Browse Topic: Nozzles

Items (1,356)
Oxygenated substances are a promising approach in the field of alternative fuels. A current example of such a fuel are Polyoxymethylene Dimethyl Ethers (OME). With their physical and chemical properties, alternative fuels like OME pose new challenges for diesel engine injection systems. As the heating value is low compared to conventional Diesel fuel, measures must be taken to increase the amount of fuel injected. Possible solutions include increasing the nozzle hole diameter, the injection pressure, and the number of nozzle holes. All mentioned adaptions have an influence on the mixture formation and make it necessary to examine the injection process in detail also with regard to phenomena such as cavitation. In this study, three passenger car Diesel injector nozzles are compared, two of which are adapted in terms of nozzle hole diameter (increase by 20%) and number of nozzle holes (increase from 8 to 12) in order to increase the mass flow rate of fuel to the required elevated level
Riess, SebastianFuchs, ThorstenStrauß, LukasGünthner, MichaelWensing, Michael
The objective of this paper is to identify the optimum supersonic Mach number for expansion–deflection dual-bell nozzle. The numerical analysis is carried for expansion–deflection dual-bell nozzle (EDDBN) with different free stream conditions. Numerical study observes that the transition pressure ratio and Mach contours are studied through inside and outside of the nozzle. The results proved that increasing the Mach number leads to decrease in the static pressure as well as reduce the performance of EDDBN nozzle. The analysis was carried out for four different Mach number, out of which Mach number 1.2 provides the optimum results. In the present study, the influence of Mach number behavior affects the pressure and Mach configuration inside and outside of the EDDBN nozzle. This novel concept is used in supersonic vehicles for higher performances. Also, it provides a way to improve the existing nozzle design configuration
Balaji, K.Kalekar, YashdeepNaik, AtharvaWalave, GurudasCharapalle, Samruddhi
The high-pressure common rail fuel injection system for diesel engines is one of the core technologies that need to be addressed in the automobile industry. The control of the internal flow in multi-hole injector nozzles is the key to achieve accurate control of the fuel injection and spray process. There are various types of research on cavitation phenomena currently conducted on various types of test benches, but there is no conclusive discussion. Therefore, it is to summarize these studies in order to identify the highlights of existing studies and point out their shortcomings. This article compares and analyzes the developing patterns of cavitation phenomena on four test benches through literature review and has obtained rich research data on these four types of nozzles, but they still have their own shortcomings at the same time, even with numerical simulation. Based on this, the article has conducted a detailed and critical discussion on the current research situation and
Cao, TianyiJin, JianjiaoQu, Yu Pu
This study aims to design a supersonic ejector, referred to as a liquid spray gun, with a simple operating procedure for producing an aerosol spray with adjustable droplet size distributions. A CFD model was developed to determine the influence of nozzle exit position and the primary air pressure on the supersonic patterns formed within the ejectors, providing a valuable insight into their internal physics. Based on the single-phase numerical results, at an air primary pressure of 2 bar, the flow may not reach a choking condition, possibly resulting in unstable ejector operation. However, at pressures exceeding 5 bar, the jet patterns emerging from the primary nozzle cause flow separation or the formation of vortex rings. This phenomenon leads to a flow configuration comparable to the diameter of the mixing tube, thereby reducing the available area for entrainment of suction flow. The suitable ejector was identified with a nozzle exit position of 13 mm and a primary pressure ranging
Nguyen, Quan Q.Phung, Duoc V.Nguyen, Kien T.Pham, Hoang Q.Pham, Thin V.Vu, Tuan N.Pham, Phuong X.Duong, Cuong Q.
This study explores the feasibility of using a sustainable lignin-based fuel, consisting of 44 % lignin, 50 % ethanol, and 6 % water, in conventional compression ignition (CI) marine engines. Through experimental evaluations on a modified small-bore CI engine, we identified the primary challenges associated with lignin-based fuel, including engine startup and shutdown issues due to solvent evaporation and lignin solidification inside the fuel system, and deposit formation on cylinder walls leading to piston ring seizure. To address these issues, we developed a fuel switching system transitioning from lignin-based fuel to cleaning fuel with 85 vol% of acetone, 10 vol% of water and 5 vol% of ignition improving additive, effectively preventing system clogs. Additionally, optimizing injection parameters, adopting a constant pressure delivery valve, and fine-tuning injection timing mitigated lignin deposit formation related to incomplete combustion or spray tip penetration to the cylinder
Terauchi, MotokiSimonsen, TorMortensen, SimonSchramm, JesperIvarsson, Anders
The geometry of high-pressure pump and injector nozzles crucially influences hydraulic behaviors (e.g., the start of injection, the pressure profiles developed in the high-pressure line, needle lift, and injection rates) in diesel engines. These factors, in turn, significantly impact fuel atomization, fuel–air mixing, combustion quality, and the formation of emissions. The main geometry parameters such as plunger diameter and the number and diameter of nozzles lead to the system complexity, requiring careful analysis, design, and calibration. In this study, a high-speed shadowgraph system and a high-resolution pressure recording system were developed to capture the start of injection, spray structure, and pressure profiles in the high-pressure line. Additionally, a model was developed using GT-Fuel package built within the GT-Suite of simulation tools to explore different plunger diameters and numbers and diameters of injector nozzles. These models were validated using the pressure
Nguyen, Quan Q.Vu, Manh D.Phung, Duoc V.Nguyen, Kien T.Vu*, Tuan N.Pham, Phuong X.
