Injection Nozzle Research Articles

An experimental study on the effect of gas injection configuration on flow characteristics in high viscosity oil columns

AbstractGas‐viscous liquid bubbly and slug flow are very common in petroleum, chemical, bioengineering, polymer, and food processing. However, there is a major knowledge gap in two‐phase flow research in the design of gas injectors/distributers in very high viscosity oil systems. The present study investigates the effect of gas injection methods in columns containing very high viscosity oils (i.e., realistic liquids), and more specifically using 360 Pa · s viscosity oil in a 240‐mm diameter column. The effects that the radial positioning, number of gas nozzles, and their distance from each other have on the structure of the flow in viscous liquids are presented in detail. Electrical capacitance tomography (ECT) is used to extract experimental data. Void fraction, bubble velocity, frequency, liquid film thickness, and bubble length were measured and analyzed at different radial gas injection positions. It has been observed that bubble length increases significantly by 0.3 m when the injection nozzle is located next to the wall of the pipe. Bubble velocity and length also increase by 0.217 m/s and 3.6 m, respectively, with increasing gas flowrate when multiple injection points are used. Increasing the distance between the gas injection points increased bubbles' length by 1.2 m. Bubbles' velocity and frequency (at higher gas flow rate) were also increased.

Numerical simulation of cavitating flow in maritime high-pressure direct fuel injection nozzles and assessment of cavitation-erosion damage

The internal flow of Heavy Fuel Oil (HFO) in two maritime direct fuel injector nozzles is studied by 3D flow simulations for the assessment of erosion-sensitive wall regions. The nozzle geometries differ in number, diameter and inclination angle of holes as well as sac wall curvature. Long-term endurance experiments reveal characteristic damage locations for both nozzles. Simulations are performed by a compressible density-based flow solver with a barotropic cavitation model to capture shock wave dynamics. Real geometries and the entire injection cycle with time-dependent rail pressure and transient needle movement are considered. A statistical evaluation of individual collapsing voids in terms of their condensation rate yield an erosion probability that is compared against experimental damage locations. Due to the scatter in the values of viscosity of real fuels a viscosity variation is carried out, which shows that while a lower viscosity leads to a rise of erosion probability, the location of erosion-sensitive wall zones is not significantly changed. The analysis of 3D velocity and void field evolutions motivates the introduction of distinct injection sub-phases of the entire cycle. Erosion probability is separately evaluated within each sub-phase. By this simulation procedure, experimentally found erosion spots are associated with particular sub-phases and can be traced back to characteristic flow and void structures that are linked to particular nozzle geometry features.

Organization of Six-Cylinder Tractor Diesel Working Process

The purpose of the work is to consider the organization of the working process of six-cylinder diesel engines with a power of 116 and 156 kW and exhaust gas recirculation. The following systems and components were used in the experimental configurations of the engine: Common Rail BOSСH accumulator fuel injection system with an injection pressure of 140 MPa, equipped with electro-hydraulic injectors with seven-hole nozzle and a 500 mm3 hydraulic flow; direct fuel injection system with MOTORPAL fuel pump with a maximum injection pressure of 100 MPa, equipped with MOTORPAL and AZPI five-hole nozzle injectors; two combustion chambers with volumes of 55 and 56 cm3 and bowl diameters of 55.0 and 67.5 mm, respectively; cylinder heads providing a 3.0–4.0 swirl ratio for Common Rail system, 3.5–4.5 for mechanical injection system. The recirculation rate was set by gas throttling before the turbine using a rotary valve of an original design. The tests have been conducted at characteristic points of the NRSC cycle: minimum idle speed 800 rpm, maximum torque speed 1600 rpm, rated power speed 2100 rpm. It has been established that it is possible to achieve the standards of emissions of harmful substances: on the 116 kW diesel engine using of direct-action fuel equipment and a semi-open combustion chamber; on the 156 kW diesel using Common Rail fuel supply system of the Low Cost type and an open combustion chamber.

Preloaded injectors used in a clinical study: videographic assessment and laboratory analysis of injector nozzle damage.

