Effect Of Hydrodynamic Cavitation Research Articles

Effect of Hydrodynamic Cavitation and Drying Technique on Moisture Sorption Isotherm and Structural Properties of Egg White Protein Hydrolysate Powder

Effect of Hydrodynamic Cavitation and Drying Technique on Moisture Sorption Isotherm and Structural Properties of Egg White Protein Hydrolysate Powder

Preliminary analysis: Effect of a rotary generator of hydrodynamic cavitation on rheology and methane yield of wastewater sludge

Slightly acidic (pH 5.1) waste sludge with 4.7 % Total Solids (TS) was treated on a laboratory scale pined disc rotary generator of hydrodynamic cavitation (PD RGHC). Influence of four rotor discs with different number of cavitation generation units (CGUs) was investigated: 8-pins, 12-pins, 16-pins and 8-prism elements. The effect of hydrodynamic cavitation (HC) was investigated by analyzing rheological properties, surface tension, dewaterability, and particle size distribution. After subjecting the sludge to 30 cavitation passes, the dewatering ability of the sludge significantly decreased, resulting in a more than two-fold increase in Capillary Suction Time (CST). All regimes were successful in disintegrating particles to smaller sizes. A slight increase of sludge surface tension was measured post cavitation. Cavitated samples displayed a zero-shear viscosity, in contrast to the untreated sample, where viscosity noticeably increased as shear stress decreased. HC did not improve methane yield. Statistically significant correlations between physio-chemical properties and apparent viscosity at low shear stress were identified. Although there were no discernible statistical differences in sludge characteristics, some trends are visible among investigated CGU designs and warrant further research.

Insight into the Effects of Hydrodynamic Cavitation at Different Ionic Strengths on Physicochemical and Gel Properties of Myofibrillar Protein from Tilapia (Oreochromis niloticus).

Effects of different ionic strengths (0.2, 0.4, and 0.6 mol/L) and different hydrodynamic cavitation (HC) treatment times (0, 1, 2, 3, and 4 min) on the conformation and gel properties of tilapia myofibrillar proteins (TMP) were investigated. The results showed that the solubility of TMP was significantly enhanced (p < 0.05) with the increase in NaCl concentration, and the gel characteristics were significantly improved. After HC treatment of TMP, the average particle size was significantly reduced (p < 0.05) and solubility was significantly enhanced (p < 0.05) with the increase in treatment time, the internal hydrophobic groups and reactive sulfhydryl groups were exposed. The intrinsic fluorescence spectra showed the unfolding of the spatial tertiary structure of proteins, and the circular dichroism spectroscopy showed the significant reduction in the content of α-helix in the secondary structure of the proteins (p < 0.05). In addition, the WHC and gel strength of the TMP heat-induced gels were enhanced, which improved the microstructure of the gels, and scanning electron microscopy showed that the gel network of the TMP gels became denser and more homogeneous. Dynamic rheology results showed that HC treatment resulted in a significant increase in the final G' and G" values of TMP. In conclusion, HC treatment was able to improve the physicochemical structure and gel properties of TMP at different ionic strengths. This study presents a novel processing technique for the quality maintenance aspect of salt-reduced surimi gel products.

The effect of hydrodynamic cavitation on isomerization of hop alpha-acids, wort quality and energy consumption during wort boiling

Wort boiling is one of the most energy-intensive steps in beer production because the isomerization of hop alpha-acids (AA) into iso-alpha-acids (IAA) is a time and energy-consuming process. Acceleration of this process by hydrodynamic cavitation (HC), created by a Venturi tube cavitation nozzle, at temperatures below the boiling point, has been tested on a pilot scale. The results show that HC accelerated AA isomerization at all temperatures tested (70–90 °C). The highest HC powered isomerization yield was achieved at 90 °C. However, some quality parameters of the wort were not satisfactory (dimethyl sulphide content, hot break) and therefore the process was extended by a final short boil (10 min). This led to a wort comparable to that obtained after the traditional boiling process (100 °C, 90 min) with a simultaneous 33% energy savings.

