Injection Hole Diameter Research Articles

Design of water nozzle shape and structure optimization for eccentric injection mandrel in water injection wells

AbstractInjection mandrel is one of the key components to control the water injection rate of each layer in the layered injection process in the oilfield. The imbalance between the layers can be changed by an optimized injection mandrel to control the appropriate injection rate. This study introduces an approach to optimize water injection in oilfields, focusing on a new eccentric injection mandrel with adjustable flat nozzles. Firstly, computational fluid dynamics (CFD) simulations were carried out using FLUENT software to model and analyze the flow characteristics of the injection mandrel. The simulation results were validated through experimental comparisons, demonstrating excellent consistency. Secondly, the nozzle shapes were identified and optimized. The semicircle nozzle demonstrating superior regulation performance due to its smallest differential pressure and a robust linear relationship between flow rate and opening degree. Finally, orthogonal tests are designed for three influencing factors of the eccentric injection mandrel: number of injection holes, injection hole diameter, and nozzle shape. The simulation results show that the number of injection holes is 36, the diameter of injection holes is 3.2 mm, and the eccentric injection mandrel has relatively better performance. After optimization, the differential pressure between the inlet and outlet is reduced by 57.14%, and the average shear stress on the fluid is reduced by 3.88%. This innovative methodology, employing CFD simulations and orthogonal tests, offers precise water injection rate control, reducing water wastage, and optimizing energy consumption in water injection systems.

Effect of hydrogen injection hole diameter on the burning condition of a lifted flame in a hydrogen burner

Effect of hydrogen injection hole diameter on the burning condition of a lifted flame in a hydrogen burner

Fuel Consumption Rate Optimization Analysis of Dual-fuel Marine Diesel Engines Based on Orthogonal Design

To investigate the influence of diesel engine operating matching parameters on the comprehensive fuel consumption rate of butanol-diesel dual-fuel engines, a high-pressure combustion chamber cycle model of a 4190ZLC-2 marine medium-speed diesel engine was established using AVL-FIRE simulation software. After establishing the optimum blending ratio of butanol, the fuel system parameters were optimized using a one-time regression orthogonal experimental design method, and a mathematical model for fuel consumption rate prediction was constructed to find the combination of parameters with the lowest fuel consumption rate as the target. The study shows that inlet pressure has the greatest influence on the fuel consumption rate, followed by EGR and inlet air temperature. The lowest fuel consumption rate was achieved by combining the following parameters: (butanol blending ratio of 20%, EGR rate 0, inlet pressure 0.233 MPa, inlet temperature 325.15 K, Injection advance angle 22.6 °CA, the diameter of oil injection hole (0.26 mm); after optimization, the fuel consumption rate was reduced by 9.96% compared to the original machine.

Influences of injector geometry parameters on fuel injection characteristics and parameters of a diesel engine

Internal combustion engines (ICEs), especially diesel engines, continue to play a huge role in the development of the global economy. The research trends to improve combustion is still the main research direction in recent years with the help of 3D simulation tools. In this study, a 3D-model of a four-stroke, single-cylinder diesel engine was built using AVL Fire software to evaluate the influence of injector geometry parameters on engine characteristics. The results have shown that, with the injection pressure reaching 3000 (bar), and the turbocharger pressure maintained at 0.15 (MPa), the engine achieves the maximum power and the minimum brake fuel consumption when the angle between the axis of the nozzle hole and the axis of the fuel injection nozzle is 150 degrees. However, at this angle value, the soot emission value is the lowest but the nitrogen oxides (NOx) value is close to reaching the maximum. Hydrocarbon (HC) and carbon monoxide (CO) emissions are the lowest value at 155 degrees of the angle between the axis of the spray hole and the axis of the fuel injection nozzle. Besides, the study also evaluated the engine's parameters when changing the injector hole diameter. With an injection hole diameter of 0.24 (mm), the maximum engine power increased by 5.3%, and the brake-specific fuel consumption decreased by 7.2% compared to other values of injection hole diameter. However, the engine emissions are not the best values in this case.

