Nozzle Hole Diameter Research Articles

Flow Field Analysis Inside and at the Outlet of the Abrasive Head

This paper focuses on the investigation of a multiphase flow of water, air, and abrasive particles inside and at the outlet of the abrasive head with the help of computational fluid dynamics calculations and measurements. A standard abrasive head with a water nozzle hole diameter of 0.33 mm (0.013”) and an abrasive nozzle cylindrical hole diameter of 1.02 mm (0.04”) were used for numerical modelling and practical testing. The computed tomography provided an exact 3D geometrical model of the cutting head that was used for the creation of the model. Velocity fields of abrasive particles at the outlet of the abrasive head were measured and analysed using particle tracking velocimetry and, consequently, compared with the calculated results. The calculation model took the distribution of the abrasive particle diameters with the help of the Rosin-Rammler function in intervals of diameters from 150 to 400 mm. In the present study, four levels of water pressure (105, 194, 302, 406 MPa) and four levels of abrasive mass flow rate (100, 200, 300, 400 kg/min) were combined. The values of water pressures and hydraulic powers measured at the abrasive head inlet were used as boundary conditions for numerical modelling. The hydraulic characteristics of the water jet were created from the measured and calculated data. The calculated pressure distribution in the cylindrical part of the abrasive nozzle was compared with studies by other authors. The details of the experiments and calculations are presented in this paper.

Improving the performance of a diesel engine by changing injectors characteristics after reduction on the compression ratio

In order to repair internal combustion engines, sometimes it is necessary to replace the components of these engines with each other. Therefore changes in engine performance are inevitable in these conditions. In the present study, by changing the coneccting rod and the crank of the OM457 turbo diesel-fueled engine with the OM444, it was observed that the performance of the engine decreases. Numerical simulations have been carried out to study the Possible ways to mitigate this reduction. One way to achieve this goal is to change the fuel injector’s characteristics such as, fuel injector’s nozzle hole diameter, number of nozzle holes, and start time of fuel injection. In this study, the impact of these parameters on the performance and emissions of these engines were analyzed. Another scenario is an increase in inlet fuel and air by the same amount. The results indicate that By reducing the diameter of fuel injector holes and hole numbers, the performance of the engine was increased. on the other hand, the NOx emissions were increased while the amount of soot emission decreased. The same results were concluded by retarding the start time of injection. Subsequently, a case study of changing fuel injector parameters for mitigation of decreased performance was performed. These parameters were simultaneously applied, and results were compared. The performance of the engine with improved injector’s characteristics was close to the main OM457. Similar results were obtained by increasing the amount of inlet air and fuel.

Investigation of the effects of EGR rate, injection strategy and nozzle specification on engine performances and emissions of a single cylinder heavy duty diesel engine using the two color method

Abstract This study focused on the effects of EGR rate, injection pressure, injection timing, and nozzle hole diameter on the nitrogen oxidize and particulate matter in a diesel engine. The optical engine equipped with the endoscope system were used and two color method theory were applied to calculate the flame temperature and PM density from the combustion images. Parametric experiments were performed by changing the EGR rate, injection pressure, and injection timing using a reference nozzle. According to the combustion images analysis, the flame temperature was greatly reduced by increasing EGR rate. Moreover, the EGR rate significantly affects the PM oxidation rate. As a result, the higher EGR rate, the higher PM density were observed. The NOx and PM emissions showed same trend with the results of flame temperature and PM density respectively. Unlike the EGR rate, the injection pressure affected the fuel atomization. Decreasing injection pressure diminished the PM oxidation. The high PM emissions and low NOx emissions were observed with low injection pressure. Retarding injection timing decreased both the flame temperature and PM density because of long ignition delay and low cylinder pressure. As the lack of time for the PM oxidation, retarding injection timing increased the PM emissions which showed trade-off relationship with the NOx emissions. Nozzle hole diameters were compared for various experimental conditions. Regardless of experimental conditions, the smaller nozzle hole diameter that had superior fuel atomization showed the high flame temperature and low PM density. The NOx and PM emissions showed same trend with the optical results.

