Venturi Injector Research Articles

Structural optimization of the low-pressure Venturi injector with double suction ports based on computational fluid dynamics and orthogonal test

Structural optimization of the low-pressure Venturi injector with double suction ports based on computational fluid dynamics and orthogonal test

Farklı Fertigasyon Teknikleri ve Su Kısıntısı Koşullarında Domates Bitkisinin Su Verim İlişkilerinin Belirlenmesi

Success of the fertigation techniques on drip irrigation which water and fertilizer are used together depends on fertilizer concentration, distrubition and transmission type to crop in time. Especially, consideration of the adverse effects of the climate changes on water supplies, fertilization with deficit irrigation regimes is more important for plant growth. In this study effects of F1 injection pump, F2 venturi injector and F3 pressure diversity fertigation techniques with I100, I70 and I50 irrigation treatments on tomato was determined. Results of the 2014 experiment year, the highest yield was obtained as 4875 kg da-1 in F1 injection pump and I100 full irrigation treatments. The highest seasonal evapotranspiration was obtained as 584.7 mm in F2 venturi injector and I100 full irrigation treatments while the highest irrigation amount was 397.7 mm on I100 full irrigation treatments.

Simulation and Optimization of Venturi Injector by Machine Learning Algorithms

AbstractThis paper discusses the problem of low injection rates from Venturi injectors. The optimal combination of key structural parameters for Venturi injectors was investigated using a simulatio...

Numerical and Experimental Study on the Internal Flow of the Venturi Injector

To study the appropriate numerical simulation methods for venturi injectors, including the investigation of the hydraulic performance, mixing process, and the flowing law of the two internal fluids, simulations and experiments were conducted in this study. In the simulations part, the cavitation model based on the standard k–ε turbulence and mixture models was added, after convergence of the calculations. The results revealed that the cavitation model has good agreement with the experiment. However, huge deviations occurred between the experimental results and the ones from the calculation when not considering the cavitation model after cavitation. Thus, it is inferred that the cavitation model can exactly predict the hydraulic performance of a venturi injector. In addition, the cavitation is a crucial factor affecting the hydraulic performance of a venturi injector. The cavitation can ensure the stability of the fertilizer absorption of the venturi injector and can realize the precise control of fertilization by the venturi injector, although it affects the flow stability and causes energy loss. Moreover, this study found that the mixing chamber and throat are the main areas of energy loss. Furthermore, we observed that the internal flow of the venturi injector results in the majority of mixing taking place at the diffusion and outlet sections.

Applications of computational fluid dynamics in irrigation engineering

Computational fluid dynamics (CFD) techniques have become an important tool for investigating and predicting flow behavior in many industrial and engineering processes. In the last two decades, CFD has been used for the study, design, and improvement of irrigation equipment. Numerical simulations can be used to predict fluid flow, heat transfer, and chemical reactions within complex systems. The objective of this review is to provide an overview of the uses of CFD in irrigation engineering applications. The paper is organized into two main sections: fundamentals of CFD and irrigation engineering applications. The first section presents the main methods used in numerical simulations, basic equations to predict fluid flow parameters, meshing concerns, and convergence criteria. In the second section, we present applications related to friction and local head losses in pipes, liquid and solid-liquid flow simulation in drippers, chemical scaling, filters, sprinklers, direct-acting pressure-regulating valves, and Venturi injectors. The briefly described applications indicated that CFD modeling can be an accurate, quick, and feasible method for the investigation of flow parameters in irrigation pipes, fittings, emitters, and accessories. The CFD simulations can be useful for designing new products as well as for improving and optimizing existing products. Computational fluid dynamics uses in irrigation engineering must be encouraged, particularly for innovation purposes resulting from the cooperation between academia and irrigation companies.