To evaluate quality and duration of implantation of 2 preloaded intraocular lens (IOL) injectors and assess postimplantation damage. The David J. Apple Center for Vision Research, Department of Ophthalmology, University of Heidelberg, Heidelberg, Germany. Prospective, randomized, comparative study with laboratory investigation. Implantation videos and postuse injectors from 60 paired eyes of 30 bilateral cataract patients were included. Patient eyes were randomly assigned for implantation with 2 different preloaded injectors: the AutonoMe with a Clareon IOL (Alcon Laboratories, Inc.) and the iSert with a Vivinex IOL (Hoya Corp.). Videos were reviewed for events during the implantation procedure, and the duration of each step of implantation. Injector nozzles were examined under light and scanning electron microscopy. Damage was graded and correlated with the IOL power. Three months postoperatively IOLs were assessed for material changes. IOL delivery was without any critical events in 60 of the 60 eyes. The implantation took 56 seconds with the AutonoMe and 44 seconds with the iSert (P < .05). Most AutonoMe injectors (29; 97%) showed no damage or slight deformation. In most of the iSert injectors (25; 80%), short or extended cracks were present, and damage lengths correlated with the IOL power. All IOLs were free of material changes, including glistenings, 3 months postoperatively. Both preloaded IOL injectors allowed a safe and convenient IOL delivery. Implantation of the Clareon IOL took, on average, slightly longer than that of the Vivinex IOL, mostly due to a slower IOL unfolding. The AutonoMe showed less nozzle tip damage than that of the iSert.

Performance of CI Engine Using Swirl Type Retrofit

Due to its higher thermal efficiency diesel engines are used worldwide in transportation, agriculture and many. The problem associated with these diesel engines are less efficiency and release of toxic emissions like CO, HC and NOx to the atmosphere. These problems can be overcome by use of alternative fuels and by engine modification. Modification of fuel spray is one of the methods to achieve complete combustion of fuel, which helps in achieving higher efficiency and reduced toxic emissions. This work is carried out by using an attachment for fuel injector known as retrofit. Experiments were conducted using retrofit attached to fuel injector nozzle and found to be increased in efficiency of the engine and reduced toxic emissions when compared with conventional injector without retrofit.

Influence of Nozzle Hole Geometry of CI Engines Performance and Emission Parameters Fuelled by Diesel and Biodiesel-A Review

In the quest to reduce hazardous pollutant emissions and environmental impact, various renewable alternative fuels derived from bio-based sources have entered the market. Biodiesel, a vegetable oil ester, has gained a lot of popularity and attention for diesel engine applications. The performance of diesel engine and emission characteristics are closely linked with fuel atomization and spray pattern of fuel injection nozzles. In modern engines various orifices with different designs are used. In a diesel engine, the shape of the diesel fuel injection nozzle and the fuel flow parameters in the nozzle have a considerable impact on the processes of fuel atomization, combustion, and exhaust emissions. The main focus of this study is to explore how number of nozzle hole and shape affects the performance of diesel engine, combustion, and emissions for both Biodiesel and diesel fuels.

PHYSICO-MATHEMATICAL MODEL OF VENTILATION SYSTEM FORCING OF CLEAN AIR IN LIVESTOCK PREMISES

The microclimate of livestock facilities is determined by a range of factors, including physical parameters: humidity, atmospheric pressure, light, temperature, speed and direction of air movement. Air quality plays an important role - the concentration of harmful gases and microorganisms, dust. The parameters of the microclimate affect not only the productivity of animals, but also their health. In order not to harm the health of the animal and achieve the desired performance, these parameters must be adjusted with special equipment. The purpose of research is to substantiate the design and technological parameters of the ventilation system for the injection of clean air in livestock premises to ensure uniformity of its distribution. The article presents the results of research to substantiate the design and technological parameters of the ventilation system for the injection of clean air in pig farms to ensure uniformity of its distribution. As a result of analytical studies of the parameters of the slit of the nozzle for air injection from the condition of uniform air distribution, an approximate equation for its width δ'y depending on the y-axis location for different effective diameters of the nozzle d'H. For the system of injection of clean air the condition according to which at opening of all discharge valves it is necessary to provide uniformity of distribution of air by system of injection is set. For this purpose the central air duct for air injection should have a wedge-shaped form of length L' with constant height b', with initial width a'N and final a'1. As a result of theoretical researches dependences of a lateral angle of a wedge θ the central air duct of system of injection of pure air and its width on the end a1' on distance between adjacent sections L'0, width of the central air duct on its beginning aN' and quantity of branch pipes for injection N' are established. As a result of analytical studies of pressure losses of the ventilation system of pure air injection of the pigsty, the dependences of changes in pressure losses Δp2 and power NW2 required for pumping air through it on the width of the central air duct aN, air flow through the system qk, length between system pipes L0 and their number N.