A need to develop a cooling method with high cooling performance like jet impingement is increased as high power of an inverter is required. Jet Impingement on the dimpled plate would increase thermal performance than that of flat plate. Many previous researchers have dealt with the multi jet impingement on flat plate and some results of the study on dimpled plate evaluate the effect on heat transfer coefficients on several limited cases, making it difficult to apply them to inverter designs. Therefore, in this paper, heat transfer performance, pressure drop, and robustness at micro-scale of jet impingement on the dimpled plate were investigated in detail and the correlations of each performance were proposed. Finally, the optimal design was presented. The cooling performance was influenced by the jet array and the effect of depth and width of the dimples. The former can be expressed in terms of the Reynolds number, the ratio of height to nozzle diameter(H/D), the ratio of pitch to
LEE, HyeseungYang, IlsukJeong, HojinPark, Minkyu
The passive pre-chamber (PC) is valued for its jet ignition (JI) and is suitable for wide use in the field of gasoline direct injection (GDI) for small passenger cars, which can improve the performance of lean combustion. However, the intake, exhaust, and ignition combustion stability of the engine at low speed is a shortcoming that has not been overcome. Changing the structural design to increase the fluidity of the main chamber (MC) and pre-chamber (PC) may reduce jet ignition performance, affecting engine dynamics. This investigation is based on non-uniformly nozzles distributed passive pre-chamber, which is adjusted according to the working medium exchange between PC and MC. The advantages and disadvantages of the ignition mode of PC and SI in the target engine speed range are compared through optical experiments on a small single-cylinder GDI engine. The results show that with the increase of λ from 1.0 to 1.6, the promotion effect of PCJI on dynamic performance gradually
Tang, YuanzhiLou, DimingFang, LiangFan, BenzhengWu, XijiangWang, ZhiyuZhang, YunhuaTan, PiqiangHu, Zhiyuan
The China Automotive Technology and Research Center (CATARC) has completed two new wind tunnels at its test centre in Tianjin, China: an aerodynamic/aeroacoustic wind tunnel (AAWT), and a climatic wind tunnel (CWT). The AAWT incorporates design features to provide both a very low fan power requirement and a very low background noise putting it amongst the quietest in the automotive world. These features are also combined with high flow quality, a full boundary layer control system with a 5-belt rolling road, an automated traversing system, and a complete acoustic measurement system including a 3-sided microphone array. The CWT, located in the same building as the AAWT, has a flexible nozzle to deliver 250 km/h with an 8.25 m2 nozzle, and 130 km/h with a 13.2 m2 nozzle. The temperature range of the CWT is -40 °C to +60 °C with a controlled humidity range of 5% to 95%. Additional integrated systems include a variable angle solar simulator array, and a rain and snow spray system. This
Waudby-Smith, PeterBender, TrevorSooriyakumaran, ChristopherZhang, YilunWang, HaiyangZhao, FengFan, GuangjunSun, JinhongLiu, Xuelong
Present work investigates the relationship between the combustion parameters of a well-known ECN heavy-duty nozzle called Spray D and marine-size nozzles. The study is carried out in OpenFOAM software within the framework of RANS turbulence modelling, using a flamelet based tabulation technique known as FGM to model the combustion. The large nozzles are tested in a constant volume chamber representative of marine engines, for which a CFD setup is validated against inert data in literature. The reacting results have been validated first with experimental data, initializing the domain with a highly reactive environment (23% oxygen) and engine-like swirl. Then, a less reactive initial condition was set up in the domain (15% oxygen) without swirl, to achieve a Spray D-like environment. The main goal is to study the variation of the combustion parameters Ignition Delay Time (IDT) and Lift-Off Length (LOL) as function of nozzle diameter, leading to a mathematical correlation to estimate the
Di Matteo, AndreaSomers, Bart
In this work, an investigation of the enthalpy effects on the thermochemical non-equilibrium in hypersonic nozzles is performed. Three different nozzles, with different geometries and stagnation enthalpy conditions are used in this study. The three cases, two of them with stagnation enthalpy conditions of 3.3 MJ/kg and 7.56 MJ/kg, use molecular nitrogen as the testing fluid and in the third case, corresponding to the higher enthalpy condition of 23.8 MJ/kg, the fluid is partially dissociated air composed by five neutral species (N2, O2, NO, N and O). A reliable numerical model, previously validated by the authors, using non-equilibrium Navier-Stokes-Fourier equations within a density-based algorithm is here employed in the OpenFOAM framework. After an estimation of the discretization uncertainties by using the Richardson extrapolation method and Roache’s Grid Convergence Index, the results are obtained by using a sufficient independent grid for each case. It was found that the nozzle
Teixeira, OdelmaPascoa, Jose