Effect of Orifice Induced Hydrodynamic Cavitation on the Properties of Waste Activated Sludge

Exploring alternative methods to reduce the quantity of wastewater sludge and improve its characteristics is among the prioritized subjects in the field of sludge management. Hydrodynamic cavitation, commonly employed for water and wastewater treatment, also holds the potential for utilization as a pre-treatment method for sludge. In the presented study, the excess sludge obtained from the wastewater treatment facility of a food and beverage manufacturing factory was collected and disintegrated with a orifice-induced hydrodynamic cavitation unit. According to the data obtained, the highest cavitation performance was achieved under the condition where the cavitation number was set to 0.3. In addition, hydrodynamic cavitation performed under the optimum operating conditions, significantly increased the solubility of waste activated sludge. The results showed that the soluble chemical oxygen demand concentration, which was initially determined as 382 mg/l, reached 3,068 mg/l end of the cavitation. 64% of the total Kjeldahl nitrogen and 60% of the total phosphorus of waste-activated sludge were converted into soluble forms by the effects of hydrodynamic cavitation. Moreover, the results of the microbial study indicated that removal rates of indicator bacteria varied between 94% and 99%.

The effect of non-thermal hydrodynamic cavitation process on structural and function properties of casein protein

The effect of hydrodynamic cavitation (HC) on protein functionality is an emerging area of interest in the field of non-thermal processing. The effect of HC on Casein protein's physicochemical and functional properties. HC reduced the crystallization temperature from 230.9 °C in CP1 to 223.2 °C in CP2. The initial viscosity increased significantly to 39,080 Pa s from 26,590 Pa s. HC increased the concentration of amino acids following in-vitro digestion from 145.79 ± 5.7 μg/ml to 194.58 ± 6.3 μg/ml. Trypsin inhibitory reduced up to 44 ± 0.02 % in CP3. The solubility increased from 11.21 ± 0.50 μg/ml to 25.70 ± 1.44 μg/ml in CP2. The water holding capacity of the treated sample increased from 1.73 ± 0.19 g/g in CP1 to 2.52 ± 0.0036 g/g. The oil holding capacity of the treated sample decreased from 0.85 ± 0.02 g/g to 0.67 ± 0.03 g/g.

Comparison between hydrodynamic and ultrasound cavitation on the inactivation of lipoxygenase and physicochemical properties of soy milk

The effects of hydrodynamic cavitation (HC) and ultrasound cavitation (UC) on the lipoxygenase activity and physicochemical properties of soy milk were evaluated. The results revealed that both ultrasound cavitation and hydrodynamic cavitation significantly inactivated the lipoxygenase activity. After the exposure to ultrasound cavitation at 522.5 W/L and 70 °C for 12 min, the lipoxygenase activity was inactivated by 96.47 %. Meanwhile, HC treatment with the cavitation number of 0.0133 for 240 min led to the loss of 79.31 % of lipoxygenase activity. An artificial neural network was used to model and visualize the effects of different parameters after ultrasound cavitation treatment on the inactivation efficiency of soy milk. Turbiscan test results showed that hydrodynamic and ultrasound cavitation decreased the instability index and particle size of soy milk. Moreover, the total free amino acid content was significantly increased after hydrodynamic and ultrasound cavitation treatment. Gas chromatography-mass spectrometry showed that the total content of beany flavor compounds decreased after acoustic cavitation and HC treatment. Acoustic cavitation and HC affected the tertiary and secondary structure of soy milk, which was related to the inactivation of lipoxygenase. We aim to explore a potential and effective way of the application in soy milk processing by comparing the ultrasound equipped with heat treatment and hydrodymic cavitation.

