Injection Of Type Research Articles

ASYMMETRIC BREAKUP OF ANNULAR LIQUID SHEETS IN LIQUID-CENTERED SWIRL COAXIAL INJECTORS

Cryogenic rocket engines use swirl coaxial injectors due to their consistent spray characteristics over a wide range of operating conditions. Axisymmetric liquid sheets are formed in liquid-centred swirl coaxial injectors of cryogenic engines at their nominal operating conditions. The azimuthal uniformity of the spray formed in this type of injector depends on the swirler configuration and geometry of the flow passages. The liquid sheet breaks into ligaments and then into multitude of droplets due to aerodynamic interaction of the liquid sheet with the surrounding gas. The inner and outer swirl injectors are cold flow characterized using water and nitrogen gas, respectively. Asymmetric breakup of conical liquid sheets was investigated at different gas Weber numbers using flow visualization techniques. Azimuthal uniformity of the spray was determined from the measurements of mechanical patternator. It is of paramount importance to determine the effect of gas swirl on spray uniformity of liquid-centered swirl coaxial injector for different gas-to-liquid mass ratios. It was observed that swirl in the co-flowing gas reduces the inherent asymmetry of the liquid sheet.

Impact of Patient Volume on Iodinated Contrast Material Waste with Multidose Contrast Injectors.

Multidose iodinated contrast media (ICM) injectors have shown promise in reducing ICM waste. This study aims to evaluate the impact of patient volume on ICM waste reduction in multidose injectors. CT studies performed over one-year period with a multidose injector at our emergency CT unit. We recorded the ICM volume, time, and date for each injection and calculated total annual ICM use, accounting for the 500mL ICM containers' 8-hour window usage limit. We then calculated the ICM waste for the same patient cohort assuming single-dose vials used with single-dose injectors were used instead, without the 8-hour window for usage. To assess the impact of patient volume, we evaluated six subgroups based on daily injected patient counts: Group 1 (<10 patients/day), Group 2 (10-19 patients/day), Group 3 (20-29 patients/day), Group 4 (30-39 patients/day), Group 5 (40-49 patients/day), Group 6 (≥50 patients/day). Annual and mean per patient ICM waste was calculated for both injector types and compared among all subgroups. In total, across 12,290 scans, multidose injectors reduced annual ICM waste by 86.1% compared to single-use injectors. Annual ICM waste was zero on days with 50 or more patients and was minimal (253mL) for days with 40-49 patients. A significant negative correlation between patient volume and ICM waste was observed (r=-0.365, p<0.0001). Mean ICM waste per patient was 2.5 times higher in Group 1 and 71.4% higher in Group 2 with multidose injector compared to single-dose injector. Conversely, in groups with at least 20 patients per day, mean ICM waste per patient was lower with multidose injectors compared to single-dose injectors. Mean ICM waste per patient was reduced by 53.9% in Group 3, 88.9% in Group 4 and 100% in Group 6. High patient throughput centers with over 40 patients per day can nearly eliminate ICM waste with multidose injectors. However, using multidose injectors in centers with lower patient volumes (<20 patients per day) may lead to increased ICM waste compared to single-dose injectors, underscoring the importance of aligning injector choice with patient volume to optimize resource utilization and minimize waste.

Influence of propellant injection directionality on the performance of an argon Hall thruster

The performance characteristics of an argon propellant Hall thruster with two types of propellant injectors, the axial and swirl injectors, were investigated. In the swirl injector, the propellant is injected in the tangential direction. At a discharge voltage of 150 V, the swirl injector achieved a higher propellant utilization efficiency (30.3%) and anode efficiency (8.8%) compared to the axial injector (26.7% and 7%, respectively). A numerical simulation quantitatively explained the reason for these differences, which shows an increase in the neutral particle density of 32.6% near the injection region and 7.8% at the exit of the hollow anode with the swirl injector. Neutral particle accommodation on the anode wall was found to be the predominant mechanism, which reduces the injection effect.