Simulations of methanol fueled locomotive engine using high pressure co-axial direct injection system

Methanol has emerged as a strong alternate fuel candidate, which can meet future fuel requirements for locomotive traction. Simulation approach is an excellent tool for preliminary technical feasibility assessment of alternative fuels compared to time consuming experiments. The objective of this study was therefore to assess the feasibility of 90% diesel displacement by methanol (on energy basis) in the ALCO-251 locomotive engines, the workhorse of Indian Railways (IR). In the first phase of this study, base model of ALCO-251 locomotive engine was prepared in 1-D simulation software (GT-Power), which was validated using the experimental data of mineral diesel provided by Research Designs and Standards Organization (RDSO), which is the R&D wing of IR. Locomotive engine works on eight different engine speeds at different notches: 350 rpm (1st Notch), 450 rpm (2nd Notch), 550 rpm (3rd Notch), 650 rpm (4th Notch), 750 rpm (5th Notch), 850 rpm (6th Notch), 950 rpm (7th Notch), 1050 rpm (8th Notch). In the second phase of the study using this validated model, a co-axial injector was used where methanol was used as the primary fuel, and diesel was used as the secondary fuel for pilot injection using Co-axial High Pressure Direct Injection (HPDI) method. For simulations, methanol and diesel injectors were housed in a single injector body of the co-axial injector, but they had individual controls. Co-axial injector was actuated such that first it injected diesel in hot air-environment to initiate the combustion, followed by injection of methanol as the main motive fuel. Base model simulated the engine performance, emissions, and combustion characteristics quite well, which were in good agreement with the experimental data. Pareto optimized dimensions of the co-axial injector were 0.486 mm nozzle hole diameter, and 3 holes for pilot diesel injection, and 0.544 mm nozzle hole diameter, and 5 holes for methanol injection. HPDI of Methanol with Pilot Diesel Injection Model with optimized injector dimensions exhibited in-cylinder pressure curve shapes similar to the base model with similar/ superior torque characteristics, higher brake thermal efficiency, and lower NOx emisssions. Inevitably, 1-D simulation for the locomotive engine represented a potential method to achieve similar/ better engine performance, combustion and emission characteristics via this new fuel injection concept, using high pressure co-axial direct injection system.

Diesel spray and combustion of multi-hole injectors with micro-hole under ultra-high injection pressure – Non-evaporating spray characteristics

Increasing the injection pressure and reducing the nozzle hole diameters can increase the thermal efficiency of diesel engines (DI). To understand the spray characteristics under ultra-high injection pressure, the spray characteristics of multi-hole injectors with different diameters were investigated under different injection pressures. The results show that the injector with a larger hole diameter has a larger injection delay and a longer injection rate rise and fall time. The injection pressure has a small effect on the injection delay. As the injection pressure increases, the injection rate rise and fall time decreases. Increasing the injection pressure and the hole diameter increases the instability of the spray. The penetration of the injectors with different hole diameters is similar in the initial stage of injection. The penetration increased with the increase of the injection pressure. However, the effect of the high injection pressure on the increase of the penetration becomes weak. The injectors with a larger nozzle hole diameter displayed a larger penetration, spray angle, spray cone angle, and spray area. The micro-hole injector under the ultra-high injection pressure, the expansion of the middle of the spray caused a larger spray angle and spray area. A larger nozzle hole diameter and injection pressure promotes an increase in the gas mass rate. But the injector with the micro-hole diameter has a better ṀA/ṀF ratio and a lower average spray equivalent ratio under ultra-high injection pressure. Naber and Siebers’ penetration model and Inagaki and Mizuta's spray angle model with modified parameters showed the better prediction effect under all experimental conditions.