Enhancement of physicochemical stability and reduction in enzyme and microbial activity of apple juice by hydrodynamic cavitation processing

Conventional thermally processed apple juices are nutritionally depleted because the heat sensitivity degrades the bioactive compounds that comprise them. This study proposed a non-thermal technique, hydrodynamic cavitation (HC), to preserve the nutritional content and prevent the loss of bioactive components in apple juice. In addition, the effect of hydrodynamic cavitation on the physicochemical, nutrition, and enzyme inactivation of freshly expressed apple juice has been studied. The design expert software has been used for process optimization, while fuzzy logic was applied for sensory. Hydrodynamic cavitation has been used on freshly extracted apple juice with inlet pressure in the range of (34.47–103.421 kPa) for a treatment time of (0–30 min). The apple juice was treated thermally at 90 °C for 2.5 min to compare the cavitation results. The settling of particles in the cavitation sample was 7%, which was lower than the heat-treated sample (10%) and untreated control sample (39%) and had a noticeable effect on the cloud value and stability of the apple juice. The HC treatment reduces the particle size of fresh apple juice from 8934.09 nm to 1112 nm, resulting in a homogenizing effect, a decrease in viscosity, and improved juice stability. Hydrodynamic cavitation reduced the antioxidant activity from 0.4987 mg GAE mL−1 (control) to 0.3951 mg GAE mL−1 yet retained better activity than the heat-treated apple juice (0.3489 ± 0.34 mg GAE mL−1) with microbial log reduction of 0.9 at 103.42 kPa treated for 30 min. After 15 days of storage at 4 °C, HC-treated juice had higher quality features and nutrient retention than heat-treated apple juice.

Pretreatment of herbal waste using sonication

The effect of hydrodynamic cavitation (HC) and the manner it affects the biodegradability of herbal waste suspended on municipal wastewater subjected to mechanical pre-treatment was examined in this paper. The HC was performed at an optimal inlet pressure equal to 3.5 bar and with the cavitation number of 0.11; the number of recirculation passes through the cavitation zone amounted to 30.5. The BOD5/COD ratio was enhanced by more than 70% between the 5th and 10th minute of the process, indicating the enhanced biodegradability of herbal waste shortly. Fiber component analysis, FT-IR/ATR, TGA and SEM analysis were conducted to check the findings and to demonstrate changes in the chemical and morphological structure of herbal waste. It confirmed that hydrodynamic cavitation visibly influenced the herbal composition and their structural morphology, decreased hemicellulose, cellulose and lignin content, but did not form the by-products affecting the subsequent biological treatment of herbal waste.

Effects of hydrodynamic cavitation and temperature on nanofiltration performance for concentrating ultrafiltered skim milk

The performance of nanofiltration (NF) as influenced by hydrodynamic cavitation (HC) and filtration temperature during the concentration of milk protein concentrate (MPC) was investigated. Pasteurised skim milk was concentrated using ultrafiltration (UF) to prepare UF retentate (MPC80, 20% total solids, TS), which was then further concentrated using NF at 22°C and 50°C with or without HC treatments until permeate flux declined to 0.1 L/m2/h. Results showed that UF retentate can be concentrated to higher TS (up to 31.5%) at higher filtration temperature or by applying HC, with synergistic effect in combination of both treatments, during NF.

Effects of hydrodynamic cavitation at different pH values on the physicochemical properties and aggregation behavior of soybean glycinin

Soybean protein, especially glycinin, easily forms aggregates, limiting its application in some scenarios. In this research, the effects of different hydrodynamic cavitation (HC; 550 W for 0, 10 and 30 min) treatments on soybean glycinin aggregation at different pH values (2, 4, 6, 8 and 10) were investigated. At the five pH values, HC decreased the emulsifying activity index with increasing HC treatment time; however, the effects on the particle size, surface hydrophobicity (H0), solubility and emulsifying stability index (ESI) varied. Notably, HC had more significant effect on the physicochemical structure and functional properties at pH 6 than the other four pH because of different conformational structure, enhancing glycinin's H0 (from 850.95 ± 59.03 to 988.43 ± 64.68), solubility (from 21.85 ± 0.23 to 63.62 ± 1.18 g/100 g), and ESI (from 58.39 ± 7.46 to 127.74 ± 3.43 min). Moreover, HC influenced glycinin aggregation, as demonstrated by the intrinsic fluorescence spectra and circular dichroism results. In conclusion, HC changed the aggregation behavior and improved the functional properties of glycinin, indicating that HC is a promising technique to improve functional properties and provides a reference for the application of soybean protein in the food industry.