Development of a PXIe-based data acquisition and control system for hydrogen pellet injection system

A data acquisition and control (DAC) system has been developed for the solid hydrogen pellet injection system. This injector is a gas gun type injector, where solid hydrogen pellet ice is formed using a closed cycle cryocooler, and high-pressure helium gas or a pneumatic punch is used to dislodge the pellet. The DAC system is based on National Instrument's embedded controller NI PXIe-8133, along with associated I/O DAC cards and the LabVIEW application. A graphical user interface (GUI) developed using LabVIEW software allows users to remotely control the pellet formation and injection process. The data is stored locally on a desktop computer or in cloud storage for further analysis. The images of the injected pellet were obtained by using a Phantom V-1210 high-speed camera at 100-Killo FPS, which reveals the size and speed of the pellet. The developed DAC system provides the flexibility needed to operate the injector remotely during the plasma discharge in a tokamak environment. The injector setup system has been successfully tested in a test bench operation, and it will be integrated with the ADITYA-U tokamak.

Effect of incoming flow conditions on air lubrication regimes

Different air phase regimes are formed by controlled air injection in a spatially developing flat plate turbulent boundary layer (TBL). The air is introduced via a slot type injector without the use of a backward-facing step or cavitator upstream of the air injection position. The effect of different incoming liquid flow characteristics on the different regimes is investigated by varying both the liquid freestream velocity and the incoming TBL thickness. The latter is realized through changing the position of the air injection along the length of the water tunnel facility. That resulted in a downstream distance based Reynolds number from 1 to 5 million. Three different air phase regimes are identified under different air flow rates and freestream velocities: the bubbly regime, the transitional, and the air layer regime. The morphological differences of each one are described and quantitative analysis is performed based on the non-wetted area in each condition. The incoming TBL as well as the flow around the air layer are measured with planar particle image velocimetry. The latter enabled the determination of the air layer thickness. In addition, the ratio of the air layer to the incoming boundary layer thickness tair/δ is also calculated (≈ 0.04 – 0.5). This is a significant dimensionless parameter for scaling, which indicates the extent to which the air layer is embedded within the incoming TBL. Depending on the incoming flow conditions, a two or three branch air layer is formed. The length of the air layer is found to increase with increasing liquid freestream velocities. A good agreement between the air layer length and a half gravity wave predicted by the dispersion relation is found. An increase of the air layer length is observed with a decreasing incoming TBL thickness. This is attributed to a decrease in the local mean velocity at the air–water interface due to the TBL growth. Finally, increasing the incoming TBL thickness delays the onset of the air layer regime.

Analisis Jumlah Lubang Injektor dan Nilai Oktan Terhadap Kinerja Motor Bensin

The rapid development of the automotive sector in electronic systems is accompanied by an increase in injector types that have different numbers of holes, especially on motorbikes. It is hoped that the different number of holes in the injector will have certain advantages which are expected to improve its performance. This research aims to determine the effect of using variations in the number of holes in the injector and the octane value of the fuel on petrol motor power. The research method uses experiments with descriptive analysis. The independent variable is the number of holes in the injector, 4, 6, and 8 and the octane value of the fuel is 90 and 92. In the power testing process using engine speed from 1000 rpm to 9000 rpm and the bound variable is the power. The results of this research show that there is a significant influence with the greatest power on the type of injector with 4 holes and fuel with an octane value (RON) of 92, namely 6.072 [kW] at an engine speed of 6500 [rpm]. When using fuel with an octane rating (RON) of 90, the greatest power in the injector type with 6 holes is 5,451 [kW] at an engine speed of 7000 [rpm]. In general, all types of injectors can be used, because the difference in power produced is not too large.

Effect of Injector Type and Intake Boosting on Combustion, Performance, and Emission Characteristics of a Spray-Guided Gasoline Direct Injection Engine—A Computational Fluid Dynamics Study