The influence of in-cylinder flows and bulk gas density on early Spray G injection in an optical research engine

A well-characterized multi-hole gasoline injector, the Engine Combustion Network’s (ECN) Spray G injector, was investigated in an optically accessible research engine under four motored operating conditions with early injection. The experiments were conducted at intake pressures of [Formula: see text] and [Formula: see text], nearly matching the ECN’s standard early injection operating conditions, Spray G2 (flash boiling) and Spray G3 (early injection), respectively. This was combined with two engine speeds at [Formula: see text] and [Formula: see text]. Using particle image velocimetry and volumetric Mie scatter imaging, the in-cylinder flows were evaluated and the effects on the spray morphology were characterized. The in-cylinder flow was evaluated to understand the spray-flow interaction, including the turbulent kinetic energy. Little effect on turbulent energy was observed in the region examined near the exit of the fuel injector nozzle shortly after injection. Mie scatter imaging was used to characterize the spray morphology and wall wetting was clearly visible on the spark plug. Cyclic variability of the sprays was found to be insignificant; and major differences in spray morphology are attributed to the in-cylinder velocity and intake pressure at the time of injection. Decreasing the bulk gas density by decreasing the intake pressure had a number of effects on the evolution of the spray including faster evaporation, increased axial liquid penetration, and decreased spray angle. Increasing the in-cylinder flow magnitudes by increasing the engine speed had a similar effect on spray morphology by also increasing the evaporation rate, increasing the axial penetration, and decreasing the spray opening angle. Comparison of the motored spray cases with a no-flow case (when the fuel is sprayed into the engine without the piston present) further illustrated the extent to which the intake flow influenced the spray shape.

Numerical Analysis of the Interactions between Plasma Jet and Powder Particles in PS-PVD Conditions

Plasma spray-physical vapor deposition (PS-PVD) refers to a very low-pressure (~100 Pa) deposition process in which a powder is injected in a high-enthalpy plasma jet, and mostly vaporized and recondensed onto a substrate to form a coating with a specific microstructure (e.g., columnar). A key issue is the selection of the powder particle size that could be evaporated under specific spray conditions. Powder evaporation takes place, first, in the plasma torch between the injection location and nozzle exit and, then, in the deposition chamber from the nozzle exit to the substrate location. This work aims to calculate the size of the particles that can be evaporated in both stages of the process. It deals with an yttria-stabilized zirconia powder and two commercial plasma torches operated at different arc powers with gas mixtures of argon and helium or argon and hydrogen. First, it used computational fluid dynamics simulations to calculate the velocity and temperature fields of the plasma jets under very low-pressure plasma conditions. Then, it estimated the evaporation of the particles injected in both plasma jets assuming an isothermal evaporation process coupled with momentum and heat transfer plasma-particle models in a rarefied plasma. The calculations showed that, for different powers of the Ar–H2 and the Ar–He operating conditions of this study, the heat flux from the plasma jet to particles inside the torch is much higher than that transferred in the deposition chamber while the specific enthalpy transferred to particles is comparable. The argon-helium mixture is more efficient than the argon-hydrogen mixture to evaporate the particles. Particles less than 2 μm in diameter could be fully evaporated in the Ar–He plasma jet while they should be less than 1 µm in diameter in the Ar–H2 plasma jet.