Evaluation of acetic acid and ethanol concentration in a rice vinegar internal venturi injector bioreactor using Fourier transform near infrared spectroscopy

In the process of fermenting rice vinegar, the concentration of acetic acid and ethanol concentration must be measured for monitoring of the total concentration. Near infrared spectroscopy has been used to rapidly monitor the concentration of acetic acid and ethanol concentration daily during 10 cycles of the fermentation process. The model was developed using partial least squares regression. For predicting concentration of acetic acid with near infrared spectroscopy, the coefficient of determination ( R2), root mean square error of calibration, root mean square error of cross validation, ratio of standard error of validation to standard deviation, and bias was 0.96, 2.30 g L−1, 2.44 g L−1, 1.11 g L−1, and 5.56, respectively. For ethanol concentration, the value of R2, root mean square error of calibration, root mean square error of cross validation, bias and ratio of prediction to deviation were predicted to be 0.94, 3.15 g L−1, 2.73 g L−1, −0.40 g L−1, and 4.04, respectively. However, both models provided fair performance when tested with an external set of samples, indicating that the models could be applied for rough screening.

Characterization of venturi injector using dimensional analysis

ABSTRACT Venturi injectors are commonly employed for fertigation purposes in agriculture, in which they draw fertilizer from a tank into the irrigation pipeline. The knowledge of the amount of liquid injected by this device is used to ensure an adequate fertigation operation and management. The objectives of this research were (1) to carry out functional tests of Venturi injectors following requirements stated by ISO 15873; and (2) to model the injection rate using dimensional analysis by the Buckingham Pi theorem. Four models of Venturi injectors were submitted to functional tests using clean water as motive and injected fluid. A general model for predicting injection flow rate was proposed and validated. In this model, the injection flow rate depends on the fluid properties, operating hydraulic conditions and geometrical characteristics of the Venturi injector. Another model for estimating motive flow rate as a function of inlet pressure and differential pressure was adjusted and validated for each size of Venturi injector. Finally, an example of an application was presented. The Venturi injector size was selected to fulfill the requirements of the application and the operating conditions were estimated using the proposed models.

Treatment of Tofu Industry’s Wastewater Using Combination of Ozonation and Hydrodynamic Cavitations Method with Venturi Injector

Indonesia is one of the country with the biggest population of tofu industries in the world. Tofu wastewater can harm the environment and alter the physical and chemical properties of water in river bodies, which is dangerous for human and living organism within the river. So it needs to be treated before disposed into the environment. The purpose of this research is to evaluate the performance of ozonation [O], hydrodynamic cavitations [HC], and combination of both [HC/O] in treating tofu wastewater. The variations of circulation flow rate are 2, 3, and 4 LPM and dosage of ozone is single and series ozonator. [HC/O] method (4 LPM flowrate and 129 mg/h dosage of ozone) produces the best performance, with degradation of 943 mg/L COD and 293 mg/L TSS in 180 minutes. This result is much better than the 4 LPM variant of [HC] method and series variant of [O] method separately, which are only capable of degrading 485 mg/L COD-288 mg/L TSS and 136 mg/L COD-233 mg/L TSS in 180 minutes accordingly.

Disinfection of Escherichia coli Bacteria Using Combination of Ozonation and Hydrodynamic Cavitation Method with Venturi Injector

This study brings out a disinfection process of bacteria Escherichia coli using a combination of ozonation and hydrodynamic cavitation method. Cavitation was generated using venturi injector, and three commercial Ozonator was used for generated ozone. Various configuration method was arranged to evaluate the performance of each kind method as well as a combination of them on the disinfection process. Effect of various flow rate (3, 5, and 7 LPM) and dosage of ozone (64.83, 108.18, and 135.04 mg/h) was investigated. Combination of ozonation and hydrodynamic cavitation (7 LPM and 135.04 mg/h dosage of ozone) showed the best performance with initial concentration is 1.49 x 10 5 CFU/mL; all bacteria were disinfected for 45 min. The results are better than the single hydrodynamic cavitation method (7 LPM) which had 21% remaining of bacteria, and all bacteria were disinfected on a single ozonation method (135.04 mg/h dosage of ozone) for 60 min.

Calcification in Caribbean reef-building corals at high pCO2 levels in a recirculating ocean acidification exposure system

Projected increases in ocean pCO2 levels are anticipated to affect calcifying organisms more rapidly and to a greater extent than other marine organisms. The effects of ocean acidification (OA) have been documented in numerous species of corals in laboratory studies, largely tested using flow-through exposure systems. We developed a recirculating ocean acidification exposure system that allows precise pCO2 control using a combination of off-gassing measures including aeration, water retention devices, venturi injectors, and CO2 scrubbing. We evaluated the recirculating system performance in off-gassing effectiveness and maintenance of target pCO2 levels over an 84-day experiment. The system was used to identify changes in calcification and tissue growth in response to elevated pCO2 (1000μatm) in three reef-building corals of the Caribbean: Pseudodiploria clivosa, Montastraea cavernosa, and Orbicella faveolata. All three species displayed an overall increase in net calcification over the 84-day exposure period regardless of pCO2 level (control +0.28–1.12g, elevated pCO2 +0.18–1.16g), and the system was effective at both off-gassing acidified water to ambient pCO2 levels, and maintaining target elevated pCO2 levels over the 3-month experiment.