At present, the problem of global warming is becoming more and more serious, and the transformation of energy structure is very important. The rotary engine has the advantages of small size, high power-to-weight ratio, and high fuel adaptability, which makes it promising for application in the fields of new energy vehicle range extender and unmanned aerial vehicle. To this end, this paper proposes the idea of hydrogen/ammonia dual-fuel combination applied to rotary engine, using the experimentally verified three-dimensional simulation model of rotary engine, to study the process of hydrogen/ammonia rotary engine in-cylinder mixture formation under the direct-injection dilute combustion mode, and to analyze the impact of different dual-fuel injection strategies on the performance of rotary engine, and finds that delaying the moment of injection leads to the ammonia concentration in the middle and front of the combustion chamber; when the ammonia nozzle is located in the intake port, the
Chen, WeiYang, XuYu, ShiwuLiu, XuHe, WeibiaoZuo, Qingsong
Interest in the use of kerosene fuel in diesel engines has garnered researchers’ attention in the past few years due to its improve premixed combustion and its ability to decrease soot emission. The potential of using kerosene in the design stage of a diesel engine is thus a great motivator to study fuel spray development and to evaluate known fuel spray tip correlations and models with respect to their predictive capability with such a fuel. Therefore, the present paper proposes to investigate the spray development of a multi-hole solenoid injector fueled with kerosene under non-evaporative conditions. Moreover, the experimental results are used to evaluate how different phenomenological models proposed in the literature for diesel fuel are able to predict kerosene spray tip penetration. The experimental test rig is composed of a constant-volume pressurized vessel and a camera allowing to visualize the liquid phase using a backlight illumination technique. The influence of the
Billerot, Pierre-LouTétrault, PascalFleischmann, AntoineLemaire, RomainSeers, Patrice
The supercritical fluid combustion technology was regarded as an effective method to increase fuel gas mixing rate and performance. During the injection process, critical characteristics dominate the jet development to behave as different spray structure. Due to the limited researches about supercritical gasoline-like fuel injection characteristics, macroscopic and near-nozzle microscopic spray structures of supercritical n-heptane injected into atmosphere condition were observed and compared with the injection of cryogenic nitrogen in this work. A supercritical fuel injection device was designed able to heat the fuel temperature up to 773 K and maintain the fuel injection pressure stable at 4 MPa. Backlight illumination and schlieren imaging technologies were applied to capture the liquid and overall jet structure. The effect of initial fuel temperature on the spray structure was analyzed and some novel near-nozzle structures were also discussed. Results show that with the increase of
Liu, RuiHuang, LiNi, XinminJu, DehaoYi, RanMa, Yue
Hydrogen energy is a kind of secondary energy with an abundant source, wide application, green, and is low-carbon, which is important for building a clean, low-carbon, safe, and efficient energy system and achieving the goal of carbon peaking and being carbon neutral. In this paper, the effect of nozzle position, hydrogen injection timing, and ignition timing on the in-cylinder combustion characteristics is investigated separately with the 13E hydrogen engine as the simulation object. The test results show that when the nozzle position is set in the middle of the intake and exhaust tracts (L2 and L3), the peak in-cylinder pressure is slightly higher than that of L1, but when the nozzle position is L2, the cylinder pressure curve is the smoothest, the peak exothermic rate is the lowest, and the peak cylinder temperature is the lowest. When the ignition timing is consistent, with the delay of hydrogen injection timing, the peak in-cylinder pressure decreases and the peak phase remains
Tan, PiqiangTian, YuanLou, DimingZhang, YunhuaLiu, DengchengZhao, Keqin
Physical fluid properties and GDI injector deposits are known to impact the internal nozzle flow and external spray morphology. Furthermore, deposits can affect injector calibration and damage the delicate mixing and combustion processes. Despite this, there is a lack of experimental data demonstrating the discrete influence of fluid properties and how this influence evolves with the formation of injector deposits. This article aims to further the existing knowledge on the effect of fluid properties such as density, kinematic viscosity and surface tension, along with distillation on fuel spray characteristics and provide insight into how sprays change over the lifetime of GDI injectors due to fouling. In this investigation, four gasoline fuels with varying concentrations of ethanol and typical GDI additive, including one being representative of a renewable gasoline formulation, were used with clean and fouled multi-hole GDI fuel injectors. A low-pressure constant-volume chamber was
Gander, Alexde Sercey, GuillaumeCrua, Cyril
