scholarly journals Numerical Analysis of Fuel Injector Nozzle Geometry - Influence on Liquid Fuel Contraction Coefficient and Reynolds Number

2019 ◽  
Vol 57 (1) ◽  
pp. 23-45
Author(s):  
Lino Kocijel ◽  
Vedran Mrzljak ◽  
Maida Čohodar Husić ◽  
Ahmet Čekić
Keyword(s):  
Reynolds Number ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Injection Rate ◽  
Nozzle Diameter ◽  
Nozzle Geometry ◽  
Fuel Injector ◽  
Contraction Coefficient ◽  
Nozzle Length ◽  
Injector Nozzle

This paper investigates the influence of the fuel injector nozzle geometry on the liquid fuel contraction coefficient and Reynolds number. The main three fuel injector nozzle geometry parameters: nozzle diameter (d), nozzle length (l) and nozzle inlet radius (r) have a strong influence on the liquid fuel contraction coefficient and Reynolds number. The variation of the nozzle geometry variables at different liquid fuel pressures, temperatures and injection rates was analyzed. The liquid fuel contraction coefficient and Reynolds number increase with an increase in the nozzle diameter, regardless of the fuel injection rate. An increase in the r/d ratio causes an increase in the fuel contraction coefficient, but the increase is not significant after r/d = 0.1. A nozzle length increase causes a decrease in the fuel contraction coefficient. Increase in the nozzle length of 0.5 mm causes an approximately similar decrease in the contraction coefficient at any fuel pressure and any nozzle length. Fuel injectors should operate with minimal possible nozzle lengths in order to obtain higher fuel contraction coefficients.

Advanced Fuel Injection System Using a Supercavitating Fuel Injector

2015 ◽  
Author(s):  
John M. Gattoni ◽  
David M. Sykes ◽  
Paul E. Yelvington
Keyword(s):  
Droplet Size ◽  
High Speed ◽  
Fuel Injection ◽  
Injection System ◽  
Nozzle Geometry ◽  
Fuel Injection System ◽  
Fuel Injector ◽  
Penetration Length ◽  
Injector Nozzle ◽  
Fuel Delivery

Using the latest manufacturing technology and patented nozzle geometry, an innovative high-speed (two or more injections at an engine operating speed of 6,000 RPM), lightweight fuel injection system was developed that controls supercavitation within the fuel injector nozzle. The patented supercavitating fuel injector nozzle reduces the penetration length of the fuel spray by 25–30%, average droplet size by 15.5% when operating at the same fuel pressure, and improves droplet size uniformity over conventional nozzles. The combination of these properties represents a tremendous opportunity to improve fuel delivery in engines. In addition to the performance benefits, this technology could be easily implemented into any direct-injected engine system, both compression ignition and spark ignition engines, reciprocating and rotary, because only the nozzle assembly needs to be developed for that particular fuel injector platform.

scholarly journals Modeling a fuel injector for a two-stroke diesel engine

2017 ◽  
Vol 170 (3) ◽  
pp. 147-153
Author(s):  
Rafał SOCHACZEWSKI ◽  
Zbigniew CZYŻ ◽  
Ksenia SIADKOWSKA
Keyword(s):  
Diesel Engine ◽  
Combustion Chamber ◽  
Fuel Injection ◽  
Maximum Load ◽  
Fuel Injector ◽  
Dimensional Model ◽  
Flow Area ◽  
Fuel Mass ◽  
One Dimensional ◽  
Injector Nozzle

This paper discusses the modeling of a fuel injector to be applied in a two-stroke diesel engine. A one-dimensional model of a diesel injector was modeled in the AVL Hydsim. The research assumption is that the combustion chamber will be supplied with one or two spray injectors with a defined number of nozzle holes. The diameter of the nozzle holes was calculated for the defined options to provide a correct fuel amount for idling and the maximum load. There was examined the fuel mass per injection and efficient flow area. The studies enabled us to optimize the injector nozzle, given the option of fuel injection into the combustion chamber to be followed.