Effect of Intake Conditions and Nozzle Geometry on Spray Characteristics of Group-Hole Nozzle

The group-hole nozzle concept is proposed to meet the requirement of nozzle hole minimization and reduce the negative impact of poor spatial spray distributions. However, there are limited researches on the effects of intake conditions and nozzle geometry on spray characteristics of the group-hole nozzle. Therefore, in this study, an accurate spray model coupled with the internal cavitating flow was established and computational fluid dynamics (CFD) simulations were done to study the effects of intake conditions and nozzle geometry on spray characteristics of the group-hole nozzle. Experimental data obtained using high-speed digital camera on the high-pressure common rail injection system was used to validate the numerical model. Effects of intake conditions (injection pressure and temperature) and nozzle geometry (orifice entrance curvature radius and nozzle length) on the flow and spray characteristics of the group-hole nozzle were studied numerically. The differences in Sauter mean diameter (SMD), penetration length and fuel evaporation mass between single-hole nozzle and group-hole nozzle under different nozzle geometry were also discussed. It was found that the atomization performance of the group-hole nozzle was better than that of the single-hole nozzle under same intake conditions, and the atomization effect of the short nozzle was better than that of the long nozzle. With increase in the orifice entrance curvature radius, the average velocity and turbulent kinetic energy of the fuel increased, which was conducive to improving the injection rate and flow coefficient of the nozzle. Meanwhile, the penetration length and SMD value rose, while evaporation mass dropped. When the ratio of the orifice entrance curvature radius (R) to the diameter of injection hole (D) was 0.12, the spray characteristics reached a constant state due to elimination of cavitation. Conclusions were made based on these. This study is expected to be a guide for the design of the group-hole nozzle.

Numerical study of combustion and cooling performance of a gaseous oxygen and gaseous methane rocket combustor with the needle-bolt injector

The needle-bolt injector is a convenient method for adjusting the propellant combustion and has attracted a great deal of attention in recent years. However, the effects of injector parameters on the flow and temperature fields in the combustion chamber are rarely investigated. In this study, a new computational fluid dynamic rocket combustor model based on needle-bolt injector is established to study the combustion performance of the gaseous oxygen and gaseous methane (GOx/GCH4) rocket. Three key parameters of needle-bolt injector including the radial fuel injection hole diameter Df, the needle valve diameter Dn and the length of needle into the combustion chamber L are studied. In addition, a special coolant hole for liquid coolant cooling is proposed to reduce the high temperature gathered in thrust chamber. Compared with the chamber wall temperature of 1807 K without cooling, the wall temperature can be reduced to 1467 K after introducing 15% of water coolant. However, with a further increase in coolant ratio from 25% to 30%, the cooling effect is not obvious. The present numerical study can provide important guidance for studying combustion characteristics and cooling performance of rocket combustor with the needle-bolt injector.

The Effect of Injector on Diesel Engine Characteristics Used Common-Rail System

Nowadays, Diesel engines are so popular, especially in the field of transportation and marine. It has also improved over the generations, from a mechanical control system to an electronic control system. The Common-rail fuel system is considered the best development system on Diesel engines today. The injection pressure is very high, however, to increase power, reduce consumption and emission, further improvement is necessary. In this research, AVL - FIRE software was used to studying the effect of injectors to combustion chamber, the injection hole diameter related to: power, torque as well as exhaust gas on Diesel engine (Toyota Hiace 2KD-FTV). The results show that with d=0.16mm, the best power, low fuel consumption but high emissions, with d=0.2mm, the lowest emission. The results of this research improve fuel injectors and Diesel engine performance.

Effects of pulsed endwall air injection on corner separation and vortical flow of a compressor cascade

ABSTRACT Air injection is an effective method to eliminate flow separation and improve blade loading in compressors. In existing studies on unsteady air injection, achieving a better control effect than steady injection with lower injection consumption is a major difficulty and challenge. In this work, pulsed endwall air injection (PEAI) was carried out numerically in a highly loaded compressor cascade under different injection frequencies and injection amplitudes. The mechanism through which PEAI influences corner separation and vortical flow, especially the effect of initial injection phase on the flow field of compressor cascade, was revealed. The results showed that PEAI effectively suppressed the corner separation with lower injection mass flow rate compared with steady endwall air injection (SEAI). The time-averaged overall loss coefficient and endwall loss coefficient were reduced by 10.5% and 28.7%, respectively, under the optimal PEAI scheme. Higher injection amplitude exhibited a more effectively controlled range in the suction corner, which led to a decrease in corner separation and deterioration of the mid-span flow field. The interaction between trailing edge separation and low-momentum fluid at mid-span led to the formation of an injection vortex. When conducting PEAI, the effect of inertia was observed for flow in the injection hole, which was derived from the interactions between injection fluid at different velocities and will increase with the improvement of injection frequency. The effects of injection location and diameter of the injection hole were also investigated. The injection location of PEAI affected the flow field by changing the effect region of the injection and low-momentum fluid near the endwall. The injection hole diameter had a significant impact on the intensity of the passage vortex and mid-span flow field.