Effects of Hydrodynamic Cavitation-Assisted NaOH Pretreatment on Biofuel Production from Cyanobacteria: Promising Approach

Eukaryotic microalgae and prokaryotic cyanobacteria can grow in various water and wastewater types, and both can grow biomass by taking nutrients and converting atmospheric CO2 into useful products. Biofuels obtained by processing this landless grown biomass are defined as “third-generation biofuels”. In this study, the effects of hydrodynamic cavitation (HC)-assisted NaOH pretreatment on methane production from cyanobacteria were investigated. Cyanobacterial biomass was isolated from thermal springs located in the southwest of Turkey (Denizli-Turkey) and identified as Desertifilum tharense. Desertifilum tharense biomass was grown on a laboratory scale, and along with its compositional characteristics, culture-specific parameters were determined. HC-assisted NaOH pretreatment was applied to evaluate optimum process conditions for enhancing methane production from D. tharense. In the experimental design, process parameters of cavitation number (Cv: 0.3-0.7), NaOH concentration (0–4%), solid content (1.5%), reaction time (4h), and reaction temperature (30°C) were combined to reveal the parameter-specific impact of HC pretreatment. The effect of the HC-assisted NaOH pretreatment was further investigated with molecular-bond and surface structure characterization. Along with the energy equivalent of obtained biofuel, energy requirements for cultivation, harvesting, pretreatment, and anaerobic digestion (AD) were calculated to determine the process’s overall energy efficiency. Kinetic parameters of raw and pretreated D. tharense were determined by first-order, cone, modified Gompertz, and reaction curve models. The results revealed that by the application of pretreatment, a 2-35.3% soluble COD increase was achieved, whereas methane production was increased from 241.5 to 290.6 mLCH4 gVS−1. Application of HC with a low Cv of 0.3 boosted methane production up to 20.3% compared to the raw D. tharense.

Effect of hydrodynamic cavitation on flocs structure in sewage sludge to increase stabilization for efficient and safe reuse in agriculture

Sewage sludge is the by-product of wastewater treatment processes. Its reuse is central to a circular economy approach and offers a sustainable alternative to its disposal. Treated sludge contains a wide range of nutrients (mainly nitrogen, phosphorus, and potassium), which favor its sustainable employment for agricultural purposes (land-spreading, compost production) and environmental requalification interventions (forestry, silviculture, land reclamation and revegetation). However, if not properly treated, sewage sludge can contain various contaminants such as heavy metals, organic pollutants, pathogens, and other emerging contaminants, which pose a threat for crops production and human health. Hydrodynamic cavitation (HC) is an eco-friendly and cost-efficient pretreatment that can enhance sewage sludge stabilization in both anaerobic and aerobic digestion units, thereby making safe its management and disposal. In this study, HC was used for the gradual disintegration of activated sludge (reaching a maximum disintegration degree (DDPCOD) of 19.2% after 8 h of treatment), and the solubilization of the dissolved organic matter (increasing the Soluble Chemical Oxygen Demand (SCOD) from 244 to 4,578 mg L−1 after 8 h of treatment). Then, both dynamic light scattering analysis and stereoscopic microscope observations proved that HC can also lead to a size reduction of sludge suspended particles. In addition to evaluate the HC treatment efficiency, in this work was also provided a brief discussion on the possible procedures to be followed for the safe and efficient sewage sludge disposal on land after it has been HC-treated.