Cold emission optimization of a diesel- and alternative fuel-driven CI engine

This paper deals with the emission optimization of a compression ignition (CI) engine during cold ambient operation. Hence, in the present study, the effect of different injector nozzle geometries and pilot injection strategies, but also the influence of intake swirl, rail pressure, exhaust gas recirculation (EGR) as well as EGR cooling on the emission behavior during cold run are investigated. Therefore, test bed experiments under steady-state cold conditions are conducted on a state-of-the-art CI single cylinder research engine (SCRE) with approximately 0.5 l swept volume representing the typical passenger car (PC) cylinder size. The cold charge air temperature of down to −8 ^{circ }hbox { C} and a low engine coolant and lube oil temperature represent a cold run close to reality. For emulating the higher friction of a typical 4-cylinder PC engine during cold run, the indicated mean effective pressure (IMEP) is increased according to a specifically developed equation and the turbocharger main equation is solved permanently to adjust the gas exchange loss. To take account of a potential future tightening of emission legislation, in addition to limited exhaust gas emissions, non-limited emissions such as carbonyls are measured as well. Since alternative fuels are able to make a significant contribution to the defossilisation of transportation, an oxygen-containing fuel, consisting of 100 % renewable blend components (HVO, ethers and alcohols) and fulfilling the EN 590 legislation is investigated under the same cold conditions in addition to the research on conventional diesel fuel.

Study on the characteristics of grinding fluid in extrusion grinding machining

Extrusion grinding machining (EGM) has become a key technology in the post-processing of micro-hole in the injector nozzle. In this paper, the pure slurry prepared from organic bentonite and the pure slurry after adding abrasive as experimental objectives, and the correlation performance has been carried out. Results showed that both pure slurry and slurry abrasive have good shear thinning characteristics, belong to pseudoplastic non-Newtonian fluid, and their rheological properties obey the power-law model. The pure slurry after stirring and shearing can restore the reticular structure in a short time, which proves that it has excellent thixotropy and meets the conditions of circulating processing of grinding fluid. In addition, the pure slurry and slurry abrasive also have good sedimentation stability, suspension capacity, and dispersion properties.

Study on cyclic variation rate of fuel flow in the nozzle during fuel injection

The fuel flow pattern in the fuel injection nozzle of diesel engine is a complex and changeable phenomenon, which is easily affected by various factors, bringing the differences of flow patterns between multiple injection cycles. To solve the above problem, a visual experimental platform of fuel injection nozzle was built, in which the 100 injection cycles of diesel engine on the same working condition were photographed via shadowgraphy to study the difference in fuel flow pattern in the nozzle by ensemble average processing method. The cyclic variation rate K of fuel flow pattern is defined. Results demonstrate that the fuel flow pattern tends to be the same in multiple fuel injection cycles, but there is a strong randomness at the starting of injection and after ending of injection; the K can be reduced by decreasing the injection pressure and the inclination angle of orifice, so that the fuel flow pattern in the nozzle tends to be consistent.

Nozzle configuration and in-cylinder pressure effects on fuel spray behaviour: studies using a rapid cycling machine

Efforts to improve the efficiency of internal combustion engines in applications such as heavy-duty vehicles where electric propulsion is currently unfeasible or need complementing are essential. However, studying the conditions of actual internal combustion engines whilst accessing their combustion chambers whilst they are in operation remains difficult. To allow for the characterization of practical operating conditions of diesel engine designs, detailed studies examining the influence of the injector nozzle configuration, peak in-cylinder pressure conditions, and fuel injection pressure values up to 25% greater than those hitherto typically reported using rapid cycling machines for diesel spray diagnosis were carried out. A rapid cycling machine using a production diesel engine piston design, equipped with optical windows and fitted with a high-pressure common rail fuel injection equipment was used with temporal spray liquid and vapour penetration values obtained using Schlieren and Mie scattering imaging techniques for injector nozzles of various k-factor values. Even though the effects of the different injector nozzle conicity values on the fuel spray liquid and vapour penetration values observed were not significant, the studies supported the use of such methods to evaluate the piston and cylinder wall wetting which can have significant effects on the emissions and fuel consumption from internal combustion engines. These are also useful for internal combustion engine design and numerical spray code development.