Towards Primary Breakup Simulation of a Complete Aircraft Nozzle at Realistic Aircraft Conditions

2020 ◽  
Author(s):  
Katharina Warncke ◽  
Amsini Sadiki ◽  
Max Staufer ◽  
Christian Hasse ◽  
Johannes Janicka
Keyword(s):  
Numerical Simulations ◽  
Liquid Fuel ◽  
Fuel Injection ◽  
Operating Conditions ◽  
Nozzle Geometry ◽  
Nozzle Flow ◽  
Spray Characteristics ◽  
Wide Range ◽  
Primary Breakup ◽  
Turbulent Scales

Abstract Predicting details of aircraft engine combustion by means of numerical simulations requires reliable information about spray characteristics from liquid fuel injection. However, details of liquid fuel injection are not well documented. Indeed, standard droplet distributions are usually utilized in Euler-Lagrange simulations of combustion. Typically, airblast injectors are employed to atomize the liquid fuel by feeding a thin liquid film in the shear zone between two swirled air flows. Unfortunately, droplet data for the wide range of operating conditions during a flight is not available. Focusing on numerical simulations, Direct Numerical simulations (DNS) of full nozzle designs are nowadays out of scope. Reducing numerical costs, but still considering the full nozzle flow, the embedded DNS methodology (eDNS) has been introduced within a Volume of Fluid framework (Sauer et al., Atomization and Sprays, vol. 26, pp. 187–215, 2016). Thereby, DNS domain is kept as small as possible by reducing it to the primary breakup zone. It is then embedded in a Large Eddy Simulation (LES) of the turbulent nozzle flow. This way, realistic turbulent scales of the nozzle flow are included, when simulating primary breakup. Previous studies of a generic atomizer configuration proved that turbulence in the gaseous flow has significant impact on liquid disintegration and should be included in primary breakup simulations (Warncke et al., ILASS Europe, Paris, 2019). In this contribution, an industrial airblast atomizer is numerically investigated for the first time using the eDNS approach. The complete nozzle geometry is simulated, considering all relevant features of the flow. Three steps are necessary: 1. LES of the gaseous nozzle flow until a statistically stationary flow is reached. 2. Position and refinement of the DNS domain. Due to the annular nozzle design the DNS domain is chosen as a ring. It comprises the atomizing edge, where the liquid is brought between inner and outer air flow, and the downstream primary breakup zone. 3. Start of liquid fuel injection and primary breakup simulation. Since the simulation of the two-phase DNS and the LES of the surrounding nozzle flow are conducted at the same time, turbulent scales of the gas flow are directly transferred to the DNS domain. The applicability of eDNS to full nozzle designs is demonstrated and details of primary breakup at the nozzle outlet are presented. In particular a discussion of the phenomenological breakup process and spray characteristics is provided.

The Sensitivity of Inner Nozzle Flow in Gasoline Direct Injection Injector to the Nozzle Geometry Parameters

2019 ◽  
Vol 141 (6) ◽  
Author(s):  
Xinhai Li ◽  
Yong Cheng ◽  
Xiaoyan Ma ◽  
Xue Yang
Keyword(s):  
Structural Parameters ◽  
Direct Injection ◽  
Large Diameter ◽  
Small Diameter ◽  
Flow Characteristics ◽  
Gasoline Direct Injection ◽  
Nozzle Geometry ◽  
Nozzle Flow ◽  
Nozzle Length ◽  
Injector Nozzle

The inner-flow of gasoline direct injection (GDI) injector nozzles plays an important role in the process of spray, and affects the mixture process in gasoline engine cylinder. The nozzle structure also affects the inner-flow of GDI injector. In order to obtain uniform performance of GDI injector, the size consistency of injector nozzle should be ensured. This paper researches the effect of nozzle length and diameter on the inner flow and analyzes the sensitivity of inner flow characteristics to these structural parameters. First, this paper reveals the process of inception, development, and saturated condition of cavitation phenomenon in injector nozzle. Second, the inner-nozzle flow characteristics are more sensitive to small diameter than large diameter under the short nozzle length, while the sensitivity of the inner-nozzle flow characteristics to large nozzle diameter becomes strong as the increase of the nozzle length. Finally, the influence of nozzle angle on the injection mass flow is studied, and the single nozzle fuel mass will increase as the decrease of nozzle angle α. And the sensitivity of inner-flow characteristic to nozzle angle becomes strong as the decrease of α.