For further increase in thermal efficiency of heavy-duty diesel engines, flexible regulation of the heat release rate (HRR) profile combined with higher compression ratio could have more rooms to improve indicated thermal efficiency by overcoming various drawbacks relevant to higher compression ratio. A new ideal HRR profile, which starts as a kind of delta shape to fulfil the isobaric cycle from top-dead-center (TDC) and is followed by the significant increase in HRR to reach the maximum cylinder pressure in the retarded timing, was proposed. We call it as ‘High-heels’ HRR profile from its two-step-increase delta shape. To confirm the potential of the ideal HRR profile by utilizing a single- cylinder heavy-duty diesel engine, a variable fuel injection rate equipment, novel combustion chamber designs, and an offset orifices nozzle were investigated as the technologies for modifying HRR profile. The experimental results confirmed slight improvement in the thermal efficiency from the
Uchida, NoboruWatanabe, Kazumasa
In this study, the effect of injection pressure, impingement distance and angle, wall temperature on the macroscopic of wall impingement were investigated experimentally, predicted by using deep neural network in the MATLAB environment. With respect to obtaining data from experiments, input factors affecting impingement phenomena are trained, validated to develop model, which was applied to estimate output such as spray tip penetration and height. According to the results, the estimate parameters by coefficient of determination, root mean square error between 0.998 and 0.029. The ANN_GA model is found to be an effective tool to predict spray behaviors output with minimal experimentation
Pham, QuangkhaiChoi, ByungchulPark, Suhan
Pre-chamber jet ignition technologies have been garnering significant interest in the internal combustion engine field, given their potential to deliver shorter burn durations, increased combustion stability, and improved dilution tolerance. However, a clear understanding of the relationship between pre-chamber geometry, operating condition, jet formation, and engine performance in light-duty gasoline injection engines remains under-explored. Moreover, research specifically focusing on high dilution levels and passive pre-chambers with optical accessibility is notably scarce. This study serves to bridge these knowledge gaps by examining the influence of passive pre-chamber nozzle diameter and dilution level on jet formation and engine performance. Utilizing a modified constant-volume gasoline direct injection engine with an optically accessible piston, we tested three passive pre-chambers with nozzle diameters of 1.2, 1.4, and 1.6 mm, while nitrogen dilution varied from 0 to 20%. With
Lee, Dong EunIyer, ClaudiaWooldridge, StevenQiao, LiYi, Jianwen J.
Pre-chamber turbulent jet ignition (TJI) is a method of generating distributed ignition sites through multiple high-speed turbulent jets in order to achieve an enhanced burn rate in the engine cylinder when compared to conventional spark plug ignition. To study the gas-dynamic interactions between the two chambers in a gasoline engine, a three-dimensional numerical model was developed using the commercial CFD code CONVERGE. The geometry and parameters of the engine used were based on a modified turbocharged GM four-cylinder 2.0 L GDI gasoline engine. Pre-chambers with nozzle diameters of 0.75 mm and 1.5 mm were used to investigate the effect of pre-chamber geometry on pre-chamber charging, combustion, and jet formation. The local developments of gas temperature and velocity were captured by adaptive mesh refinement, while the turbulence was resolved with the k-epsilon model of the Reynolds averaged Navier–Stokes (RANS) equations. The combustion process was modeled with the extended
Yu, TianxiaoLee, Dong EunGore, Jay P.Qiao, Li
Considerable amounts of water accumulate in aircraft fuel tanks due to condensation of vapor during flight or directly during fueling with contaminated kerosene. This can result in a misreading of the fuel meters. In certain aircraft types, ice blocks resulting from the low temperatures at high altitude flights or in winter time can even interfere with the nozzles of the fuel supply pipes from the tanks to the engines. Therefore, as part of the maintenance operations, water has to be drained in certain intervals ensuring that no remaining ice is present. In the absence of an established method for determining residual ice blocks inside, the aircraft operator has to wait long enough, in some cases too long, to start the draining procedure, leading potentially to an unnecessary long ground time. A promising technology to determine melting ice uses acoustic signals generated and emitted during ice melting. With acoustic emissions, mainly situated in the ultrasonic frequency range, a very
Pfeiffer, HelgeReynaert, JohanSeveno, DavidJordaens, Pieter-JanCeyhan, OzlemWevers, Martine