Effect of Jet-Jet Angle on Combustion Process of Diesel Spray in an RCEM

<div class="section abstract"><div class="htmlview paragraph">The effects of jet-jet angle on the combustion process were investigated in an optical accessible rapid compression and expansion machine (RCEM) under various injection conditions and intake oxygen concentrations. The RCEM was equipped with an asymmetric six-hole nozzle having jet-jet angles of 30° and 45°. High-speed OH* chemiluminescence imaging and direct photo imaging using the Mie scattering method captured the transient evolution of the spray flame, characterized by lift-off length and liquid length. The RCEM operated at 1200 rpm. The injection timing was -5°ATDC, and the in-cylinder pressure and temperature were 6.1 MPa and 780 K at the injection timing, respectively, which achieved a short ignition delay. The effects of injection pressure, nozzle hole diameter, and oxygen concentration were investigated. The results show that the liquid and lift-off length of the jet-jet angle of 30° were shorter than those of the jet-jet angle of 45°, irrespective of injection conditions and oxygen concentration. Particularly, when the injection rate was high with high injection pressure and a large nozzle hole, the liquid and lift-off length rapidly and simultaneously decreased, but when the injection pressure was low or the nozzle hole diameter was small, the lift-off length decreased first, and then the liquid length decreased.</div></div>

The effect of nozzle hole diameter of 3D printing on porosity and tensile strength parts using polylactic acid material

Abstract Nozzle hole diameter of 3D printer (3DP) can be varied to obtain required product quality as well as to reduce manufacturing times. The use of larger diameter may accelerate manufacturing times of products, yet the product quality, including the mechanical properties, still needs to be investigated profoundly. The purpose of this work is to investigate experimentally the effect of nozzle hole diameter of 3DP to the surface quality, accuracy, and the strength of the product. The specimens were manufactured by fused deposition modelling (FDM) 3D printing using polylactic acid (PLA) as the filaments.Bed temperature, extruder temperature and printing speed were set to be 60∘C, 200∘C and 80 mm/s respectively. The thickness of each layer was set at the ratio of 20% to the nozzle hole diameter. Infill pattern was determined by using line type of 100%. Nozzle hole diameter of 0.3, 0.4, 0.5 and 0.6mmwas compared in thiswork. The results show that bigger nozzle hole diameter enhanced the density and tensile strength of the products thought it was not linearly correlation.

Effect of Nozzle Hole Number on Diesel Engine Using Diesel and Biodiesel Blends

In this work the experiment was carried out to investigate the performance, combustion and emissions by changing the number of nozzle holes of the injector such as 3 hole, 4 hole and 5 hole by maintaining the hole diameter as 0.25mm. The experiments are executed on Kirloskar 4-stroke computerized single cylinder air cooled and electrical dynamometer coupled DI diesel engine with diesel, Rubber seed methyl ester and B20 Blend as fuels at 1500 rpm, with the injection timing of 23.4°BTDC with an injection pressure of 240 bar maintained constant throughout the experiment. It is found that 4 hole nozzle gives higher brake thermal efficiency, lower specific fuel consumption, CO, HC, for Diesel, Biodiesel and B20 Blend compared with other two nozzle holes. However the NOX got increased which is more for all the tested fuels by varying a number of nozzle hole diameter.

Analysis and application of cleaning tool structure in negative pressure reverse circulating wellbore

Sediments frequently appear at the bottom of oil and gas wells in the bottom of carbonate rocks during completion or production, seriously affecting the productivity. In order to solve the wellbore cleaning problem, this article applies the Bernoulli equation theory method, the finite element method based on the standard turbulence model and the laboratory test to verify a kind of negative pressure wellbore cleaning tool which can establish local reverse circulation under the action of high-pressure water jet and salvage the bottom debris. Through the numerical analysis of the cleaning tool structure, it is found that the wall face diameter is at least two times of the nozzle hole diameter to effectively play the cleaning tool performance. If the total area of nozzle outlet is 48π mm2, the cleaning tool fishing capacity of six nozzle structures is improved the most. The analysis of the adaptability of the cleaning tool shows that the cleaning tool with an outer diameter of 104 mm is most suitable for the casing shaft with an inner diameter of 127.3 mm. The cleaning tool was applied to the field operation and successfully cleaned the wellbore, effectively increasing the wellbore productivity.