Experimental Study on the Effects of Injector Nozzle and Piston Bowl Geometry on Combustion and Performance in Medium-Speed Diesel Engines

2007 ◽  
Author(s):  
Byong-Seok Kim ◽  
Ki-Doo Kim ◽  
Wook-Hyeon Yoon ◽  
Seung-Hyup Ryu
Keyword(s):  
Engine Performance ◽  
Nox Emission ◽  
Fuel Oil ◽  
Nozzle Geometry ◽  
Fuel Injector ◽  
Oil Consumption ◽  
Piston Bowl ◽  
Injector Nozzle ◽  
Current Limit ◽  
Medium Speed

In recent years, many regulations of exhaust gas emissions have been enhanced in not only automotive engines but also marine and power generation engines. So we have done the various studies to reduce NOx in a medium speed diesel engine, HYUNDAI HiMSEN, for satisfying the next IMO(International Maritime Organization) regulation (Tier2, 20∼30% reduction for current limit). The selected parameters for in this study are fuel injector nozzle and piston bowl geometry. These have significant effect on engine performance and combustion. In this study, engine performance experiments have been carried out to investigate the effects of fuel injector nozzle geometry including the nozzle hole diameter, hole number, hole length, and injection angle on the fuel oil consumption and NOx emission of HYUNDAI HiMSEN engine. Also experiments have been carried out to evaluate engine performance and combustion with changing piston bowl geometry including the diameter and depth of piston bowl. The measured parameters of engine performance include cylinder pressure, fuel pump pressure, injection pressure, and heat release rate and NOx, etc. We could find out the optimum point of the nozzle geometry and the piston bowl shape regarding to the trade-off curve on fuel oil consumption versus NOx emission to minimize fuel oil consumption and to satisfy NOx regulation of HYUNDAI HiMSEN engines.

scholarly journals Modern Technologies for Micro-drilling of the Fuel Injector Nozzle used in Motor Vehicles - A Review of the Literature

2021 ◽  
Vol 343 ◽  
pp. 03007
Author(s):  
Dorinel Popa ◽  
Cristin-Olimpiu Morariu
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Production Capacity ◽  
Motor Vehicles ◽  
Drilling Process ◽  
Fuel Injector ◽  
Pilot Hole ◽  
Injector Nozzle ◽  
Electro Discharge Machining ◽  
Micro Drilling

To cope with the pollution norms and an improvement of the combustion of the internal combustion engines, high-quality holes with diameters smaller than 145 µm are needed for the manufacture of fuel injection nozzles. The current practice of using drilling by electro-discharge machining of fuel injection nozzles is limited in terms of the size of the hole it can efficiently produce and the time required for drilling. In addition, the cost of the tool is high. This paper presents an investigation into a sequential laser and electro-discharge micro-drilling technique for the manufacture of fuel injection nozzles. A pilot hole drilled with a laser is removed by electrodischarge. It was found that this hybrid process eliminated the problems of reformed and heat-affected areas usually associated with the laser drilling process. The new process has allowed a reduction in total drilling time compared to standard electro-discharge machining drilling, as less material is removed from the electro-discharge machining. The quality of the holes is as good as direct electro-discharge machining drilling. This technique has allowed valuable cost savings and increased production capacity for the manufacture of the fuel injector nozzle.

scholarly journals Fuel Injector Testing Through Development of a New Test Rig

2019 ◽  
Vol 8 (9) ◽  
pp. 2904-2909
Keyword(s):  
Fuel Injection ◽  
Cylinder Liner ◽  
Heating System ◽  
Injection Rate ◽  
Engine Fuel ◽  
Exhaust Manifold ◽  
Fuel Injector ◽  
Test Rig ◽  
Recirculation System ◽  
Fuel Injection Rate