A research program was conducted to evaluate the effectiveness of icing tunnel hybrid model design. A hybrid design is where the full-scale leading edge of a wing section is maintained only to a certain percentage of the local chord, while the aft section of the model is redesigned into a shortened or truncated planform. An initial study was conducted in 2020 where the ice shape geometries on a full-chord length version of the swept CRM65 wing model were compared to those from the hybrid version of CRM65 that were obtained in the NASA Icing Research Tunnel in 2015. The results were reported in a 2021 paper. For most test conditions, the overall size and shape of the ice shapes compared well. However, the ice shapes from the full-chord model were generally slightly smaller than those from the hybrid model. A follow-on test was conducted in 2022 and obtained ice shapes on both full-chord and hybrid wing models during the same test campaign to eliminate the differences in the tunnel spray
Lee, SamBroeren, Andy
The primary objective of this work is to design new type of silencer with perforated inner pipe and nozzles for reducing the sound pressure level in automobile engine. Initialy, the proposed silencer with perforated inner pipe and nozzles was designed and analyzed by using ANSYS-Fluent (Workbench). In this analysis the effect of number of nozzle, convergence angle and position of nozzles were investigated. Based on the simulation results the proposed silencer with perforated inner pipe and nozzles was fabricated. Meanwhile conventional type silencer (with perforated inner pipe and without nozzle) was also fabricated. Both type of silencer were tested in a Kirloskar single-cylinder water-cooled 10hp diesel engine. The sound produced through the outlet of the silencer was measured using the SPL application on the mobile device. The experimental results shows that the silencer with perforated inner pipe and nozzles was having lower sound level and lower engine's backpressure
N, VasirajaPrabhahar R, Saravana Sathiya
These methods of test are applicable for determining the resistance to snagging and abrasion of automotive bodycloth, vinyl, and leather
Textile and Flexible Plastics Committee
For liquid fueled engine, the fuel atomization affects fuel’s evaporation, combustion, noise and vibration characteristics eventually. In this study, the effects of fuel species on the internal flow and near field primary breakup characteristics of a nozzle “Spray C” are investigated. Based on the framework of OpenFOAM, the newly developed solver which coupled cavitation model and the multifluid-quasi-VOF (Volume-of-Fluid) model, and combines the LES (Large Eddy Simulation) are applied to simulate the nozzle inner flow and near field jet breakup when using diesel and biodiesel respectively. The transient characteristics of nozzle inner flow and near field spray of two different fuels were analyzed, and the variation of axial pressure and velocity of nozzle was obtained. The simulation results show that the cavitation of biodiesel with high viscosity and low saturated vapor pressure develops slower and weaker. At the same time, due to the high viscosity of biodiesel, the flow velocity
Liu, CanxuDang, YongjieXi, XiZhang, RunqiLi, WenfeiLiu, Hong
Fuel spray and atomization processes affect the combustion and emissions characteristics of fuels in internal combustion engines. Biodiesel and synthetic fuels such as oxymethylene dimethyl ethers (OME) show great promise as alternative fuels and are complementary in terms of reproducing the fluid properties of conventional diesel fuels through blending, for instance. Averaged experimental results, empirical correlations and Computational Fluid Dynamics (CFD) have typically been used to evaluate and predict fuel spray liquid and vapor penetration values so as to better design internal combustion engines. Lately, Machine Learning (ML) is being applied to these investigations. Typically, ML spray studies use averaged experimental data and then over-trained neural networks on the limited available data. By contrast, in this study we present spray vapor tip penetration predictions using artificial neural networks with systematic treatment of uncertainties arising from experimental
Richards, BrynEmekwuru, Nwabueze
Hydrogen (H2), a potential carbon-neutral fuel, has attracted considerable attention in the automotive industry for transition toward zero-emission. Since the H2 jet dynamics play a significant role in the fuel/air mixing process of direct injection spark ignition (DISI) engines, the current study focuses on experimental and numerical investigation of a low-pressure H2 jet to assess its mixing behavior. In the experimental campaign, high-speed z-type schlieren imaging is applied in a constant volume chamber and H2 jet characteristics (penetration and cross-sectional area) are calculated by MATLAB and Python-based image post-processing. In addition, the Unsteady Reynolds-Averaged Navier-Stokes (URANS) approach is used in the commercial software Star-CCM+ for numerical simulations. The H2 jet dynamics is investigated under the effect of nozzle geometry (single-hole, double-hole, and multiple-hole (5-hole)), which constitutes the novelty of the present research, and pressure ratio (PR
Yeganeh, MaryamRabensteiner, SamuelKarimkashi, ShervinCheng, QiangKaario, OssiLarmi, Martti