Analysis of the Nozzle Hole Diameter Effect to Common Rail Diesel Engine Characteristics using a Calculated Model of an Internal Combustion Engine

Analysis of the Nozzle Hole Diameter Effect to Common Rail Diesel Engine Characteristics using a Calculated Model of an Internal Combustion Engine

Water purification experiment by applying flashing method with a rotating nozzle

Abstract The flashing process is a way of exposing water in a low-pressure environment by spraying it at high pressure so that the water converts into fine particles. This process is carried out to speed up the evaporation process of water. The evaporation process carried out on freshwater aims to separate the minerals and solids dissolved in water to increase its purity. In this study, the flashing process was carried out through a rotating nozzle that was proven to increase the rate of pure water production. The flashing process experiment is carried out following an experimental design based on the non-dimensional analysis of Buckingham's pi. The rate of pure water production () as the output variable in the flashing process is affected by the nozzle rotational speed (n), nozzle hole diameter (d), feedwater pressure (Pw), vacuum pressure (Pv) and feedwater temperature (T). The feedwater temperature itself can influence the behavior of the feedwater flow in the nozzle, in this case, is density (ρ) and viscosity (μ). Based on these variables, the non-dimensional analysis of Buckingham pi has produced four dimensionless numbers. The generated empirical equations from the flashing process experiments are in the form of quadratic equations. The empirical equation applies to feedwater pressure of 7.6 bar-g, the vacuum pressure of 0.4–0.6 bar-a and nozzle rotational speed of 0–134 rpm. The optimum condensation rate in the flashing experiment was successfully obtained, especially at the nozzle rotation of 27 rpm in all vacuum pressures tested. This success is inseparable from the use of mist-nozzles that convert the feedwater flow into the mist.

Correlation analysis upon the influential factors related to the dynamic response characteristics of pressure amplification piston in the fuel system for a low-speed diesel engine

Response characteristics are the key index to measure the performance of diesel engine fuel system. In this study, a simulation model of double-valve controlled common rail fuel system for low-speed diesel engine was presented. The accuracy of the model was fully validated by comparing calculation results with experimental data. Since the motion of pressure amplification piston (PAP) is highly correlated to fuel injection performance, the dynamic response of PAP was investigated. To determine the key factors influencing PAP dynamic response characteristics, a correlation analysis upon the structural parameters influencing opening response time (ORT) and closing response time (CRT) of PAP was performed based on the validated model. The results show that the change of working condition has a great effect on the opening process of PAP, but has little on closing process. Among all the isolated factors, the diameters of fuel plunger, high-pressure fuel tube and nozzle hole are the crucial factors related to the ORT of PAP. The diameters of fuel plunger, hydraulic piston and high-pressure fuel tube influence the CRT of PAP significantly. Among all the quadratic factors, the effects of interactions between diameter of fuel plunger and diameter of high-pressure fuel tube and between diameter of fuel plunger and diameter of nozzle hole on the ORT of PAP could not be neglected. The interactions between diameter of fuel plunger and diameter of high-pressure fuel tube and the interaction between diameter of high-pressure fuel tube and diameter of nozzle hole make great contribution to the CRT of PAP.

Influence of nozzle hole diameter on combustion and emission characteristics of diesel engine under pilot injection mode

Present work was divided in two different parts. In first part, an experimental study was carried out to analyze the effect of dwell on diesel engine combustion and emission characteristics. Experimental data showed that shorter dwell results in improved specific fuel consumption (SFC) but with increased smoke emissions penalty. To overcome the disadvantage of higher smoke emissions associated with shorter dwell, an effort was made to reduce smoke emissions under pilot injection mode by changing nozzle hole diameter (NHD) while keeping rest of the injection parameters unchanged. In second part, this was done numerically by using commercial Converge 3-D computational fluid dynamics (CFD) tool. In addition to baseline NHD (0.120 mm), two other NHDs i.e. 0.08 mm and 0.160 mm were considered. Numerical results showed that for given injection parameters, lower NHD resulted in faster evaporation of injected fuel as well as greater homogeneity of the mixture prepared due to better air entrainment inside fuel spray and hence led to overall faster combustion process. This faster combustion process subsequently reduced the time available for spray interactions. Therefore, in spite of getting further shortening of dwell in case of 0.08 mm NHD compared to other two cases, soot emissions were reduced by 87.2% when NHD was reduced from 0.160 mm to 0.08 mm. However, nitric oxide (NO) emission was found to increase by around 43% when NHD was reduced from 0.160 mm to 0.08 mm.