A modified version of fuel injector with higher injection capacity has been developed. To achieve this, the injector plunger diameter is increased to 11mm from current 9.5mm. A new test rig is developed to understand the functioning of the injector due to the changes incorporated. The new test rig is designed to test injector operation without burning the fuel. Since internal combustion is not present an external arrangement is required to run the engine. This is achieved through a 3-phase induction motor, which is coupled with the crankshaft of the engine. The injected fuel is collected form the cylinders and it is then recirculated. A fuel cooling circuit is also incorporated along with the fuel recirculation system to maintain the temperature of fuel at inlet of fuel pump. An oil heating system is installed in the test rig to maintain the viscosity of the oil by heating it. The required systems for driving the engine, fuel cooling and oil heating are implemented as per the design. The test is conducted on a 19 L diesel engine. Parts which are not required for this test like piston, piston rings, intake and exhaust manifold etc are removed from the engine. And the cylinder liner is blocked from below using a plate to facilitate the collection of injected fuel. Engine is made to run using the motoring rig at the rated speed of 1500 rpm for a duration of 250 hours. Instrumented push tubes are used to measure the push tube load. Push tube load is observed to be in the range of 2700 to 3100 lbf, which is high as compared to the earlier model of the injector. Fuel injection rate is obtained from the fuel collected from the cylinders. And the average fuel injection rate is observed as 0.116 to 2.35 kg/min. Thus, the increase in plunger diameter has led to an increase in fuel injection rate

An Instrument for Measuring Orifice-Specific Fuel-Injection Rate From a Multi-Orifice Nozzle

2008 ◽  
Author(s):  
Jason G. Kempenaar ◽  
Charles J. Mueller ◽  
Kim A. Shollenberger ◽  
Krishna Lakshminarasimhan
Keyword(s):  
Fuel Injection ◽  
Injection Rate ◽  
Geometric Constraints ◽  
Thermal Shield ◽  
Injector Nozzle ◽  
Compression Ignition Engines ◽  
Fuel Flow ◽  
Transducer Output ◽  
Effects Of Temperature ◽  
Fuel Injection Rate

Understanding fuel-injection processes is important for improving combustion in compression-ignition engines. To understand and model injection processes in detail, it is necessary to measure the instantaneous mass flow rate of fuel through each orifice of the injector nozzle. Due to constraints from injector design and operation, injection rate is typically measured downstream from the orifice exit. Measuring injection rate from a multi-orifice nozzle adds several geometric constraints, particularly when measuring fuel flow from a single orifice. The injection ratemeter discussed in this paper is designed to fit inside an optical research engine so that the injection rate can be measured without having to place the injector in an external fixture. The injection rate is calculated from a measurement of the momentum flux of a jet of fuel impinging upon the surface of a piezoelectric force (or pressure) transducer, combined with a measurement of the quantity of fuel injected, as demonstrated previously [1–3]. The ratemeter includes a thermal shield to limit the effects of temperature fluctuations on the transducer output. Data were acquired for one injector nozzle at several different injection durations and compared to results from literature for similar injector designs. Estimates for the uncertainty of the measured injection rates are provided and the calibration technique used is presented.

scholarly journals Sensitivity Analysis of Fuel Injection Characteristics of GDI Injector to Injector Nozzle Diameter

Energies ◽  
2019 ◽  
Vol 12 (3) ◽  
pp. 434 ◽  
Author(s):  
Xinhai Li ◽  
Yong Cheng ◽  
Shaobo Ji ◽  
Xue Yang ◽  
Lu Wang
Keyword(s):  
Cfd Simulation ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Nozzle Diameter ◽  
Gasoline Direct Injection ◽  
Small Range ◽  
Fuel Mass ◽  
Single Hole ◽  
Injector Nozzle ◽  
The Difference

The accuracy of a nozzle diameter directly affects the difference of the injection characteristics between the holes and productions of a GDI (gasoline direct injection) injector. In order to reduce the difference and guarantee uniform injection characteristics, this paper carried out a CFD simulation of the effect of nozzle diameter which fluctuated in a small range on single-cycle fuel mass. The sensitivity of the fuel injection quantity to the injector nozzle diameter was obtained. The results showed that the liquid phase ratio at the nozzle outlet decreased and the velocity of the outlet increased with the increase of the nozzle diameter. When fluctuating in a small range of nozzle diameters, the sensitivity of the single-hole fuel mass to the nozzle diameter remained constant. The increase of the injection pressure lead to the increase of the sensitivity coefficient of the single-hole fuel mass to the nozzle diameter. The development of cavitation in the nozzle and the deviation of the fuel jet from the axis were aggravated with the increase of the injection pressure. However, the fluctuation in a small range of nozzles had little effect on the near-nozzle flow.

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