Evaluation of Drip Fertigation Uniformity Affected by Injector Type, Pressure Difference and Lateral Layout

AbstractThe effects of three injector types (differential pressure tank, Venturi injector and water‐driven piston proportional pump), three pressure differences (0.10, 0.15 and 0.20 MPa) and two lateral layouts (longitudinal and transversal) on drip fertigation uniformity were comprehensively evaluated through field experiments. No statistically significant differences in water uniformity were found between injector types or pressure differences, while the influence of lateral layouts on water uniformity was significant (α = 0.05). All affecting factors showed an extremely significant influence on fertilizer uniformity (α = 0.01). Water uniformity was better than fertilizer uniformity, both of which generally decreased with increasing pressure differences. The differential pressure tank produced a lower water and fertilizer uniformity than the Venturi injector and proportional pump. The longitudinal lateral layout produced lower fertigation uniformity than the transversal lateral layout. To ensure both high water and fertilizer uniformity in fertigation systems, a Venturi injector and a proportional pump with relatively constant fertilizer concentration are recommended. When a differential pressure tank is used, the differential pressure should be minimized to mitigate the decrease in fertilizer concentration. The differential pressure tank can give high fertigation uniformity (≥ 90%) comparable to the Venturi injector and proportional pump if the transversal lateral layout is further applied. The research provides scientific guidance for the design and operational management of drip fertigation systems in greenhouse vegetables or field crops. Copyright © 2017 John Wiley & Sons, Ltd.

Micro-Venturi injector: design, experimental and simulative examination

This paper reports the first factorial design of a micro Venturi injector completed by a simulative investigation of the device. For the first time, a comprehensive correlation between the point of the maximum vacuum pressure generated by the Venturi nozzle and the variation of the inlet pressure is shown. The device reported in this contribution enables a new solution for robust low-pressure generation in parallel fluidic channels.

Geometry and head loss in Venturi injectors through computational fluid dynamics

ABSTRACT To determine the influence of geometry on the hydrodynamic behavior of Venturi injectors, using computational fluid dynamics techniques, we studied, at the Universitat Politècnica de València, Valencia, Spain, the geometric parameters that exert the most influence on head losses: the relationship between throat diameter and nozzle (β), nozzle angle (α1) and diffuser angle (α2). In addition, three throat morphologies (B1: nozzle-throat and throat-diffuser with a sharp edge; B2: nozzle-diffuser with a zero-length, sharp-edge throat; B3: nozzle-throat and throat-diffuser with rounded edge). We analyzed their influence on the velocity distribution and differential pressure between inlet and throat (DP/γ), throat and outlet (Δhv/γ), and outlet and throat ((P3-P2)/γ). The development of the velocity profile from the throat is slower the greater β is and the lower α2 is. DP/γ decreases with β, increases with α1 and varies little with α2. Δhv/γ decreases with β and increases with α1 and α2. (P3-P2)/γ decreases with β and increases with α1 and α2. Geometry B3 decreases the losses and delays the onset of cavitation. Thus, the lower β and the higher α2, the greater the losses; however, the influence of α1 is less clear. The rounded edges produce lower head losses.

Investigation of the cavitation fluctuation characteristics in a Venturi injector

The suction flow rate in a Venturi injector increases to a maximum and appears to be unstable when critical cavitation occurs. This study analyzes changes in the cavitation length in high-speed videos of a Venturi injector with critical cavitation to find periodic fluctuations in the cavitation cloud. Pressure fluctuation measurements show a dominant low frequency fluctuation that is almost as large as the oscillation frequency seen visually for the same conditions. The variation of the cavitation numbers and the measured transient outlet pressure show that critical cavitation occurs in the Venturi injector when the peak-to-peak pressure difference is greater than a critical value. Moreover, when the cavitation numbers become very small in the cavitation areas, the peak-to-peak pressures begin to decrease. The relationship between the suction performance and the outlet pressure fluctuations has a significant inflection point which can be used to determine proper working conditions. These experimental statistics provide a pressure range based on the inlet and outlet pressures for which the improvement of suction performance will not substantially change the outlet pressure fluctuations. Both the high-speed photography and the pressure measurement show the periodic oscillations of the cavitation cloud in a Venturi injector and can be used to detect the occurrence of critical cavitation.