The “Water Spider Geometry” (WSG) configuration, representing a newly developed reference test sample designed to suitably investigate the flow and heat transfer processes relevant to cooling systems of internal combustion engines, was computationally investigated by applying a recently proposed Reynolds Stress model called the “Elliptic-Blending Model” (EBM). The WSG configuration resembles a specifically configured pipe geometry that appropriately mimics the flow phenomena encountered in cooling channels of realistic internal combustion engine, such as flow impingement and bifurcation, multiple deflections and flow confluence. The reference database, consisting of mean flow and turbulence fields, was provided by a Large-Eddy Simulation. The EBM formulation has been intensively validated by calculating numerous isothermal wall-bounded flows. The present work focuses on testing the EBM predictive performances under the conditions of non-isothermal flow scenarios. Before proceeding to
Wegt, SebastianBopp, MaximilianKrüger, LouisKlink, ArturReitz, RuedigerHussong, JeanetteJakirlic, Suad
The current transportation fuels have been one of the biggest contributors towards climate change and greenhouse gas emissions. The use of carbon-free fuels has constantly been endorsed through legislations in order to limit the global greenhouse gas emissions. In this regard, ammonia is seen as a potential alternative fuel, because of its carbon-free nature, higher octane number and as hydrogen carrier. Furthermore, many leading maritime companies are doing enormous research and planning projects to utilize ammonia as their future carbon-free fuel by 2050. Flash boiling phenomenon can significantly improve combustion by enhancing the spray breakup process and ammonia possessing low boiling point, has a considerable potential for flash boiling. However, present literature is missing abundant research data on superheated ammonia sprays. Therefore, this research work aims to optically investigate the behavior of ammonia sprays under different conditions of fuel temperatures for varying
Akram, Muhammad SaadYeganeh, MaryamCheng, QiangKaario, OssiLarmi, Martti
Owing to climate change issues caused by global warming, the role of alternative fuels, such as low-carbon and non-carbon fuels, is becoming increasingly important, particularly in the transportation sector. Therefore, hydrogen has emerged as a promising fuel for internal combustion engines because it does not emit carbon dioxide. Direct injection is mandatory for hydrogen-based internal combustion engines to mitigate backfires and low energy density. However, there is a lack of measurement of the equivalence ratio methodology because hydrogen has a higher diffusion rate than conventional fuels. The objective of this research is a feasibility study of laser-induced breakdown spectroscopy (LIBs) for measuring the equivalence ratio. The second harmonic ND-YAG laser was implemented to induce the atomic emission of hydrogen via the breakdown phenomenon. Simultaneously, the hydrogen jet structure was visualized in a constant volume vessel using Schlieren imaging. Therefore, the experimental
Lee, SangukKim, Jungho JustinKi, YoungminKwak, YeseungLee, Seong-Young
Unwanted crops and weeds in California’s Central Valley have been on alert — with residents breathing easier — for the last year thanks to Verdant Robotics. That’s because local tractors have been towing the company’s SprayBox technology: AI robots comprising 50 spray nozzles and a sophisticated computer system that aim to empower farmers with high-fidelity information to improve agricultural yields
The use of converging-diverging (C-D) variable area nozzle (VAN) in military aeroengines is now common, as it can give optimal expansion and control over engine back pressure, for a wide range of engine operations. At higher main combustion temperatures (desired for supercruise), an increase in the nozzle expansion ratio is needed for optimum performance. But changes in the nozzle throat and exit areas affect the visibility of engine hot parts as the diverging section of the nozzle is visible for a full range of view angle from the rear aspect. The solid angle subtended by engine hot parts varies with change in visibility, which affects the aircraft infrared (IR) signature from the rear aspect. This study compares the performances of fixed and variable area nozzles (FAN and VAN) in terms of engine thrust and IR signature of the engine exhaust system in the boresight for the same increase in combustion temperature. This study is performed for two cases: (i) variable throat area and
Baranwal, NidhiMahulikar, Shripad P.
Gasoline compression ignition (GCI) is a promising combustion technology that can help the commercial transportation sector achieve operational flexibility and meet upcoming criteria pollutant regulations. However, high-pressure fuel injection systems (>1000 bar) are needed to enable GCI and fully realize its benefits compared to conventional diesel combustion. This work is a continuation of previous durability studies that identified three key technical risks after running gasoline-like fuel through a heavy-duty, common rail injection system: (i) cavitation damage to the inlet check valve of the high-pressure pump, (ii) loss of injector fueling capacity, (iii) cavitation erosion of the injector nozzle holes. Upgraded hardware solutions were tested on a consistent 400- to 800-hour NATO durability cycle with the same gasoline-like fuel as previous studies. The upgraded pump showed no signs of abnormal wear or cavitation damage to the inlet check valve. In contrast to previous studies
Tzanetakis, TomMedina, RobertoGarg, RajeshPeng, QianMoon, Chi YoungSforzo, Brandon A.Powell , Christopher F.
