; Tijani, J.O.; Massima, E.; Petrik, L. Treatment of persistent organic pollutants in wastewater using hydrodynamic cavitation in synergy with advanced oxidation process. Environ. Sci. Pollut. Res.
**2018**, 25, 7299–7314. [Google Scholar] [CrossRef] [Green Version] - Kim, H.J.; Nguyen, D.X.; Bae, J.H. The performance of the sludge pretreatment system with venturi tubes. Water Sci. Technol.
**2008**, 57, 131–137. [Google Scholar] [CrossRef] - Wang, X.; Jia, J.; Wang, Y. Combination of photocatalysis with hydrodynamic cavitation for degradation of tetracycline. Chem. Eng. J.
**2017**, 315, 274–282. [Google Scholar] [CrossRef] - Boczkaj, G.; Gągol, M.; Klein, M.; Przyjazny, A. Effective method of treatment of effluents from production of bitumens under basic pH conditions using hydrodynamic cavitation aided by external oxidants. Ultrason. Sonochemistry.
**2018**, 40, 969–979. [Google Scholar] [CrossRef] - Thanekar, P.; Murugesan, P.; Gogate, P.R. Improvement in biological oxidation process for the removal of dichlorvos from aqueous solutions using pretreatment based on Hydrodynamic Cavitation. J. Water Process Eng.
**2018**, 23, 20–26. [Google Scholar] [CrossRef] - Hachino, K.; Sato, K.; Saito, Y. Inception and Dynamics of Traveling-Bubble-Type Cavitation in a Venturi. In Proceedings of the ASME/JSME 2003 4th Joint Fluids Summer Engineering Conference, Honolulu, HI, USA, 6–10 July 2003; pp. 279–285. [Google Scholar]
- Cai, J.; Huai, X.; Li, X. Dynamic behaviors of cavitation bubble for the steady cavitating flow. J. Therm. Sci.
**2009**, 18, 338–344. [Google Scholar] [CrossRef] - Abdulaziz, A. Performance and image analysis of a cavitating process in a small type venturi. Exp. Therm. Fluid Sci.
**2014**, 53, 40–48. [Google Scholar] [CrossRef] - Brinkhorst, S.; Von Lavante, E.; Wendt, G. Numerical investigation of cavitating Herschel Venturi-Tubes applied to liquid flow metering. Flow Meas. Instrum.
**2015**, 43, 23–33. [Google Scholar] [CrossRef] - Chen, G.; Wang, G.; Hu, C.; Huang, B.; Gao, Y.; Zhang, M. Combined experimental and computational investigation of cavitation evolution and excited pressure fluctuation in a convergent–divergent channel. Int. J. Multiph. Flow.
**2015**, 72, 133–140. [Google Scholar] [CrossRef] - Tomov, P.; Khelladi, S.; Ravelet, F.; Sarraf, C.; Bakir, F.; Vertenoeuil, P. Experimental study of aerated cavitation in a horizontal venturi nozzle. Exp. Therm. Fluid Sci.
**2016**, 70, 85–95. [Google Scholar] [CrossRef] [Green Version] - Long, X.; Zhang, J.; Wang, J.; Xu, M.; Lyu, Q.; Ji, B. Experimental investigation of the global cavitation dynamic behavior in a venturi tube with special emphasis on the cavity length variation. Int. J. Multiph. Flow.
**2017**, 89, 290–298. [Google Scholar] [CrossRef] - Zhu, J.; Xie, H.; Feng, K.; Zhang, X.; Si, M. Unsteady cavitation characteristics of liquid nitrogen flows through venturi tube. Int. J. Heat Mass Transf.
**2017**, 112, 544–552. [Google Scholar] [CrossRef] - Tang, P.; Li, H.; Issaka, Z.; Chen, C. Impact forces on the drive spoon of a large cannon irrigation sprinkler: Simple theory, CFD numerical simulation and validation. Biosyst. Eng.
**2017**, 159, 1–9. [Google Scholar] [CrossRef] - Brinkhorst, S.; Von Lavante, E.; Wendt, G. Experimental and numerical investigation of the cavitation-induced choked flow in a herschel venturi-tube. Flow Meas. Instrum.
**2017**, 54, 56–67. [Google Scholar] [CrossRef] - Long, X.P.; Wang, J.; Zuo, D.; Zhang, J.Q.; Ji, B. Experimental investigation of the instability of cavitation in veturi tube under different cavitation stage. J. Mech. Eng.
**2018**, 54, 209–215. [Google Scholar] [CrossRef]