Increasing the energy efficiency and environmental safety of the operation of smallvolume furnaces by adding a water-fuel mixture and organic components

Industrialisation is trending manufacturing revolution vector, an urgent task is to increase the energy efficiency and environmental safety of small-volume furnaces processes, which are widely applied in the agricultural industry, asphalt concrete plants, etc. In many countries, there are practically no working coal mines or open-pit mines left. However, in a number of regions, coal waste remained in the form of coal dust, ash or in the form of sludge. Utilization of coal dust by preparation of coal-water fuel (CWF) with subsequent combustion of the mixture is currently being applied as the most suitable method. The article discusses improvement of the technology for the preparation of coal-water fuel by applying the effects of hydrodynamic cavitation and adding waste from the livestock complex.

Novel, non-thermal hydrodynamic cavitation of orange juice: Effects on physical properties and stability of bioactive compounds

Effect of hydrodynamic cavitation (HC) at pressure 3–15 bar and treatment time5–25 min on physical and chemical qualities of orange juice was investigated. Processing parameters were optimized on the basis of retention of vitamin C and antioxidant activity; inactivation of pectin methyl esterases (PME) and peroxidase (POD) enzyme and stability of pH, °Brix, viscosity, titratable acidity and total color difference. HC of orange juice at 5 bar 15 min and 13 bar 10 min resulted into maximal overall desirability at 0.52 and 0.40 respectively. No significant change in °Brix, pH, titratable acidity for fresh and cavitated orange juice was observed. Only 21% and 13% of reduction in PME and POD respectively was recorded. A 94% and 91% of antioxidant activity and vitamin C retention was noted in both optimized samples. This study demonstrated that HC can produce orange juice more economically with better physical properties and nutritional value. Industrial relevanceThe demand for more natural, preservative free with highest nutritional bioactive containing juices has created a need of non-thermal processing. Hydrodynamic cavitation (HC) processing is novel, emerging and under explored technology for fruit juices. HC due to the formation of cavities and shock waves causes enzyme and microbial inactivation at low temperature while retaining natural bioactives with fresh-like organoleptic characteristics. It is believed worldwide that non thermal technologies like HC will be among the most cost effective, scalable and impactful liquid food processing technologies in the coming decades especially for commercial products.

Effects of hydrodynamic cavitation, low-level thermal and low-level alkaline pre-treatments on sludge solubilisation.

WAS is a polluting and hazardous waste generated in WWTPs that must be treated to prevent pollution and human health risks. Anaerobic digestion is the most used process for sludge stabilization. However, it must be improved in terms of both speed and extend of degradation. With the purpose of reducing the energy and chemical consumption linked to sludge treatment, in this study, different anaerobic digestion pre-treatments such as low-level mechanical (hydrodynamic cavitation, 2 bar), low-level thermal (50 °C) and low-level alkaline (NaOH, KOH and Ca(OH)2, pH 10) methods, and a combination thereof, were tested as strategies to improve sludge solubilisation. When the pre-treatments were used alone, the alkaline pre-treatment showed the highest sludge solubilisation. Among the alkaline reagents tested, NaOH and KOH led to higher DDPCOD (41.6 and 39.4%), while only 8.4% was achieved by using Ca(OH)2. However, the low-level hydrodynamic cavitation assisted thermo-alkaline pre-treatment was the most efficient in terms of both sludge solubilisation (DDPCOD = 53.0%) and energy efficiency (EE = 64.5 mgΔSCOD kJ-1). The synergetic effects of the combined pre-treatment were also confirmed by the highest release of EPS. Furthermore, cytometric analyses showed that the main mechanism involved in sludge solubilisation for the investigated pre-treatments was flocs disintegration rather than cell lysis.

Effect of hydrodynamic cavitation on the absorption processes occurring in the production of nitric acid

Effect of hydrodynamic cavitation on the absorption processes occurring in the production of nitric acid

The effect of hydrodynamic cavitation on performance of the alkaline aluminosilicate coatings for metal structures