Experimental investigation and modeling of fuel wall films from gasoline direct injection nozzles

Experimental investigation and modeling of fuel wall films from gasoline direct injection nozzles

Influence of Combustion Chamber Shapes and Nozzle Geometry on Performance, Emission, and Combustion Characteristics of CRDI Engine Powered with Biodiesel Blends

Environmentally friendly, renewable, and green fuels have many benefits over fossil fuels, particularly regarding energy efficiency, in addition to addressing environmental and socioeconomic problems. As a result, green fuels can be used in transportation and power generating applications. Furthermore, being green can ably address the emission-related issues of global warming. In view of the advantages of renewable fuels, two B20 fuel blends obtained from methyl esters of cashew nutshell (CHNOB), jackfruit seed (JACKFSNOB), and jamun seed oils (JAMSOB) were selected to evaluate the performance of a common rail direct injection (CRDI) engine. Compatibility of the nozzle geometry (NG) and combustion chamber shape (CCS) were optimized for increased engine performance. The optimized CCS matched with an increased number of injector nozzle holes in NG showed reasonably improved brake thermal efficiency (BTE), reduced emissions of smoke, HC, and CO, respectively, while NOx increased. Further combustion parameters, such as ignition delay (ID) and combustion duration (CD) reduced, while peak pressure (PP) and heat release rates (HRR) increased at the optimized injection parameters. The CRDI engine powered with JAMSOB B20 showed an increase in BTE of 4–5%, while a significant reduction in HC and CO emissions was obtained compared to JACKFSNOB B20 and CHNOB B20, with increased NOx.

Macrostructure and macrosegregation behavior of bloom products under various flow control modes of the casting process

Owing to the large cross-section and wide solidification-temperature zone, bloom castings of medium- and high-carbon steels are prone to severe central shrinkage and macrosegregation defects. Flow control technologies such as nozzle injection mode and electromagnetic stirring, together with the casting speed, play a key role in the as-cast macrostructure and macrosegregation distribution in bloom castings achieving soundness and compositional homogeneity of the final as-rolled products. Based on the production process of a medium-carbon-steel bloom casting and its heavy section bars, various flow control modes have been adopted in the casting production to study their effects on the semiproduct solidification structure and the carbon distribution across the bloom section and the following rolled bars. The conventional nozzle with a single straight port shows that the equiaxed crystal ratio in the casting process can only increase from 6.06% to 11.71% with the M-EMS intensity changes from 0 to 800 A, in which a shrinkage cavity and macrosegregation exist along the centerline on the strand casting. While the novel five-port nozzle has been adopted, the equiaxed crystal ratio can reach 23.1% even with the M-EMS power off, and the center cavity index drops down to grade 1.0 or below, meeting the requirement of microvoid flaw detection for the bar products. Additionally, the carbon segregation across the bloom cross-section is observed to resemble an M-shaped curve with a maximum carbon segregation index in the columnar to equiaxed transition zone instead of the popular center region. For the heavy section bars rolled from bloom casting, a similar carbon distribution pattern as the cast is observed after hot working but with an even higher centerline segregation index. Therefore, considering the special quality requirements for the subsequent hot processing, the macrostructure and pattern and intensity of macro-segregation should be regulated from the beginning of casting with a reasonable flow control mode as mentioned in the study.

Regression rate performance of paraffin wax and bees wax –Gox with varied grain configuration in a hybrid rocket motor

Purpose This paper aims to determine the regression rate using wax fuels for three different grain configurations and find a suitable grain port design for hybrid rocket application. Design/methodology/approach The design methodology of this work includes different grain port designs and subsequent selection of solid fuels for a suitable hybrid rocket application. A square, a cylindrical and a five-point star grained were designed and prepared using paraffin and beeswax fuels. They were tested in a laboratory-scale rocket with gaseous oxygen to study the effectiveness of solid fuels on these grain structures. The regression rate by static fire testing of these wax fuels was analyzed. Findings Beeswax performance is better than that of paraffin wax fuel for all three designs, and the five-slotted star fuel port grain attained the best performance. Beeswax fuel attained an average regression rate ≈of 1.35 mm/s as a function of oxidizer mass flux Gox ≈ 111.8 kg/m2 s and for paraffin wax 1.199 mm/s at Gox ≈ 121 kg/m2 s with gaseous oxygen. The local regression rates of fuels increased in the range of 0.93–1.194 mm/s at oxidizer mass flux range of 98–131 kg/m2 s for cylindrical grain, 0.99–1.21 mm/s at oxidizer mass flux range of 96–129 kg/m2s for square grain and 1.12–1.35 mm/s at oxidizer mass flux range of 91–126 kg/m2 s for a star grain. A complete set of the regression rate formulas is obtained for all three-grain designs as a function of oxidizer flux rate. Research limitations/implications The experiment has been performed for a lower chamber pressure up to 10 bar. Originality/value Different grain configurations were designed according to the required dimension of the combustion chamber, injector and exhaust nozzle of the design of a lab-scale hybrid rocket, and input parameters were selected and analyzed.