**Figure 4.**Structural diagram of the experimental setup. 1. Electromotor 2. Pump 3. Electromagnetic flowmeter (50 mm) 4. Gate valve (50 mm) 5. Pressure gauge 6. Venturi tube 7. Pressure gauge 8. Gate valve (50 mm) 9. Water tank.

**Figure 6.**Average vapor volume fraction of cross-section form the throat in axial direction with different contraction angles.

**Figure 7.**Contour of vapor volume fraction in the throat and the diffusion section with different contraction angles, (

**a**) 15°, (

**b**) 30°, (

**c**) 45°, (

**d**) 60°.

**Figure 8.**Average vapor volume fraction of cross-section from the throat in the axial direction with different diffusion angles.

**Figure 9.**Contour of vapor volume fraction of the Venturi tube with different diffusion angles, (

**a**) 10°, (

**b**) 15°, (

**c**) 20°, (

**d**) 25°, (

**e**) 30°.

**Figure 10.**Average vapor volume fraction of a cross-section from the throat in the axial direction with different contraction ratios.

**Figure 11.**Contour of vapor volume fraction of the Venturi tube with different contraction ratios, (

**a**) 0.1, (

**b**) 0.2, (

**c**) 0.3, (

**d**) 0.4.

**Table 1.**Structural parameters of the Venturi model for computational fluid dynamics (CFD) analysis.

Group | α (°) | β (°) | γ |
---|---|---|---|

1 | 15, 30, 45, 60 | 20 | 0.28 |

2 | 30 | 10, 15, 20, 25, 30 | 0.28 |

3 | 30 | 20 | 0.2, 0.3, 0.4, 0.5 |

Scheme | Scheme 1 | Scheme 2 | Scheme 3 | Scheme 4 | Scheme 5 |
---|---|---|---|---|---|

Grid number | 101,342 | 154,683 | 201,679 | 284,813 | 349,866 |

Mass flow rate (kg s^{−1}) | 2.41 | 2.46 | 2.49 | 2.50 | 2.50 |

**Table 3.**Comparison between simulated and experimental values for mass flow rate under different differential pressures.

Inlet Pressure (MPa) | Outlet Pressure (MPa) | Mass Flow Rate | ||
---|---|---|---|---|

Measured (kg s^{−1}) | Simulated (kg s^{−1}) | Difference (%) | ||

0.15 | 0.10 | 1.64 | 1.70 | 3.66 |

0.20 | 0.10 | 2.38 | 2.49 | 4.62 |

0.25 | 0.10 | 2.43 | 2.53 | 4.12 |

0.30 | 0.10 | 2.42 | 2.54 | 4.96 |

0.35 | 0.10 | 2.43 | 2.55 | 4.94 |

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**MDPI and ACS Style**

Tang, P.; Juárez, J.M.; Li, H.
Investigation on the Effect of Structural Parameters on Cavitation Characteristics for the Venturi Tube Using the CFD Method. *Water* **2019**, *11*, 2194.
https://doi.org/10.3390/w11102194

**AMA Style**

Tang P, Juárez JM, Li H.
Investigation on the Effect of Structural Parameters on Cavitation Characteristics for the Venturi Tube Using the CFD Method. *Water*. 2019; 11(10):2194.
https://doi.org/10.3390/w11102194

**Chicago/Turabian Style**

Tang, Pan, Juan Manzano Juárez, and Hong Li.
2019. "Investigation on the Effect of Structural Parameters on Cavitation Characteristics for the Venturi Tube Using the CFD Method" *Water* 11, no. 10: 2194.
https://doi.org/10.3390/w11102194