Cold spray (CS) is a rapidly developing solid-state repair and coating process, wherein metal deposition is produced without significant heating or melting of metal powder. Solid state bonding of powder particles is produced by impact of high-velocity powder particles on a substrate. In CS process, metal powder particles typically of Aluminum or Copper are suspended in light weight carrier gas medium. Here high pressure and high temperature carrier gas is expanded through a converging-diverging nozzle to generate supersonic gas velocity at nozzle exit. The CS process typically uses Helium as the carrier gas due to its low molecular weight, but Helium gas is quite expensive. This warrants a need to explore alternate carrier gases to make the CS repair process more economical. Researchers are exploring another viable option of using pure Nitrogen as a carrier gas due to its significant cost benefits over Helium. However, it shows challenges in achieving desired powder particle velocities
Bhardwaj, DivyanshuBhise, Onkar PSalutagi, Shivayogi SRoberts, Kirstyn
Cavitation is the major cause of the effective flow area reduction in fuel nozzles, together with mechanical damage, which leads to an increase of pressure losses. This paper describes the effect of different geometries along the fuel nozzle holes simulated with OpenFOAM® to control the cavitation and shape of the fuel jet. Previous work has only focused on the development trend towards conical spray holes that tapers towards the outlet with a strong rounded inlet edge, to increase the static pressure and thus reduce the cavitation tendency in nozzles; however, the jet forms a very narrow cone angle. The aim of this study is to evaluate the effect of constricted, expanded and gradually wider nozzles holes. The simulation reveals that the cavitation level can be changed and controlled depending on the geometry of the nozzle holes, the wider the inlet, the less is the cavitation; at the same time, the narrower the outlet, the better is the fuel atomization. Critically, a wider inlet
Gutierrez, MarcosTaco, DianaBösenhofer, MarkusHarasek, MichaelCastillo, AndresIniguez, Juan
This test method covers determination of abrasion resistance, fiber loss, and bearding resistance of automotive carpet materials
Textile and Flexible Plastics Committee
The collision of two or more liquid jets may provide considerable atomisation and efficient mixing of injected substances at the same time. This phenomenon is used, among others, in rocket engines, where the fuel and oxidiser are introduced separately and almost immediately mixed through self-impingement. Depending on the injection and operating conditions, diverse configurations of impinging jets are used, such as doublets, triplets, etc. The appropriately designed injectors and operating conditions ensure the short length of the liquid structures that are developed as a result of the jets’ collision, as well as lead to intensive atomisation. The following work presents a numerical analysis of some impinging jets with relatively high Reynolds numbers. Two different nozzle diameters were considered, which were designed for fuels with different calorific values and stoichiometric ratios. The work aims to investigate the influence of the nozzle diameters on the liquid jets’ interaction
Kazmierski, BartoszKapusta, Łukasz Jan
Mass-production single-cylinder engines are generally not turbocharged due to pulsated exhaust flow. Hence, about one-third of the fuel chemical energy is wasted in the engine exhaust. To extract the exhaust energy and boost the single-cylinder engines, a novel supercharging with a turbo-compounding strategy is proposed in the present work, wherein an impulse turbine extracts energy from the pulsated exhaust gas flow. Employing an impulse turbine for a vehicular application, especially on a single-cylinder engine, has never been commercially attempted. Hence, the design of the impulse turbine assumes higher importance. A nozzle, designed as a stator part of the impulse turbine and placed at the exhaust port to accelerate the flow velocity, was included as part of the layout in the present work. The layout was analyzed using the commercial software AVL BOOST. Different nozzle exit diameters were considered to analyze their effect on the exhaust back pressure and engine performance. A
Ramkumar, JKrishnasamy, AnandRamesh, A
Momentum conservation is a principle rule that affects the behaviour of vapour jet and liquid spray penetration. The air entrainment and mixture formation processes are dominated by the momentum transferred from the fuel to the ambient gas. Thus, it is a significant factor in the development of spray and jet penetration. This mixture formation process is well described for small-scale passenger car injectors; however, it has to be investigated in more detail for large-scale injector nozzles. The current work provides qualitative and quantitative results of spray and jet parameters in a constant volume combustion chamber (CVC). Two optical methods have been utilized to evaluate spray and jet details: Schlieren photography as a method to visualize the jet penetration and cone angle as well as Mie scattering for the phase change evaluation and the determination of liquid spray parameters. The temperature and pressure of inert gas and fuel inside a CVC are set to exemplify engine
Fajri, HamidrezaClemente Mallada, RafaelRiess, SebastianStrauß, LukasWensing, Michael
This study presents experimental and numerical examination of directly injected (DI) propane and iso-octane, surrogates for liquified petroleum gas (LPG) and gasoline, respectively, at various engine like conditions with the overall objective to establish the baseline with regards to fuel delivery required for future high efficiency DI-LPG fueled heavy-duty engines. Sprays for both iso-octane and propane were characterized and the results from the optical diagnostic techniques including high-speed Schlieren and planar Mie scattering imaging were applied to differentiate the liquid-phase regions and the bulk spray phenomenon from single plume behaviors. The experimental results, coupled with high-fidelity internal nozzle-flow simulations were then used to define best practices in CFD Lagrangian spray models. Optical imaging revealed that unlike iso-octane, propane’s spray propagation was fed by its flash boiling, spray collapse, and high degree of vaporization, resulting in a direct
Windell, BryeSharma, ManavNocivelli, LorenzoAsztalos, KatherineZdanowicz, AndrewKar, TanmayOlsen, DanielMarchese, AnthonyWindom, Bret
