HYDRODYNAMIC CAVITATION AND ITS APPLICATION IN FOOD INDUSTRY SAHLA.pptx

Hydrodynamic cavitation is an emerging technology with significant potential in the food industry. It involves the formation, growth, and collapse of vapor-filled cavities or bubbles in a liquid, triggered by variations in pressure. This process generates intense localized energy in the form of shock waves and high temperatures, which can be harnessed for various applications in food processing.

In the food industry, hydrodynamic cavitation is gaining attention for its efficiency in enhancing processes like mixing, emulsification, extraction, and microbial inactivation. Unlike conventional methods, it offers a more energy-efficient, environmentally friendly, and scalable approach to achieving high-quality results. By optimizing texture, flavor, and preservation, hydrodynamic cavitation holds promise for innovation in food processing, making it a key area of research and development.

1. HYDRODYNAMIC CAVITATION & IT’S APPLICATION IN FOOD INDUSTRY SAHLA PARVIN M K 23412MFT016 M.Tech Food Processing Technology Department of Dairy Science & Food Technology

2. INTRODUCTION The food industry is moving towards advanced technologies due to the demand for nutritious, minimally processed, and additive-free foods Consumer demand for high-quality, fresh-like foods with enhanced nutritional value is driving innovation in non-thermal methods There is increasing awareness of minimally processed, non-thermal foods with maximum nutrients and minimal calories Majority of consumers prefer non-thermal technologies for better nutritive and sensory qualities Unsurprisingly, one of those novel food processing technologies under explored is hydrodynamic cavitation (HC) Hydrodynamic Cavitation (HC) is emerging as a non-thermal, energy-efficient processing technology Athira et al.,2024

3. CAVITATION Cavitation : Formation, growth, and collapse of microbubbles or cavities in a liquid when the pressure falls below the vapor pressure of the liquid, releasing large amount of energy in milliseconds Energy : Causes high pressures ( 100-1000 bars ) and temperatures ( 1000-10,000 K ) at multiple locations in a reactor Types of Cavitation : Hydrodynamic - Caused by pressure difference in liquid flow due to changes in flow velocity Acoustic - Induced by ultrasound waves creating pressure differential Optical - Results from liquid bursts due to laser or high-intensity light Particle - Caused by subatomic particles, e.g., proton, producing cavitation in bubble traps Arya et al.,2023

4. HYDRODYNAMIC CAVITATION Vapor bubbles form in a liquid due to a significant pressure drop This occurs when the liquid passes through a flow constriction device (e.g., orifice, venturi), increasing velocity and kinetic energy, which causes a pressure drop When the pressure drops below the liquid's vapor pressure, cavities or bubbles are formed As the pressure recovers, these cavities grow and eventually collapse, releasing large amounts of energy into the surrounding liquid Arya et al.,2023

5. MECHANISM OF HYDRODYNAMIC CAVITATION Bernoulli’s Principle : Explains pressure reduction due to changes in velocity and pressure in a flow system where ρ is the density of the fluid, and denote the pressures at two points (upstream and downstream, respectively) and and are their corresponding fluid velocities Fluid Constriction - A constriction increases fluid velocity, causing a pressure drop Velocity & Pressure - At the throat of the constriction, velocity v₂ is highest, and pressure p₂ is lowest Vapor Bubble Formation - Vapor bubbles form when p₂ drops below the liquid’s vapor pressure at the given temperature Bubble Collapse - Downstream, pressure recovers, causing bubble collapse and releasing significant energy   Zheng et al.,2022

6. PHYSICOCHEMICAL EFFECTS Arya et al.,2023

7. HOT SPOT EFFECT Hot Spot Effect : Occurs when a cavity collapses, releasing heat and creating high-temperature environments Zones Around the Hotspot : Zone-I - Inside the bubble core, temperatures reach 5000-10,000 K, and pressure is 1000 atm. Free radicals form, causing molecular dissociation Zone-II - At the bubble-liquid interface, temperatures peak at 2000 K, with high microjet and shear turbulence during collapse Zone-III - In the bulk medium, temperature 300 K and pressure 1 atm are near normal J. Carpenter et al.,2017