Optimization of Design and Technology of Injector Nozzles in Terms of Minimizing Energy Losses on Friction in Compression Ignition Engines

The operation of injection apparatus in self-ignition engines results from the design, manufacturing technology and wear and tear during operation. The technical state of the injector apparatus significantly affects the engine performance, fuel consumption, toxicity and smoke opacity of outlet gases. The most unreliable element of the injection apparatus is the injector nozzle, the quality of which depends on the quality of construction and production, operating conditions and the of the fuels used, etc. One of the design parameters of the injector nozzles, determining the technical state is the geometry of the nozzle holes. An attempt was made to optimize the selection of the dimensions and surface condition of the spray holes to significantly affect the flow properties of the injector nozzles and, consequently, to decide on the size and form of fuel dosed streams to individual cylinders of a self-ignition engine and the quality of fuel atomization. In work, a simulation model was developed, and the pressure losses and the mass fluid of the injected fuel were minimized for selected significant geometric features, taking into account the influence of operating conditions. With the use of Mathematica software, simulation optimization methods and methods based on evolutionary algorithms were elaborated.

Numerical Investigation of Nozzle Jet Flow in a Pelton Microturbine

The characterization of flow through Pelton hydro turbines allows the optimization of their operation and maximization of energy performance. The flow in the injector of Pelton turbines and in the free jet area (the area from the injector outlet surface to the runner bucket inlet surface) is influenced by several parameters: the geometry of injector components (nozzle and injector spear), the injector opening, and the turbine head. The parameters of the free jet flow (velocity distribution, pressure distribution, and jet spread) are reflected in the turbine efficiency. The research presented in this paper focuses on the numerical characterization of flow in the injector and the free jet of a Pelton microturbine. Three injector geometries were considered, with different nozzle diameters: 13.3 mm, 14.4 mm, and 16.3 mm. For each of these geometries, the flow was analyzed for five values of turbine head (H = 15 m, H = 20 m, H = 25 m, H = 30 m, H = 35 m) and six values of injector opening (S = 3 mm, S = 6 mm, S = 9 mm, S = 12 mm, S = 15 mm, S = 18 mm). The results of numerical simulations were used to plot injector flow-rate characteristics and injector force characteristics (the resultant force on the injector spear and the resultant force on the injector nozzle). The highest influence on the flow rate variation is given by the variation of turbine head, followed by the variation of the injector opening and the variation of the nozzle diameter. Increasing the nozzle diameter accentuates the variation of the flow rate versus the turbine head. The variation of axial velocity and pressure in the free jet is presented for four sections parallel to the outlet section of the injector. The injector openings that generate the highest values of velocity/pressure on the runner inlet surface are highlighted. The results allow optimization of functional parameters for increasing turbine efficiency and optimizing the design process of Pelton microturbines.

Spray atomization simulation of bamboo kraft black liquor with high solid content at splash-plate nozzle

Increasing the solids content of pulping black liquor burned in a furnace is a development trend of the alkali recovery system in the pulp and paper industry. However, the viscosity of kraft black liquor increases exponentially with an increase in solids content, especially in the case of non-wood pulping black liquor, such as bamboo. This brings great difficulties to the pulping system and atomization of black liquor at the splash-plate nozzle, which is a complete atomization unit constituted of a splash nozzle and a splash plate. To obtain instructive results for industry, a simulation of the atomization process was made using Fluent software for the bamboo kraft black liquor with solids contents of 70 wt% and 80 wt%, which flowed through splash nozzles with the diameter of 22 or 20 mm. The studies were conducted on the distribution of flow field in the nozzle and atomization region through changing the injection pressure and nozzle diameter. The variation of atomization characteristic parameters, such as liquid film thickness, and breakup length, were elucidated. The results reveal the relationship between spray atomization with injection pressure and nozzle diameter, which provides a theoretical basis for improving the concentration of black liquor entering alkali recovery in the future.