The temperature of fuel injectors can affect the flow inside nozzles and the subsequent spray and liquid films on the injector tips. These processes are known to impact fuel mixing, combustion and the formation of deposits that can cause engines to go off calibration. However, there is a lack of experimental data for the transient evolution of nozzle temperature throughout engine cycles and the effect of operating conditions on injector tip temperature. Although some measurements of engine surface temperature exist, they have relatively low temporal resolutions and cannot be applied to production injectors due to the requirement for a specialist coating which can interfere with the orifice geometry. To address this knowledge gap, we have developed a high-speed infrared imaging approach to measure the temperature of the nozzle surface inside an optical diesel engine. We investigated ways of increasing the emissivity of the nozzle surface with minimal intrusion by applying thin carbon
Gander, AlexCrua, CyrilSykes, DanSpragg, Robde Sercey, GuillaumePayri, RaulWebb, Cameron
For meeting the stringent BS VI emissions in a 3-cylinder diesel engine the Exhaust after treatment system (EATS) was upgraded from a single brick DOC (diesel oxidation catalyst) to 2 brick DOC+sDPF (Diesel Particulate Filter) configuration. To meet the demands of emission regulation and sDPF requirements, changes were also required in the Fuel injection system. Major changes were done to the fuel injector and fuel pump. This paper primarily discusses the Fuel injector change from 1.1 to 2.2 family with changes in nozzle geometry, Nozzle tip protrusion (NTP), and injector cone angle and the effects on the emission and performance parameters. The various design values of NTP, cone angle, and Sac values are tested in an actual engine to meet the required power, torque and verified to meet NOx, HC, PM values as required by the new BS (Bharat Stage) VI regulation. Other boundary conditions are also checked - BSFC (Brake Specific Fuel Consumption), temperature, etc. The design change that
Vinaya Murthy, VijayendraDharan R, BharaniBoita, DhananjayaraoAmara, Rajesh
Despite the advantages of turbocharging in improved engine performance and reduced exhaust emissions, commercial single-cylinder engines used for automotive applications remain naturally aspirated (NA) and are not generally turbocharged. This is due to the shortcomings with pulsated and intermittent exhaust gas flow into the turbine and the phase lag between the intake and exhaust stroke. In the present study, experimental investigations are initially carried out with a suitable turbocharger closely coupled to a single-cylinder diesel engine. Results indicated that the engine power dropped significantly by 40% for the turbocharged engine compared to the NA version even though the air mass flow rate was increased by at least 1.5 times with turbocharging. A novel approach of decoupling the turbine and the compressor and coupling them separately to the engine is proposed to address these limitations. Also, an impulse turbine is chosen for this application, better suited to extract energy
Ramkumar, JKrishnasamy, AnandRamesh, A
Split injection processes have been analyzed by means of a Quasi-1D spray model that has been recently coupled to a laminar tabulated unsteady-flamelet progress-variable (UFPV) combustion model. The modelling approach can predict ignition delay and lift-off for long injection profiles, and it is now extended to a two-pulse injection scheme. In spite of the simplicity of the approach, relevant phenomena are adequately reproduced. In particular, the faster penetration of the second injection pulse compared to the first one is captured by the model both under inert and reacting conditions. The second pulse ignites much faster than the first one due to the injection into the remnants of the first one, where high temperature oxygen-depleted regions can be found. Ignition of the second pulse happens as soon as the first pulse reaches this region, with a faster low- to high-temperature transition. Parametric variations show a different influence of pulse dwell compared to first pulse duration
Garcia-Oliver, Jose MNovella, RicardoPastor, Jose MCao, Jiawei
Computational models widely employed for predicting the dispersion of fuel sprays in combustion engines suffer from well-known drawbacks associated with the utilization of case-dependent empirical phase-change models, describing the conversion of liquid into vapour during fuel injection. The present work couples the compressible Navier-Stokes and energy conservation equations with a thermodynamic closure approximation covering pressures from 25 to 2000bar and temperatures that expand from compressed liquid, vapor-liquid equilibrium to trans/supercritical mixing, and thus, cover the whole range of P-T values that diesel fuel undergoes during its injection into combustion engines. The model assumes mechanical and thermal equilibrium between the liquid, vapour and surrounding air phases and thus, it avoids utilization of case-dependent empirical phase-change models for predicting in-nozzle cavitation and vaporization of fuels. Model development is based on the recent works reported for
Justino Vaz, Marilia GabrielaGeber, EvangelosKoukouvinis, FoivosKarathanassis, Ioannis K.Rodriguez Fernandez, CarlosGavaises, ManolisMouokue, Gerard
This work presents a numerical study of the Spray A (n-dodecane) characteristics using Eulerian and Lagrangian models in a finite-volume framework. The standard k-ε turbulence model was applied for the spray simulations. For Eulerian simulations, the X-ray measured injector geometries from the Engine Combustion Network (ECN) were employed. The High-Resolution Interface Capturing (HRIC) scheme coupled with a cavitation model was utilized to track the fluid-gas interface. Simulations under both the cool and hot ambient conditions were performed. The effects of various grid sizes, turbulence constants, nozzle geometries, and initial gas volume within the injector sac on the modeling results were evaluated. As indicated by the Eulerian simulation results, no cavitation was observed for the Spray A injector; a minimum mesh size of 15.6 μm could achieve a reasonably convergent criterion; the nominal nozzle geometry predicted similar results to the X-ray measured nozzle geometry. For both the
Liu, XinleiAllehaibi, MoazIm, Hong G.
Items per page:
1 – 50 of 1356