&lt;div&gt;In general, GDI engines operate with stratified mixtures at part-load conditions enabling increased fuel economy with high power output, however, with a compensation of increased soot emissions at part-load conditions. This is mainly due to improper in-cylinder mixing of air and fuel leading to a sharp decrease in gradient of reactant destruction term and heat release rate (HRR), resulting in flame quenching. The type of fuel injector and engine operating conditions play a significant role in the in-cylinder mixture formation. Therefore, in this study, a CFD analysis is utilized to compare the effect of stratified mixture combustion with multi-hole solid-cone and hollow-cone injectors on the performance and emission characteristics of a spray-guided GDI engine.&lt;/div&gt; &lt;div&gt;The equivalence ratio (&lt;i&gt;ϕ&lt;/i&gt;) from 0.6 to 0.8 with the constant engine speed of 2000 rev/min is considered. For both injectors, the fuel injection pressure of 200 bar is used with 60° spray-cone angles. For lean boosting conditions, intake pressures of 1 bar, 1.2 bar, and 1.4 bar are maintained for 0.8 equivalence ratio cases for both injectors. Results from the CFD analysis are compared with those of the available experimental results with good agreement. Analyzing the results, naturally aspirated and intake boosting conditions for &lt;i&gt;ϕ&lt;/i&gt; of 0.8, mixture distribution and flame propagation for the multi-hole solid injector are better than hollow-cone injector. Also, for the &lt;i&gt;ϕ&lt;/i&gt; of 0.8, naturally aspirated mode, the soot emissions by the hollow-cone injector are higher by about 90%, and the NO&lt;sub&gt;x&lt;/sub&gt; emissions are higher by about 19% compared to that of the multi-hole solid-cone injector. Under boosted intake pressure conditions, for the hollow-cone injector, the soot emissions are higher by about 97%–99%, and NO&lt;sub&gt;x&lt;/sub&gt; emissions are higher by about 7%–6% compared to the multi-hole solid-cone injector. Also, HC and CO emissions are considerably lower for the hollow-cone injector than that of the multi-hole solid-cone injector.&lt;/div&gt;

Influence of the non-equal aligned nozzles for fuel injection inside the supersonic combustion chamber

The importance of fuel mixing for the progress of the scramjet engine is indisputable. The present article shows the importance of the non-equal multi-injector system for effective fuel distribution and flame holding inside the combustion segment of a scramjet engine. The supersonic air and fuel jet flow in the non-equal nozzle arrangement is simulated via computational fluid dynamic technique. Two injector types of circular and rectangular nozzle have been analyzed to attain flow characteristics of hydrogen jets at supersonic cross flow. Mach contour is also analyzed for these jet arrangements to show the interface of the jet in the non-equal jet arrangement. Besides, addition of internal air jet is also simulated and evaluated in this research. Our investigation shows that the diffusion height of the fuel jet is higher when a rectangular non-equal nozzle is applied. The circular nozzle is more active in the spreading of the fuel in the combustor and the use of an internal air jet effectively increases fuel in a combustor of the scramjet.

Adaptation and Validation of Injection Rate Predictive Model for Solenoid Type Injectors with Different Nozzle Geometry

The present research analyses the injection rate of a direct rail injection diesel engine, focusing specifically on the influence of the nozzles and various operating conditions from real road tests on the rate of injection. A diesel injector test bench was used for feedback with real data from the test vehicle under real road conditions. An analysis of the behaviour of the injection rate was carried out using the zero-dimensional model. This model generated a predictive model that incorporated the five variables identified through a developed multivariate analysis of variance, showing a high correlation of dependence between variations in injection pressure, the diameter of the holes, and the number of holes with greater representativeness. The results obtained showed that the nozzle geometry and the physical properties of the fuel had a direct effect on the injection rate. This analysis enriches the understanding of fuel injection and its effects on diesel engine performance by providing an analysis of the system components that influence the injection rate and generating a simple tool to feed thermodynamic diagnostic models. The proposal model may be used as an input in thermodynamics predictive models and reduce the simulation load in computational fluid dynamics predictive models.

An Innovative Retrofit Design for Energy Efficiency and Emission Reduction: MAN B&amp;W Marine Engine Slide Fuel Injector

Background:: The fuel injector is one of the most essential parts in marine diesel engines. For MAN B&amp;W two-stroke engines, the conventional fuel injector, due to the existence of sac volume, can result in problems such as increased emission and fuel consumption and shortened service life of combustion chamber components. Objective:: The MAN B&amp;W marine engine slide-type fuel injector is a structural retrofit of conventional injectors, improving diesel engine combustion conditions, fuel efficiency, and emission reduction in hydrocarbon, NOx, smoke, and particulate matter by eliminating sac volume with patented technology. Methods:: This study employed a comparative analysis approach to evaluate the performance of conventional fuel injectors versus slide-type fuel injectors in MAN B&amp;W two-stroke engines. Data collection involved practical experiences, onboard operations, and analysis of fuel efficiency, emission reduction, and combustion improvement. The structural differences and operational advantages of both injector types were examined to assess the environmental benefits and economic implications of adopting slide fuel injectors. Recommendations for the gradual replacement of conventional injectors with slide-type injectors were based on empirical data and industry best practices. Results:: Slide fuel injectors obtain a reduction of about 75% of the HC emissions at all loads. The slide fuel injector significantly decreases the smoke emission level at low engine load, at 25% load. A reduction in PM of up to 50% has been confirmed, and slide fuel injectors can reduce NOx emission by approximately 15% on average. result: The smoke emission level at low engine load, at 25% load in particular, is greatly decreased by slide fuel injector. Conclusion:: Slide fuel injectors, with a granted patent, are commonly used in marine low-speed engines due to their advantages.