Impact of high initial concentrations of acetic acid and ethanol on acetification rate in an internal Venturi injector bioreactor.

To evaluate the comparative impact of high initial concentrations of acetic acid (AAi ) and of ethanol (ETi ) on acetification rate (ETA). Acetic acid bacteria (AAB) were cultivated in a 100-l internal Venturi injector bioreactor. To quantify the oxygen availability, the 1.0 l min(-1) air inflow rate for the start-up phase (25 l) while 3·0 l min(-1) for the operational phase (75 l) achieved a high oxygen transfer coefficient (kL a). Changes in cell wall by TEM images and the remained ADH and ALDH activities confirmed the high acid tolerance ability of AAB. While ETAs using high AAi at 65 g l(-1) could be processed of 9.57 ± 0.19 g l(-1) day(-1) , which is just higher than 9.12 ± 0.12 g l(-1) day(-1) using high ETi at 55 g l(-1) . The average biotransformation yields were at 96.3 ± 0.1% and 94.4 ± 0.1% for high AAi and ETi , respectively. Results confirm that high oxygenation was generated in the bioreactor. Both high AAi and ETi were important in increasing ETA under stress 100 g l(-1) total concentration. High acid-tolerant AAB contains the high ADH and ALDH activities causing higher ETAs in HIA process. It is a competitive commercialized acetification process.

Design and installation alternatives of Venturi injectors in drip irrigation

En la Universitat Politècnica de València, Valencia, España (39° 29’ N; 0° 23′ W; 20 m), ha sido estudiado el funcionamiento de cuatro prototipos de inyector Venturi y tres formas de instalación distintas. El funcionamiento se ha analizado bajo diversos parámetros, como pérdidas de carga, relación de caudales y rendimiento. Las formas de instalación analizadas han sido: sin inyección y con inyección y presiones negativas o positivas en la garganta. Las presiones se establecieron entre 10 y 40 m.c.a. A partir de los datos experimentales han sido procesados utilizando técnicas de regresión múltiple y análisis de la varianza. Con ellas, fue posible, a través de la integración de geometrías en función de los diámetros, caudales y presiones, obtener expresiones para prever la pérdida de carga o el caudal inyectado. Se pone de manifiesto que la relación de caudales y el rendimiento son mayores cuanto mayor es el diámetro de la aspiración y empeoran al reducirse el diámetro de la garganta, siendo estas las dimensiones que más condicionan la inyección. También, puede afirmarse que la pérdida de carga, para un mismo caudal inyectado, es inferior si la operación se realiza con presiones positivas que con presiones negativas. La relación de caudales o el rendimiento también proporcionan valores más elevados bajo esta forma de instalación propuesta.

Adjustable-Rate Fertigation System

<abstract> <bold><sc>Abstract. </sc></bold>Site-specific fertigation can limit fertilizer waste and loss to the environment, but is not easily implemented when there are many small hydrozones, each demanding a unique rate of fertilizer application. With a simple and inexpensive fertilizer injection system, a separate injector could be installed at each zone to provide a unique fertilizer delivery rate, even when those zones are in simultaneous operation. Integration with a wireless control network would allow automated adjustment of the fertilizer delivery rate for each hydrozone and aid installation in existing facilities. A variable-rate injector was developed using a simple venturi injector, solenoid valve, electrical conductivity (EC) sensor, and small computer board (controller). EC was related to fertilizer concentration expressed as parts-per-million (ppm) nitrogen (N). Fertilizer injection rate was controlled by opening and closing a solenoid valve connected to the suction line of the venturi injector. The rate was adjusted by changing the valve duty cycle (percentage of time that the valve was open). For initial testing with a 2000 ppm N stock solution, the duty cycle was manually adjusted from 0 to 100% to deliver an applied fertilizer concentration of 0 to 200 ppm N at an injection ratio of about 1:10. For closed-loop control, the controller was programmed to monitor EC and automatically increase or decrease the valve duty cycle in order to achieve the target fertilizer concentration. The root mean square percentage error for the closed-loop control injection system was 4.8% in laboratory tests over a target range of 0 to 200 ppm N. A mobile injector station was assembled and integrated with a wireless sensor and control network in order to test adjustable-rate fertigation in container nurseries. Field trials to deliver specified nitrogen concentrations to several different nursery beds gave a root mean square percentage error of 2.2% over a target range of 50 to 150 ppm N. The fertilizer concentrations matched that specified by the user, indicating that the system did a good job of adjusting the duty cycle to meet the target rate, and the irrigation and fertilizer injection durations were correct. Furthermore, the wireless network performed well and exhibited acceptable range.