Effects of Various Injection Holes with/without Opening Angles of Film Cooling on Blades of Gas Turbine: A CFD Approach

The combustor exit temperature is steadily rising to improve the overall efficiency of the gas turbine. As a result, film cooling, the most important and necessary cooling technology, must be developed further to satisfy this demanding requirement. The film cooling performance on the NACA 0012 gas turbine blade is numerically evaluated in this research using 6 different injection holes with and without opening angles. The Computational Fluid Dynamics (CFD) software Ansys Fluent v16 is used to conduct 2-dimensional Reynolds-Averaged Navier-Stokes (RANS) flow and heat transfer analyses. The flow is assumed to be steady, turbulent, and incompressible. To obtain solutions, the incompressible RANS equations are solved using the finite-volume technique. The simulation results indicate that the SST k-ω turbulence model is appropriate for simulating flow characteristics and evaluating film cooling efficiency over the blade. Furthermore, the opening angle has a beneficial impact on the upper blade surface's cooling performance. The injection hole with an opening angle of 15º and a height of D (injection hole diameter) achieves the maximum value of cooling efficiency. The coolant injected from the hole provides greater cooling coverage for the entire blade in this configuration, increasing cooling effectiveness.
 HIGHLIGHTS
 
 The influence of various geometries of injection holes on the effectiveness of film cooling was investigated
 The low opening angle has a greater impact on film cooling than the other opening angles
 The injection hole with an opening angle eliminates the recirculation region after the coolant exits
 
 GRAPHICAL ABSTRACT

Measurement and analysis of injection characteristics among each nozzle hole within a heavy-duty diesel engine

The mass flow rate from each injector nozzle hole of a diesel engine influences the distribution, atomization, and combustion of fuel in the chamber. Thus affecting the power, the fuel economy, and the emission quality of the diesel engine. A spray momentum flux test bench was built and used to measure the injection rate from each nozzle hole of a multi-hole nozzle in this study. Selected force sensors used for data acquisition were one of the integral parts of the set-up. The influence of the force sensors’ installed position (location in the set-up) on measured results, were analyzed and the optimum position that ensures independence of the results, determined. Additionally, the effects of injection pressure, injection pulse width and injection hole diameter on the injection characteristics were also investigated. Furthermore, in this research, the reliability and robustness of Strain sensor and Piezoelectric sensors were analyzed with regards to their response. The analysis showed that, strain sensors have weak dynamic response characteristic compared to piezoelectric sensors also, the measured result obtained from strain sensors fluctuated greatly. Piezoelectric force sensor gave a more reliable and stable measurement, comparatively. The accuracy of the results were affected by the installation position of the sensors. A distance of 16 mm (between nozzle hole exit and sensor surface) was determined to be adequate for the acquisition of reliable experimental data. As the injection pressure gets higher (during injection), the rate of mass flow increased, the average cycle-to-cycle variation coefficient and nozzle-to-nozzle variability coefficient of injection quantity decreased. Hence, improving the consistency of each cycle and the uniformity of each hole. In addition, increasing the injection pulse width decreased the average cycle-to-cycle variation coefficient. Also, nozzle-to-nozzle variability coefficient had minimal or no influence with regards to injection pressure. At 80 MPa, the uniformity of injection from the multi-hole nozzle improved significantly. In summary, the larger the hole diameters, the higher the maximum value of mass flow rate and the fuel injection quantity.

Analysis of the Ignition Behavior Based on Similarity Factor Method

The chemical kinetics mechanism is an important factor to accurately predict the combustion characteristics of constant-volume bomb (CVB). In this study, an n-heptane oxidation mechanism constructed by Wang et al. is introduced to study the correlation of the ignition behaviors with the mechanism constructed by Chang et al. The effects of the similarity factor method in the analysis of ignition behaviors of fuel in CVB were repeatedly verified by changing the important spraying parameters: injection pressure and hole diameter. Through further verification, it was found that the combustion process was controlled at approximately 850 K and stoichiometric ratio mixture of fuel/air in CVB, which corresponds to the negative temperature coefficient region at stoichiometric ratio mixture in shock tube (ST). The mechanism verified by the experiment under the condition in ST can reflect the chemical ignition in CVB. In addition, the similarity factor method was less dependent on the chemical reaction mechanism and boundary conditions.