8. Ranade et al.,2023

9. ORIFICE BASED HCR J Carpenter et al.,2017 The design of the orifice, including the number of holes, shape, and size , significantly affects the cavitation process The intensity of cavity collapse depends on the flow area, size, shape, and number of holes in the orifice Rapid Pressure Recovery - Sudden pressure recovery in an orifice leads to rapid collapse of cavities, resulting in intense effects Single-Hole Orifice - Cavities form only at the throat edge, leading to fewer cavities generated Multiple-Hole Orifice - Overcomes single-hole limitations by producing more cavities due to a larger flow perimeter

10. The microbial load decreased significantly with the increase in the inlet pressure, the number of holes on the orifice plate, and processing time The microbial load in the control sugarcane juice sample was observed 5.53 CFU/mL whereas the maximum microbial inactivation (3.3 CFU/mL,) was observed at 3.5 bar for 40 min   Component Description System Volume 15 L Cavitation Generation Orifice plate Orifice Plate Geometry Plate 1 1 orifice × 2 mm Plate 2 9 orifices × 1 mm Plate 3 17 orifices × 1 mm Orifice Flow Areas 3.14 mm² 7.065 mm² 13.35 mm² Inlet Pressures 2.5, 3.0, 3.5 bar Processing Times 10, 20, 30, 40 minutes

11. VENTURI BASED HCR J Carpenter et al.,2017 A venturi consists of three sections: a convergent section, a throat, and a divergent section Unlike an orifice, no sudden contractions or expansions occur in a venturi Smooth d ivergent section prevents sudden pressure recovery, allowing cavities to remain in low-pressure regions, essential for maximum cavity size Size and shape of the throat are crucial for maximizing cavity generation Venturis generate more cavitational events and enhance cavity life, making them preferred for certain applications

12. Experimental study of pathogenic microorganisms inactivated by Venturi-type hydrodynamic cavitation with different throat lengths – Dong et al.,2018 When raw water percentage was higher, killing rate gradually increased with increase in throat length-radius ratio; when raw water percentage was lower, killing rate was almost independent of throat length radius ratio Microjets and shock waves due to bubbles collapse could force cells of pathogenic microorganisms to generate cavitation damage Total Colony Count Throat length L (mm) Radius of throat R (mm) Throat length-radius ratio(L/R) 50 5 10 150 5 30 300 5 60 500 5 100 E.coli

13. VORTEX DIODES M ainly consists of a tangential port, cylindrical axial port, and a disc-shaped chamber (vortex diode) connecting the two ports Liquid enters the swirling chamber through a tangential port at an initial pressure Inside the chamber, the vortex diode creates a vortex, leading to highly accelerated flow The static pressure decreases toward the axial port, and at high tangential velocities, the core pressure falls below the liquid's vapor pressure This pressure drop leads to the formation of vapor-filled microcavities These cavities escape into a high-pressure region (axial port) where they collapse, releasing extreme temperatures and pressures

14. ROTATIONAL HCR Rotating impellers cause a local reduction in pressure, leading to cavitation when the pressure approaches vapor pressure A critical rotational speed exists, which is the threshold of cavitation generation As the impeller tip reaches critical speed, vapor cavities form, these collapse as the liquid flows away from the impeller Rotor speed, liquid flow rate, and pressure significantly affect the cavitation process and overall reactor performance A higher rotational speed produces higher tangential fluid velocity, which leads to higher turbulence intensity and lower system pressure Zheng et al.,2022

15. Effect of rotational speed Effect of flow rate Even though only 96.39% of  E. coli  was eliminated in 10 min at 2600 rpm, once the rotational speed was increased greater than 2600 rpm, 100% elimination rates were easily achieved in 10 min W hen the same rotational speed is constant, the cavitation intensity is concentrated at lower flow rates, leading to greater destruction effects, and vice versa