Flow field reconstruction from spray imaging: A hybrid physics-based and machine learning approach based on two-phase fluorescence particle image velocimetry measurements

The interaction between liquid spray and the surrounding air is crucial in fluid research, especially in the study of fuel spray and combustion. However, the fuel spray–air interaction is a complex process influenced by multiple factors, including fuel type, fuel injection pressure, and fuel temperature. These factors are coupled together, making it challenging and time-consuming to accurately capture the spray–air data using traditional experimental methods alone. The current study proposes a hybrid physics-based and machine learning model for utilizing spray images to reconstruct ambient flow fields. The novelty of this work lies in leveraging the spatial characteristics of spray and airflow data to optimize feature extraction and reduce unnecessary nonlinearity in the model. Consequently, the model offers complementary advantages, improving model interpretability and reducing its reliance on massive data. The training dataset is collected using a combined diagnostic approach, utilizing Mie-scattering imaging and fluorescence particle image velocimetry. The liquid spray and the ambient air velocity field are measured simultaneously under a wide range of experimental conditions, including different fuel types, fuel injection pressures, and fuel temperatures. The reconstruction results are validated against unseen experimental data. In general, the reconstruction results indicate that the model is accurate, fast, and robust for different fuel conditions and injector types. It provides an innovative way to reconstruct airflow fields based on spray images (spray density distribution). These findings highlight the potential of integrating physics-based and machine learning methods for multiphase flow diagnostics, paving the way for broader data-driven applications in fluid research.

Experimental Study of Spray and Combustion Characteristics in Gas-Centered Swirl Coaxial Injectors: Influence of Recess Ratio and Gas Swirl

The spray and combustion characteristics of a gas-centered swirl coaxial (GCSC) injector used in oxidizer-rich staged combustion cycle engines were analyzed. The study focused on varying the recess ratio, presence of gas swirl, and swirl direction to improve injector performance. The impact of the recess ratio was assessed by increasing it for gas jet-type injectors with varying momentum ratios. Gas-swirl effects were studied by comparing injectors with and without swirl against a baseline of a low recess ratio gas injection. In atmospheric pressure-spray experiments, injector performance was assessed using backlight photography, cross-sectional imaging with a structured laser illumination planar imaging technique (SLIPI), and droplet analysis using ParticleMaster. Increasing the recess ratio led to reduced spray angle and droplet size, and trends of gas swirl-type injectors were similar to those of high recess ratio gas jet-type injectors. Combustion tests involved fabricating combustion chamber heads equipped with identical injectors, varying only the injector type. Oxidizer-rich combustion gas, produced by a pre-burner, and kerosene served as propellants. Combustion characteristics, including characteristic velocity, combustion efficiency, and heat flux, were evaluated. Elevated recess ratios correlated with increased characteristic velocity and reduced differences in the momentum–flux ratios of injectors. However, increasing the recess ratio yielded diminishing returns on combustion efficiency enhancement beyond a certain threshold. Gas swirling did not augment characteristic velocity but notably influenced heat flux distribution. The trends observed in spray tests were related to combustion characteristics regarding heat flux and combustion efficiency. Additionally, it was possible to estimate changes in the location and shape of the flame according to the characteristics of the injector.