A GMDH-type neural network model for predicting the effect of sister hole parameters on the film cooling effectiveness over a turbine blade

In this paper, a three-dimensional numerical analysis was employed to investigate the flow and thermal fields over a leading edge of AGTB-B1 high-pressure turbine blade. The effect of different parameters on the film cooling was studied. The computational methodology includes the use of a structured, non-uniform hexahedral grid consisting of the main flow channel, the coolant delivery tube and the feeding plenum. The SIMPLEC algorithm was implemented for pressure–velocity coupling. Computations were carried out for the following range of film cooling parameters: lateral position of sister holes 3, 3.5 and 4.75 mm; lateral angle of sister holes of − 8°, 0° and 8°; blowing ratio of 0.7, 1.1 and 1.5; and diameter of injection hole of 2, 2.5 and 3. Adiabatic effectiveness was used as a criterion to judge the performance of film cooling. The results show a good agreement compared with previous experimental and numerical data. Finally, the GMDH-type neural network was successfully employed for modeling and presenting a correlation for film cooling effectiveness as a function of effective parameters.

Study of a hybrid pneumatic-combustion engine under steady-state and transient conditions for transport application

In this study, a new form of hybrid pneumatic combustion engine based on compressed air injection boosting is proposed. The hybrid pneumatic combustion engine regenerates the wasted energy during engine brake to improve the engine performance achieving better fuel economy. The mathematic model of the hybrid pneumatic combustion engine including a supercharged engine and the compressed air tank has been established. The steady-state and transient performance of the engine are analysed. Results show that the air injection boosting system can effectively improve the steady-state performance. Under the speed of 1900 r/min and 100% load, the engine torque and power can be increased from 1039 N m, 206.9 kW to 1057 N m, 210 kW by adopting air injection boosting with the injection pressure of 0.5 MPa. Effects of air injection parameters are also studied, showing that better performance can be achieved under higher air tank pressure and larger injection hole diameter. In addition, a transient analysis is completed under the speed of 1100 r/min. The result shows that when air injection boosting is used, the responding time of the engine to an instant load increase can be potentially reduced from 5.5 to 3.5 s under the injection pressure and duration of 0.5 MPa and 3 s. Meanwhile, the tank pressure has limited influence on the transient performance of the engine.

Influence of clogging of a T-shaped desulfurization lance on the flow field in a hot metal ladle

Lance injected desulphurization become ineffective when injection ports become obstructed. In this work, the difference of the flow fields between single and double hole injection was investigated by numerical simulations. When one of the openings in a T-shaped injection lance is blocked, a dead zone occurs in the ladle over approximately 1/4th of the volume, and there is not an active flow field on the surface of clogging side. To decrease clogging, industrial experiments examining different diameter lances were carried out. The results showed that clogging can be reduced by increasing the injection pressure and optimizing the injection hole diameter to be approximately 10 times the particle size of desulphurizer.

Studies on effusion cooling: Impact of geometric parameters on cooling effectiveness and coolant consumption

This study is focused on the impact of certain important geometric parameters on cooling effectiveness and coolant consumption for effusion cooling of aircraft combustor liner. The three dimensional turbulent flow field in a domain representing the combustor with several rows of effusion coolant injection is considered for the analysis. The geometric parameters considered are: angle of injection of the coolant, axial and transverse pitch of the injection holes, hole spacing and hole diameter. Also, based on the analysis of the temperature field within the chamber, a novel concept of ‘variable hole diameter’ has been introduced to reduce coolant consumption. A symmetric 3D computational model including the combustion chamber, coolant chamber and the effusion plate was used for the study. Conjugate heat transfer was modeled between the effusion-cooled wall and the two chambers. A detailed mass flow rate analysis has been performed for the various cases in order to study the impact of parameters on coolant consumption. The proposed approach of using an effusion plate with variable hole diameters is found to be effective in reducing the net coolant consumption significantly while maintaining a given level of cooling effectiveness.

Influence of injection pipe characteristics on pulse-jet cleaning uniformity in a pleated cartridge filter