16. APPLICATIONS OF HYDRODYNAMIC CAVITATION

17. MICROBIAL CELL DISRUPTION

18. Arya et al.,2023

19. Comparative assessment of HTST, Hydrodynamic Cavitation & Ultrasonication microbial inactivation of raw milk – (Pegu et al.,2021) In HTST, 2.30 and 2.26 log reduction for TPC, and yeast and mold respectively Microbial log reduction in both US and HC treated milk samples increased with an increase in time and intensity Maximum log reduction of 0.93 TPC and 0.98 YM were obtained at 10 psi treated for 15 min by HC US showed a log reduction of 0.73 TPC and 0.79 YM at 400 W for 8 min Thus, the log reduction of micro organisms was in the manner of HTST > HC > US treatment Hydrodynamic Cavitation Ultrasonication

20. ENERGY EFFICIENCY In the HC system, energy efficiency increases with an increase in pressure and time The energy efficiency of the US system was less than 10% whereas in the HC system it is shown to have a maximum of 21.5% which indicates that the HC system has more quantity of energy that will effectively dissipate into the liquid medium and more energy for cavitational events In the cavitation phenomenon of HC, there is a higher generation of cavities than ultrasound which gave a cavity collapse of larger total volume making HC more efficient Treatment Treatment time (min) Energy efficiency % HYDRODYNAMIC CAVITATION 4 psi 5 10 15 4.3 7.83 10.05 6 psi 5 10 15 11.15 13.23 15.32 8 psi 5 10 15 15.52 16.73 17.48 10 psi 5 10 15 18.3 20.94 21.57 ULTRASONICATION 200 W 4 6 8 0.69 1.04 1.66 300 W 4 6 8 1.00 1.74 1.97 400 W 4 6 8 1.29 2.06 2.33 Pegu et al., 2021

21. FOOD ENZYME INACTIVATION

22. Effect of hydrodynamic cavitation (HC) processing on pectin methyl esterase (PME) inactivation kinetics in orange juice at different time and temperatures – (Arya et al.,2021) The inactivation of PME increased with increased temperature and also with an increased treatment time of HC PME is a thermostable enzyme; therefore, the role of high- temperature cavitation as an effective treatment in inactivating PME in orange juice processing was studied by increasing the temperature from 40℃ to 70℃ at different times conditions varied from 2 to 8 minutes Freshly squeezed and unprocessed orange juice showed a PME activity of 100% At every condition, PME activity was decreased with increasing time of HC as well as temperature

23. DISINFECTION OF WATER

24. CAVITATING DISINFECTING HAND PUMP

25. HOMOGENIZATION

26. Comparative assessment of Hydrodynamic cavitation(HC) and Ultrasonication(US) on microstructure of fat globules in raw milk Pegu et al.,2021 Fat globule count (HC) Fat globule count (US) Diameter of fat globule (HC) Diameter of fat globule (US)

27. Particle size distribution (PSD) of MPC dispersions prepared using conventional high-shear mixing indicated that complete rehydration of MPC powders was not achieved, with an average value of 21.17 μ m In contrast MPC dispersions subjected to HC had a PSD indicative of complete rehydration, with an average value of 0.45 μ m   Undissolved particles Gradual dispersion Complete hydration

28. LIMITATIONS OF HYDRODYNAMIC CAVITATION Munoz et al.,2023

29. CONCLUSION Hydrodynamic cavitation (HC) is widely acknowledged as a promising green approach for enhancing various production and processes, such as water treatment, sludge pretreatment,  emulsification , and food processing Although it shows more potential for industrial use than other technologies like ultrasound, the widespread commercial adoption of HC remained limited even after three decades of development Hydrodynamic cavitation holds great potential for revolutionizing the food industry by improving processes like emulsification, homogenization, and microbial inactivation Even though its adoption in industries is hindered by factors such as technological immaturity, high initial costs, operational complexity, competition with established technologies and a lack of awareness Scaling up HC systems from laboratory settings to industrial production is challenging. The effects observed at small scales are difficult to replicate consistently at larger volumes As the technology matures and more successful case studies emerge, it's likely that HC will see greater adoption in the future