Comparison of pressure-based flame describing functions measured in an annular combustor under self-sustained oscillations and in an externally modulated linear combustor

One important aspect in the analysis of combustion instabilities in multiple-injector annular systems is that of representing such oscillations with a linear array of injectors. This issue is considered in the present work by comparing flame dynamics in a self-sustained oscillations situation in the annular configuration MICCA-Spray, with experiments carried out in TACC-Spray, a rectangular combustor equipped with five injectors externally modulated by driver units. In the annular system, the coupling mode is azimuthal, and in the linear array, the flames are submitted to a transverse acoustic field. An original method is used to change the limit-cycle pressure oscillations amplitude in the annular system and favor a standing mode with a well-defined nodal line position. It consists in using different arrangements of two types of injectors, leading to various azimuthal staging patterns. The range of pressure oscillation amplitudes is swept in TACC-Spray by changing the external acoustic forcing level. It is thus possible to compare the flame dynamics in forced and self-sustained situations using these two experimental facilities. This is done by examining flame describing functions (FDFs) based on downstream pressure fluctuations measured in the two configurations for different pressure oscillation amplitudes. The trends observed in the two systems are in good agreement, and there is a reasonably good match between the values of the gains and phases determined in the two configurations. The pressure-based FDFs are determined for flames located at different positions with respect to the acoustic mode. It is found that the transverse or azimuthal velocity component has only a weak influence on the pressure-based FDF, the strongest impact being observed in the neighborhood of the velocity antinode. This study demonstrates the ability of a linear-array setup modulated by a transverse mode to reproduce conditions of azimuthal coupling leading to self-sustained limit cycles in an annular combustor.

Spray characteristics of a multi-slit type throttleable pintle injector with different slit heights

A pintle injector is a type of variable-area injector that has been effectively applied in throttleable rocket engines. Among the several types of pintle injectors, multi-slit type pintle injectors are advantageous in terms of combustion efficiency and suitability for continuous throttling. However, the spray characteristics of multi-slit type pintle injectors have been rarely investigated. Therefore, spray characteristics such as pressure drop, spray angle, and droplet size for a multi-slit type pintle injector were analyzed in this study based on slit height and throttling level. Cold flow experiments and numerical simulations using two types of pintle tips with different slit heights were conducted under a wide throttling range of 20–100 %. The experimental and numerical results indicated that adopting a vertically heightened slit significantly reduces the pressure drop, spray angle, and droplet size at high throttling levels, which can be beneficial in terms of combustion performance and combustion chamber durability. Moreover, changes in spray characteristics over a wide range of throttling levels can be alleviated by applying a vertically heightened slit. The numerical simulation models used in this study were validated such that these could be applied to predict the spray characteristics of multi-slit type pintle injectors.

Industrial wastewater treatment using venture injector type Micro-bubble aeration as a reduction of dissolved Iron (Fe2+) levels

Water quality problems that are often encountered, especially by-product wastewater resulting from industrial processes that do not meet the requirements for wastewater quality standards. Iron levels in wastewater can cause the water to turn brownish yellow and produce an unpleasant odor, which of course has a big impact on the environment. Therefore, it is necessary to implement a treatment process to reduce the iron level in the water, ensuring that the water is safe when discharged into the environment. The purpose of this research is to analyze the initial parameters of temperature, pH, TDS, TSS, dissolved oxygen (DO) and dissolved iron (Fe2+) in industrial waste water and then wanted to know whether the venture injector type micro bubble aeration process was able to increase the value of dissolved oxygen (DO) and decrease the dissolved iron content (Fe2+) in wastewater and to know the micro bubble type aeration process Venture injectors are the best to use. The research was conducted with an experimental design using a completely randomized design (RAL) with two factors: air flow (2 LPM, 4 LPM, and 6 LPM) and aeration time (0 minutes, 15 minutes, 30 minutes, 45 minutes, and 60 minutes), each with two repetitions. In the results of the initial parameter analysis, the pH value was 8.02 (alkaline), the temperature value was 28°C, the TDS value was 1548.3 mg/L, the TSS value was 291 mg/L, the DO value was 0.1 mg/L and dissolved iron (Fe2+) of 7.453 mg/L. After conducting research, it was found that the venture injector type micro bubble aeration process was able to increase the value of dissolved oxygen (DO) and reduce dissolved iron (Fe2+) in industrial waste water, the best increase in dissolved oxygen (DO) at 6 LPM air flow for 60 minutes was able to increase oxygen dissolved (DO) to 2.40 mg/L. The most efficient and effective reduction in the value of dissolved iron (Fe2+) at 6 LPM air flow with a time of 15 minutes was able to reduce the value of dissolved iron by 84.42%.