Load-bearing metal structures working in atmospheric conditions are exposed to corrosion. Known-in-the art paint-and-lacquer protective coatings can provide protection of metal for rather short period of time (5…10 years). These structures can be effectively protected by more advanced coatings of new generation, namely: alkaline aluminosilicate binder-based coatings of barrier type. These binders differ from the known-in-the-art binding materials by formation in their hydration products of zeolite-like minerals and feldspathoids. The paper discusses principles laid down in formulating the binder composition in the (хК, уNa)2OAl2O3nSiO2mH2O system, target synthesis of hydration products of the binder matrix under influence of dynamic of the binder matrix in cavitation, optimal parameter order to synthesis of cavitation treatment aimed at nanostructuring of zeolite-like and hydromica phases after solidification. These coatings exhibit high corrosion resistance, high adhesion to metal substrate and durability results of restoration works that had been carried out in December 2010 of the Big Bell Tower of the Kiev Petchersk Lavra in order to protect corroded metal surfaces by applying the aluminosilicate binder-based coatings, the major constituent (binder) of which was represented by (0.72Na2O+0.28K2O)1.5Al2O3(4.56)SiO217.5H2O are discussed in details. In 2016, after 6 years of service in high humidity conditions and other aggressive exposures, the coated metal structures were examined and no sign of corrosion of metal substrate and damage of the applied coating was found.

Effect of hydrodynamic cavitation in the tissue erosion by pulsed high-intensity focused ultrasound (pHIFU)

High-intensity focused ultrasound (HIFU) is emerging as an effective therapeutic modality in clinics. Besides the thermal ablation, tissue disintegration is also possible because of the interaction between the distorted HIFU bursts and either bubble cloud or boiling bubble. Hydrodynamic cavitation is another type of cavitation and has been employed widely in industry, but its role in mechanical erosion to tissue is not clearly known. In this study, the bubble dynamics immediately after the termination of HIFU exposure in the transparent gel phantom was captured by high-speed photography, from which the bubble displacement towards the transducer and the changes of bubble size was quantitatively determined. The characteristics of hydrodynamic cavitation due to the release of the acoustic radiation force and relaxation of compressed surrounding medium were found to associate with the number of pulses delivered and HIFU parameters (i.e. pulse duration and pulse repetition frequency). Because of the initial big bubble (~1 mm), large bubble expansion (up to 1.76 folds), and quick bubble motion (up to ~1 m s−1) hydrodynamic cavitation is significant after HIFU exposure and may lead to mechanical erosion. The shielding effect of residual tiny bubbles would reduce the acoustic energy delivered to the pre-existing bubble at the focus and, subsequently, the hydrodynamic cavitation effect. Tadpole shape of mechanical erosion in ex vivo porcine kidney samples was similar to the contour of bubble dynamics in the gel. Liquefied tissue was observed to emit towards the transducer through the punctured tissue after HIFU exposure in the sonography. In summary, the release of HIFU exposure-induced hydrodynamic cavitation produces significant bubble expansion and motion, which may be another important mechanism of tissue erosion. Understanding its mechanism and optimizing the outcome would broaden and enhance HIFU applications.

Visualization of microscale cavitating flow regimes via particle shadow sizing imaging and vision based estimation of the cone angle

Recent studies show the destructive effect of the energy released from the collapse of cavitation bubbles, which are generated in micro domains, on the targeted surfaces. The cavitation phenomenon occurs at low local pressures within flow restrictive elements and strongly affects fluid flow regimes inside microchannels which results in spray formation. Extended cavitation bubbles toward the outlet of the microchannel, droplet evolution, and spray breakup are among crucial mechanisms to be considered in spray structure. In this study, various spray structures under the effect of hydrodynamic cavitation were recorded using a high speed visualization system. Acquired images were analyzed and characterized using several image processing algorithms. In this regard, the fluid flow with ascending upstream pressures from 10 to 120bar were passed through a microchannel with an inner diameter of 0.152mm. The spray at the outlet of the microchannel was analyzed for these pressures in four different segments. Particle Shadow Sizing (PSS) imaging and several image processing techniques such as contrast stretching, thresholding and morphological operations were employed to identify the flow regimes in the separated segments. In addition, a vision based estimation technique that utilizes a Kalman filter was developed to estimate cone angle of the spray. Furthermore, classification of fluid flow regimes and morphological characteristics of the spray structure were outlined based on the cavitation number.