MIXTURE FORMATION ANALYSIS OF POLYOXYMETHYLENETHER INJECTION

Polyoxymethylenether (OME) is a promising fuel for CO2 reduction and a prospective change in the transportation sector. To see the effects of different fuel properties on mass flow rate and mixture formation, OME 3, OME 4, and a mixture of OME 3 and OME 4 (called OME Mix) are compared to European standard diesel fuel. They are investigated for a passenger car and two different commercial vehicle injectors with different nozzle hole diameters at engine relevant conditions of 5 MPa ambient pressure and 873 K ambient temperature. Mass flow rate measurements and optical measurement techniques like Mie scattering and Schlieren imaging are applied feeding the spray model of Musculus and Kattke to investigate the mixture formation. Additionally, a hydraulic and a computational fluid dynamic simulation of the internal nozzle flow are conducted to derive the fuel influence on the needle motion. The results show a strong influence of OME on the mass flow rate development via the correlated needle motion for commercial vehicle nozzle sizes. Depending on the fuel properties, the mass flow rate of OME is retarded in comparison to diesel under equal boundary conditions. The fuel-dependent needle opening impresses different initial momentum fluxes onto the spray. This hydraulic difference cannot be compensated in the upstream flow whereas the stream outside the hole follows the classical momentum conservation. For passenger car nozzle sizes the differences in mass flow rate and needle motion between OME and diesel fuel are not that distinctive, which lead to less deviations of the initially momentum fluxes.

Characteristics of Flat-Wall Impinging Spray Flame and Its Heat Transfer under Diesel Engine-Like Condition: Effects of Injection Pressure, Nozzle Hole Diameter and Impingement Distance

<div class="section abstract"><div class="htmlview paragraph">Substantial amount of fuel energy input is lost by heat transfer through combustion chamber walls in the internal combustion engines. Thus, these heat losses account for reduced thermal efficiency, in that spray-wall impingement plays a crucial role in Direct Injection diesel engines. The objective of this study is to investigate the mechanism of the heat transfer from the spray/flame to the impinging wall under small diesel engine-like condition and how the spray characteristics are affected with regards to effect of injection pressure, nozzle hole diameter and impingement distance. The experiment results showed that injection pressure was predominant factor on spray-wall heat transfer.</div></div>

Effect of spray nozzle-hole diameter on performance of 1 kw PEM fuel cell with honeycomb candle humidifier

Level of humidification of feed gases has tremendous effect on the performance of the proton exchange membrane (PEM) fuel cell. The extent of humidification depends on the duration of exposure to water and effectiveness of water spray. Among various parameters that affect the humidification of reactant gases, the effect of spray nozzle-hole diameter is scarcely investigated. Hence in the present study, experiments are conducted to know the influence of pumping cycle and nozzle-hole on stack current, stack voltage, stack temperature and dew point of a 1 kW PEM Fuel cell. Studies are also conducted to examine the effect of nafion dispersion coated honeycomb candle humidifier on the performance of the fuel cell. Best performance of the fuel cell is obtained in 300 s pumping cycle, with 3 mm spraying nozzle diameter when honey comb candle without nafion coating.

Effects of direct water injection and injector configurations on performance and emission characteristics of a gasoline direct injection engine: A computational fluid dynamics analysis

In-cylinder water injection is a promising approach for reducing NOx and soot emissions from internal combustion engines. It allows one to use a higher compression ratio by reducing engine knock; hence, higher fuel economy and power output can be achieved. However, water injection can also affect engine combustion and emission characteristics if water injection and injector parameters are not properly set. Majority of the previous studies on the water injection are done through experiments. Therefore, subtle aspects of water injection such as in-cylinder interaction of water sprays, spatial distribution of water vapor, and effect on flame propagation are not clearly understood and rarely reported in literature due to experimental limitations. Thus, in the present article, a computational fluid dynamics investigation is carried out to analyze the effects of direct water injection under various injector configurations on water evaporation, combustion, performance, and emission characteristics of a gasoline direct injection engine. The emphasis is given to analyze in-cylinder water spray interactions, flame propagation, water spray droplet size distribution, and water vapor spatial distribution inside the engine cylinder. For the study, the water-to-fuel ratio is varied from 0 to 1. Various water injector configurations using nozzle hole diameters of 0.14, 0.179, and 0.205 mm, along with nozzle holes of 4, 5, 6, and 7, are considered for comparison in addition to the case of no_water. Computational fluid dynamics models used in this study are validated with the available data in literature. From the results, it is found that the emission and performance characteristics of the engine are highly dependent on water evaporation characteristics. Also, the water-to-fuel ratio of 0.6 with 6 number of nozzle holes and the nozzle diameter of 0.14 mm results in the highest indicated mean effective pressure and the lowest NOx, soot, and CO emissions compared to other cases considered.