Pleated cartridge filters are widely used to remove dust in industrial processes. However, pulse-jet cleaning is not uniform between filter cartridges. This is due to uneven transient pressure below the injection holes leading to the increase of operating resistance and decline in the cleaning cycle, both of which are detrimental to pleated cartridge filter operation. Therefore, the injection pipe plays an important role in pulse-jet cleaning. In order to provide guidance for injection pipe design, a pulse-jet cleaning experimental system was designed. Experiments involved a constant total filtration area under four working conditions; the effects of the injection hole diameter, the number of injection holes, the jet distance, and the tank pressure on pulse-jet cleaning were studied by testing the static pressure on the inner wall of the cartridge. This also allowed optimization of the jet distance, orifice ratio, injection hole diameter, and internal cartridge volume. The results showed that 1) the transient pressure below the injection holes increased gradually along the airflow direction of the injection pipe, and 2) the peak positive pressures on the corresponding cartridge inner surfaces also increased. Both of these pressure values increased with increasing tank pressure. Peak positive pressure on the inner wall of the cartridges first increased, and then decreased with increasing jet distance. The injection hole diameter and the optimum jet distance can be described by mathematical models developed from this study. The optimum jet distance decreased with increasing injection hole diameter. The optimum orifice ratio range was 0.6–0.8 under the optimum jet distance, adoption of which improved the pulse-jet intensity significantly. Injection hole optimization resulted in gradually decreasing injection hole diameter along the airflow direction of the injection pipe and increased the pulse-jet uniformity by a factor of 5–8. The internal volume of the cartridge influenced pulse jet cleaning under constant filtration area.

Investigation on the effect of geometrical parameters on the performance of a venturi type bubble generator

The venturi type bubble generator adopted in the fission gas removal system for the liquid-fuel thorium molten salt reactor plays a crucial role in strengthening the mass transfer rate. Aiming at clarifying how these three main geometrical parameters, including the injection hole diameter, injection hole number, and divergent angle, influence the bubble size distributions, an experimental study is carried out. The bubble size distribution is extracted from the images captured by the high speed visualization. Post processing algorithm is developed to detect the bubble edges and compute their Sauter mean diameters for each flow condition. By changing the value of each geometrical parameter, the variation of the bubble size distribution is obtained and discussed. It is shown that the injection hole diameter and number basically have little effect on the bubble size distribution while the divergent angle is proved to be sensitive. Finally, the reasons that account for the bubble size variation with three geometrical parameters are explained by the bubble turbulence breakup theory.

A CFD simulation study of air-lift artificial upwelling based on Qiandao Lake experiment

The application of artificial upwelling technology could increase the primary marine productivity by bringing nutrient-rich subsurface water to surface. Although the artificial upwelling has been extensively studied, few numerical simulation studies on artificial upwelling device parameters, such as nozzle type, injection depth and injection hole diameter, have been conducted. This paper establishes a computational fluid dynamics (CFD) model to theoretically analyze how the upwelling efficiency were influenced by injection nozzle type, diameter of injection hole and injection depth. The comparison between the simulation results and the corresponding experimental data obtained in Qiandao Lake experiments firstly proves the accuracy of the predictions of CFD model in terms of upwelling efficiency via changing the parameters of the artificial upwelling device; secondly, it also indicates that the circular type of an air injection nozzle installed in deeper water depth with larger injection holes brings more deep water to the surface. It is believed that this study may shed some light on the improved design of an artificial air-lift upwelling device.

Numerical study on the optimal design of injection-hole geometries of a twin rotary compressor in a liquid injection heat pump

In a liquid injection heat pump, it is very essential to control the compressor discharge temperature without wet-compression problems at extreme outdoor conditions. The objective of this study was to optimize the injection-hole geometries of a liquid injection heat pump in order to prevent the risk of wet-compression while reducing compressor discharge temperature at overload cooling conditions. In this study, a simulation model for predicting the performance of a liquid injection heat pump was developed and validated. The optimum injection-hole geometries were determined to obtain the maximum multiplication ratio, which led to a lower instant injection mass flow rate in terms of R- and θ-directional positions. In addition, the injection-hole diameter was minimized to prevent wet-compression while obtaining the target injection mass flow rate. The discharge temperature of the optimized compressor was decreased by 9.2°C over the baseline compressor while maintaining the same risk for wet-compression at the overload cooling test condition.

Improving film cooling from compound angle holes by adding secondary holes branched out from the main holes

A numerical simulation is used to investigate the effect of adding secondary hole branched out from a compound angle injection hole. The use of secondary holes with compound angle film cooling is considered as a novel concept of compound angle film cooling. The used orientation angle is 30°. The diameter of the secondary hole is half of the main diameter (compound angle injection hole diameter). The studied cases are considered at blowing ratios of 0.5, 0.75, 1.0, 1.5, 2.0, and 2.5. The study was carried out using the realizable k-e model. The presence of the secondary hole improves the film cooling at all studied blowing ratios except at M = 0.5 due to the weakness of the coolant flow through the main hole. The flow through the secondary hole tries to damp the vortex coming out from the main hole. The optimum blowing ratio is at M = 0.75–1.0. The enhancement in the overall film cooling effectiveness at M = 1 is 0.12 as compared to the compound angle injection hole case by about 83%.