Comparative Analysis of Three Preloaded and One Manual Injector for Intraocular Lens Implantation

Purpose: to evaluate the incision width and implantation time of different IOL models using three preloaded and one manual injector. Patients and methods. 146 patients (160 eyes) including 94 females and 52 males were included in a prospective study. Group I — Isert® (28 patients, 32 eyes); Group II — Multisert® (27 patients, 30 eyes); Group III — Autonome® (45 patients, 50 eyes) and Group IV — Monarch® (46 patients, 48 eyes). mean age of patients was 71.8 ± 11.7 years, follow-up period — 3.0 ± 0.2 months. Results. There were no significant differences (p &gt; 0.05) between the groups when comparing the incision width before IOL implantation. After lens implantation, the incision width in group I was significantly higher than in groups II (p = 0.04), III (p = 0.037) and IV (p = 0.029). There were no significant differences in incision width after IOL implantation between groups II, III, and IV (p &gt; 0.05). The average increase in corneal incision width in group I was 0.6 mm, and for groups II, III, and IV it ranged from 0.2 to 0.3 mm. Groups II, III, and IV showed lower values of surgically induced astigmatism compared with group I (0.47 ± 0.06 D, 0.41 ± 0.06 D, and 0.44 ± 0.07 D compared with 1.12 ± 0.17 D, respectively; p &lt; 0.05 for all groups). No significant differences were found between groups II, III, and IV. Minimum implantation time was observed for groups II and III, maximum for groups I and IV, with a mean difference of about 30 seconds. Differences when comparing the mean IOL implantation time were not statistically significant (p &gt; 0.05). Conclusion. This paper presents the first worldwide comparative analysis of four IOL implantation systems, including Isert®, Multisert®, Autonome®, and Monarch®. The new Multisert® IOL implantation system has similar advantages to the known monofocal IOL injectors with respect to corneal incision width, surgically induced astigmatism magnitude, and time required for IOL implantation. IOL implantation time did not depend on the type of implantation (hydro- or viscous) and the type of injector.

Три предварительно заряженных и один ручной инжектор для имплантации ИОЛ: сравнительный анализ

Aim. To evaluate the incision width and implantation time of different IOL models using three preloaded and one manual injector. Material and methods. 146 patients (160 eyes) including 94 females and 52 males were included in a prospective study. Group I – Isert® (28 patients, 32 eyes); Group II – Multisert® (27 patients, 30 eyes); Group III – Autonome® (45 patients, 50 eyes) and Group IV – Monarch® (46 patients, 48 eyes). mean age of patients was 71.8 ± 11.7 years, follow-up period – 3 ± 0.2 months. Results. There were no significant differences (p &gt; 0.05) between the groups when comparing the incision width before IOL implantation. After lens implantation, the incision width in group I was significantly higher than in groups II (p = 0.04), III (p = 0.037) and IV (p = 0.029). There were no significant differences in incision width after IOL implantation between groups II, III, and IV (p &gt; 0.05). The average increase in corneal incision width in group I was 0.6 mm, and for groups II, III, and IV it ranged from 0.2 to 0.3 mm. Groups II, III, and IV showed lower values of surgically induced astigmatism compared with group I (0.47 ± 0.06, 0.41 ± 0.06, and 0.44 ± 0.07 D compared with 1.12 ± 0.17 D, respectively; p &lt; 0.05 for all groups). No significant differences were found between groups II, III, and IV. Minimum implantation time was observed for groups II and III, maximum for groups I and IV, with a mean difference of about 30 seconds. Differences when comparing the mean IOL implantation time were not statistically significant (p &gt; 0.05). Conclusion. This paper presents the first worldwide comparative analysis of four IOL implantation systems, including Isert®, Multisert®, Autonome®, and Monarch®. The new Multisert® IOL implantation system has similar advantages to the known monofocal IOL injectors with respect to corneal incision width, surgically induced astigmatism magnitude, and time required for IOL implantation. IOL implantation time did not depend on the type of implantation (hydro- or viscous) and the type of injector. Keywords: cataract, injector, Isert®, Multisert®, Autonome®, Monarch®, surgically induced astigmatism