Diseño y predicción del funcionamiento de inyectores Venturi en riego localizado

En la Universitat Politècnica de València, Valencia, España, se ha estudiado el diseño y funcionamiento de cuatro prototipos del inyector Venturi con técnicas de Dinámica de Fluidos Computacional (CFD), comparándo las con ensayos en laboratorio. Para cada prototipo, las geometrías definidas y analizadas han permitido simular el funcionamiento sin (G1) y con inyección (G2) para quimigación. En el caso G1, se presentan los gráficos del perfil de presiones en el eje del inyector para diversas velocidades, así como la distribución del campo de presiones y de la evolución de las diferencias de presión y pérdidas de carga frente al caudal principal. Para comparar los resultados obtenidos con CFD frente al resultado experimental, se calculó el error relativo. En el caso G2, se obtuvo la representación gráfica del el caudal de inyección frente al caudal principal. Las técnicas CFD exigen un buen ajuste del modelo para dar un resultado aceptable. Son interesantes para comparar geometrías, analizar sus variantes, realizar prediseños y aproximar ordenes de magnitud, pero es recomendable su ensayo en laboratorio para validar los resultados.

Practical realisation of ozone clearing after disperse dyeing of polyester

In this study, a novel system utilising ozone in jet dyeing machines is introduced, and the results of ozone‐clearing treatments of disperse dyed polyester on the prototype modified machine are reported. A Venturi injector was mounted on the liquor circulation pipe of the jet dyeing machine to feed ozone gas into the machine. Ozone was generated via an ozone generator by feeding conditioned air into the generator. The ozone gas entering the pipe partly dissolved in the treatment liquor; the dissolved portion and the gaseous ozone interacted via the fabric in the pipe, especially in the nozzle and also at the bottom of the autoclave (machine body). Disperse dyed polyester fabrics of textile‐company mass production were ozone cleared in this prototype. Ozone clearing was achieved in cold water (room temperature), and no other chemicals were used. The colour of the samples, wet fastness properties, and the chemical oxygen demand of the effluent were investigated, and costs were compared with those of conventional reduction clearing of ozone. Results were outstanding: an 83% cost reduction, 67% timesaving, and an 88% COD reduction were achieved.

Detection of Cavitation in a Venturi Injector With a Combined Method of Strain Gauges and Numerical Simulation

The fertilizer suction capability of a Venturi injector is dependent on the vacuum pressure in the throat portion. As the vacuum level drops below the saturation vapor pressure, the pressure decreases to a particular value corresponding to the maximum pressure difference (Δpmax) between inlet and outlet pressures, and critical cavitation is likely to occur, leading to an unstable suction flow rate and low fertilization uniformity. A new method of using strain gauges to detect cavitation in Venturi injectors was explored experimentally and verified numerically under various operating conditions. The standard deviation (SD) of the measured strain values and the simulated values of the vapor-phase volume fraction (Vf) were used to evaluate the influence of cavitation. The results showed that both the rate of increase (ηm) of the average SD and the average growth rate (AGR) of the simulated cavitation length reach relatively large values at the maximum pressure difference (Δpmax), where the measured suction flow rate simultaneously reaches a maximum. In addition, SD and Vf shared similar variation trends at pressure differences larger than the corresponding Δpmax under various conditions. This new cavitation detection method has been proved to be feasible and reliable. It helps to determine accurately the value of Δpmax at different inlet pressures and to ensure that the Venturi injector runs in a safe operating-pressure range.