Effect of split injection ratio on combustion process of diesel spray into two-dimensional piston cavity

The purpose of this paper is to further understand the effect of split injection ratio on the diesel impinging spray combustion characteristics. Diesel combustion formed in the two dimensional piston cavity was studied in a high ambient pressure and high ambient temperature chamber. The injection pressure was 160 MPa and the diameter of single nozzle hole was 0.111 mm. Three split injection ratios were used: 25:75, 50:50 and 75:25. The KL factor and temperature distributions of the three injection strategies were analyzed and discussed. On this basis, the influence of the split injection ratio on the integrated KL factor and the flame temperature is discussed. The experimental results show that extending the splitting interval and decreasing the 2nd/1st ratio are beneficial to avoid the “catch-up” effect and reduce soot. In the absence of a “catch-up” effect, the domain process of soot formation and oxidation zones can be divided into six phases. However, the split injection influence on the flame is completed simultaneously. Due to the pre-injection, ignition is easier during the main injection. The relationship between the spatial KL factor and temperature is also discussed.

Effect of Fuel Injector Nozzle Hole Diameter on Emissions of CAT 3401 Diesel Engine Using CONVERGETM CFD

Variation of fuel injector nozzle hole is on engine emission and performance is evaluated in present article. Simulation is carried out on caterpillar 3401 diesel engine is using CONVERGE CFD code. A 60° sector model with SAGE combustion model was considered to examine the four different nozzle hole diameters (0.230mm, 0.240mm, 0.250mm, 0.259mm and 0.270mm) and their effect on the engine performance, emissions and spray characteristics. The combustion results showed that nozzle hole diameter of 0.230mm contributed for maximum in-cylinder pressure and temperature due to enhancement in spray cone angle, atomization, and efficient air-fuel mixture. HC, CO, and soot Emissions were found to be decreased with the decrease in nozzle hole diameter, however, due to enhanced atomization and the overall increase in cylinder gas temperature, the NOx emissions were observed to increase for nozzle holes with smaller diameters. Droplet radius for 0.250mm, 0.259mm and 270 mm is found to be larger to the formation of lower jet velocities. Thus nozzle holes with smaller diameter tend to reduce the emissions with a penalty in NOx emission.

Impact of increased injector nozzle hole diameters on engine performance, exhaust particle distribution and methane and formaldehyde emissions during dimethyl ether operation

E-Fuels can play a significant role in decarbonizing the transport sector. Among the potential E-fuels, dimethyl ether is a promising candidate for the combustion in compression ignition engines. Together with methanol, it can be produced from synthesis gas in a combined single-step process. However, due to the low volumetric heating value of dimethyl ether, the fuel injection system has to be modified to realize higher fuel flow rates. In this study, two injectors with increased nozzle hole diameters have been investigated, and their impact on engine performance, particle number distribution and formaldehyde as well as methane emissions was assessed. It was found that with dimethyl ether as fuel, the indicated efficiency at high load could be increased by over 1% compared to operation with conventional diesel fuel. The main reason for this is lower wall heat loss. Furthermore, almost no particle emission was found during dimethyl ether operation with the smaller nozzle. With the larger nozzle hole diameter, increased particle concentrations were measured at high loads. But these were still much lower compared to the corresponding diesel fuel combustion. Regarding formaldehyde and methane, higher emissions were found for the dimethyl ether combustion compared to diesel fuel combustion. It is assumed that this is due to the increased formaldehyde and methane production of dimethyl ether during high temperature pyrolysis and oxidation. The increased hydrocarbon emissions could have been caused by fuel dripping from the nozzle after the end of the injection event.