FERTIGATION DISTRIBUTION WITH LOW PRESSURE MULTIGATE IRRIGATION SYSTEMS IN A SUGARCANE AGROECOSYSTEM

In the state of Veracruz, Mexico, low sugarcane yields are reported despite the high use of inputs. This results in economic losses and environmental pollution. A fertigation system designed at the Colegio de Postgraduados (COLPOS) Campus Veracruz was established to determine the uniformity and stability of fertilizer distribution in the sugarcane crop. This study was carried out in a sugarcane plot with a farmer participant. Three levels of valve openings at the injector inlet (1/3, 2/3, and 3/3) were tested to determine the homogeneity of fertigation at the outlet of the gates and the stability of the system over time. Samples of water-fertilizer mixture were taken at the outlet of the gates. They were analyzed in the laboratory with a UV-visible spectrophotometer at 202 nm for nitrogen. It was found that the 1/3 and 3/3 valve position openings caused instability in the system. For the 2/3 opening with p = 0.359, no statistical difference (α= 0.05) was found during the time of emptying the container of the water-fertilizer mixture. Therefore, the fertigation system proved to be stable with a valve opening close to 2/3. Using the valve openings, the flow rate of water-fertilizer entering the system is uniformly mixed at the outlets of the multi-gate pipeline that pours into the crop furrows (p = 0.474 and α = 0.05). It can be concluded that in fertilization using a low-pressure irrigation system, nitrogen fertilizer is uniformly distributed when a Venturi type injector is used in a sugarcane agroecosystem with a valve opening close to 2/3.

Combustion characteristics of a dual-mode ramjet engine with a supersonic aerodynamic ramp injector

The combustion characteristics of a liquid-hydrocarbon-fueled dual-mode ramjet combustor with a new injector, including a cavity-type flame holder, were investigated under inflow conditions of M 1.8, total pressure of 590 kPa, and total temperature of 930 K. The newly proposed injector uses various injection methods, such as an aerodynamic ramp, pre-mixing chamber, barbotage gas, and supersonic nozzle. The aerodynamic ramp injection method consists of four injectors with inclination angles of 40° and 80° and toe-in angles of 30° and 60°. This was adopted to increase the penetration height of the fuel while minimizing the total pressure loss. A pre-mixing chamber with a barbotage gas injection device was employed to enhance atomization and fuel–air mixing. In addition, a contoured Mach 3 supersonic nozzle was used to obtain a higher momentum through acceleration. For performance comparison, a combustor with a pre-mixing chamber and barbotage gas was used in the same manner, but injected by a cylindrical nozzle with a 15-degree of transverse angle. The ignition was initiated by a torch ignitor installed on the cavity floor with hydrogen pilot fuel. Once combustion stabilized, only the main liquid fuel was supplied. The Mach number was calculated using quasi-one-dimensional analysis based on the measured wall pressures and inlet conditions. The results showed that the model combustor with two types of injectors operated in the ramjet mode, which was subsonic near the flame holder and supersonic at the exit of the combustor. At the combustor outlet, the total pressure according to the equivalence ratio of 0.25 to 0.56, the newly proposed injector case showed a higher pressure level, steep increase, and more uniform pressure distribution than the baseline injector from the measurement result of the pitot pressure rake at the combustor exit.

Effects of extruded lobe-nozzle on fuel mixing of transverse air and fuel jets at supersonic flow

Improving fuel mixing is a crucial step in increasing the flight speed of high-velocity vehicles. This study aims to investigate the importance of an extruded single lobe-nozzle in facilitating efficient fuel mixing inside the combustion chamber of a scramjet engine. Computational techniques are used to model compressible supersonic flow with transverse air and fuel jet released from the extruded nozzle in the combustion chamber. The study extensively analyzes the effects of injector types (2-lobe, 3-lobe, and 4-lobe) of the extruded injector on shock interaction and flow features of air and fuel jet behind the injectors. Due to the presence of the extruded nozzle, shock interactions are strengthened, and the vortex feature behind the nozzle is extended. Fuel penetration and mixing are fully discussed to obtain an efficient model for fuel injection in the combustion chamber. Additionally, the study discloses the influence of the height of the extruded lobe injector on fuel mixing. The results of our study indicate that the lobe injector improves fuel mixing more efficiently behind the nozzle, while a circular nozzle is efficient for fuel mixing far downstream of the injector.