30. REFERENCES Athira, V., Nair, U. A., Reddy, N. B. P., Khasherao, Y. B., & Sinija, V. R. (2024). 12 Hydrodynamic Cavitation and Its Applications in.  Non-Thermal Technologies for the Food Industry: Advances and Regulations , 184 Arya, S. S., More, P. R., Ladole, M. R., Pegu, K., & Pandit, A. B. (2023). Non-thermal, energy efficient hydrodynamic cavitation for food processing, process intensification and extraction of natural bioactives: A review.  Ultrasonics Sonochemistry , 106504. Doltade, S. B., & Pandit, A. B. (2022). Novel hydrodynamic cavitation based hand pump for disinfection of groundwater.  Environmental Quality Management ,  32 (1), 473-482 Ranade, V. V., Bhandari, V. M., Nagarajan, S., Sarvothaman, V. P., & Simpson, A. T. (2022).  Hydrodynamic Cavitation: Devices, Design and Applications . John Wiley & Sons Zheng, H., Zheng, Y., & Zhu, J. (2022). Recent developments in hydrodynamic cavitation reactors: Cavitation mechanism, reactor design, and applications.  Engineering ,  19 , 180-198. Arya, S. S., Sawant, O., Sonawane, S. K., Show, P. L., Waghamare, A., Hilares, R., & Santos, J. C. D. (2020). Novel, nonthermal, energy efficient, industrially scalable hydrodynamic cavitation–applications in food processing.  Food Reviews International ,  36 (7), 668-691 Pegu, K., & Arya, S. S. (2021). Comparative assessment of HTST, hydrodynamic cavitation and ultrasonication on physico-chemical properties, microstructure, microbial and enzyme inactivation of raw milk.  Innovative Food Science & Emerging Technologies ,  69 , 102640 Asaithambi, N., Singha, P., Dwivedi, M., & Singh, S. K. (2019). Hydrodynamic cavitation and its application in food and beverage industry: A review.  Journal of Food Process Engineering ,  42 (5), e13144 Gregersen, S. B., Wiking, L., Metto, D. J., Bertelsen, K., Pedersen, B., Poulsen, K. R., ... & Hammershøj, M. (2020). Hydrodynamic cavitation of raw milk: Effects on microbial inactivation, physical and functional properties.  International Dairy Journal ,  109 , 104790. Carpenter, J., Badve, M., Rajoriya, S., George, S., Saharan, V. K., & Pandit, A. B. (2017). Hydrodynamic cavitation: an emerging technology for the intensification of various chemical and physical processes in a chemical process industry.  Reviews in Chemical Engineering ,  33 (5), 433-468. Soyama, H. (2021). Luminescence intensity of vortex cavitation in a venturi tube changing with cavitation number.  Ultrasonics sonochemistry ,  71 , 105389 Dong, Z., & Qin, Z. (2018). Experimental study of pathogenic microorganisms inactivated by venturi-type hydrodynamic cavitation with different throat lengths. In  Journal of the Civil Engineering Forum Volume  (Vol. 4, No. 3) Sun, X., Wang, Z., Xuan, X., Ji, L., Li, X., Tao, Y., ... & Chen, S. (2021). Disinfection characteristics of an advanced rotational hydrodynamic cavitation reactor in pilot scale.  Ultrasonics sonochemistry ,  73 , 105543 Pathania, S., Ho, Q. T., Hogan, S. A., McCarthy, N., & Tobin, J. T. (2018). Applications of hydrodynamic cavitation for instant rehydration of high protein milk powders.  Journal of Food Engineering ,  225 , 18-25