Method of Identifying Injector Coking From the Spray Field of Mechanical and CRDi Injectors Using Intensity of Scattered Light

2017 ◽  
Vol 140 (2) ◽  
Author(s):  
Ronith Stanly ◽  
Gopakumar Parameswaran ◽  
Bibin Sagaram
Keyword(s):  
Scattered Light ◽  
Near Field ◽  
Cone Angle ◽  
Angle Measurement ◽  
Field Region ◽  
Fuel System ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Cleaning Procedure ◽  
Spray Field

The influence of injector coking deposits on the spray field of single-hole mechanical port fuel injectors and multihole common rail direct injection (CRDi) injectors was studied using light scattering technique coupled with image processing and analysis. Instead of employing the traditional accelerated coking process to study injector spray field deterioration, in-service injectors were selected and cleaned using a commercial fuel system cleaning procedure. Variation in atomization characteristics of coked and cleaned injectors were observed based on the spatial distribution of fine, medium, and coarse droplets in the near-field region of the injector spray zone and analyzed as a function of the intensity of scattered light. The improvement in the atomization perceived by this method was compared with traditional techniques like spray cone angle measurement, speed characterization of spray jets, and weight reduction of injector nozzles and needles. It was observed that after the fuel system cleaning procedure, a reduction in the number of coarse droplets in the near-field region and an increase in the number of medium and finely sized droplets was observed, suggesting better atomization of fuel in the near field spray zone.

Experimental Study on Spray Pattern of Pressure-Swirl Nozzle in Reactor Containment

2018 ◽  
Author(s):  
Jiawei Bian ◽  
Dalin Zhang ◽  
Rulei Sun ◽  
Yingwei Wu ◽  
Wenxi Tian ◽  
...  
Keyword(s):  
Experimental Study ◽  
Optimization Design ◽  
Flux Distribution ◽  
Cone Angle ◽  
Distribution Models ◽  
Spray Droplet ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Spray Field ◽  
Pressure Swirl

Spraying system plays an important role in the safety of PWR. To ensure homogeneous spraying of the containment, the layout of nozzles on the spray header was taken into consideration in design. In this paper, an experimental study was conducted to obtain spray characteristics data, including spray cone angle and 2-D spray flux distribution for the purpose of achieving optimal design of the spraying system. According to the specialty of the spray field involved, a testing loop with four pressure-swirl nozzles was established for the study. Spray cone angles were obtained by photograph method. The volume flux distribution was measured by collecting the spray droplet along the cross-section diameters. Based on the experimental data, typical spray flux distributions were obtained. The flux distribution results were used to build 3-D coverage models. Then these models were used to calculate the overall spray coverage in the containment. The present work introduces the experimental study of spray behavior of a typical pressure-swirl nozzle in containment and the method to evaluate spray coverage through building 3-D spray flux distribution models. The work is expected to be helpful for the optimization design of spraying systems.

Experiments on Spray Interactions in the Wake of a Bluff Body

1988 ◽  
Vol 110 (1) ◽  
pp. 86-93 ◽  
Author(s):  
R. C. Rudoff ◽  
M. J. Houser ◽  
W. D. Bachalo
Keyword(s):  
Drop Size ◽  
Bluff Body ◽  
Cone Angle ◽  
Field Interaction ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
General Direction ◽  
Size Classes ◽  
Toroidal Vortices ◽  
Spray Field

The dynamics of spray drop interaction within the turbulent wake of a bluff body were investigated using the Aerometrics Phase Doppler Particle Analyzer, which determines both drop size and velocity. Detailed measurements obtained included spray drop size, axial and radial velocity, angle of trajectory, and size-velocity correlations. The gas-phase flow field was also ascertained via the behavior of the smallest drops. Results showed dramatic differences in drop behavior when interacting with turbulence for the various size classes. Small drops were recirculated in a pair of toroidal vortices located behind the bluff body, whereas the larger drops followed the general direction of the spray cone angle. This was documented via backlit photography. Local changes in number density were produced as a result of lateral convection and streamwise accelerations and decelerations of various drop size classes. The spray field interaction illustrated by these data effectively reveals the complexity associated with the development of the spray and casts some doubts toward attempting to describe sprays via simple integral quantities such as the Sauter mean diameter.

Experimental and Numerical Studies of Diesel Spray Evaporation and Combustion in a Gas Turbine Matrix Burner

2009 ◽  
Author(s):  
Dieter Bohn ◽  
James F. Willie ◽  
Nils Ohlendorf
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Combustion Instability ◽  
Cone Angle ◽  
Spray Angle ◽  
Test Rig ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Flow Simulations ◽  
Air Inlet

Lean gas turbine combustion instability and control is currently a subject of interest for many researchers. The motivation for running gas turbines lean is to reduce NOx emissions. For this reason gas turbine combustors are being design using the Lean Premixed Prevaporized (LPP) concept. In this concept, the liquid fuel must first be atomized, vaporized and thoroughly premixed with the oxidizer before it enters the combustion chamber. One problem that is associated with running gas turbines lean and premixed is that they are prone to combustion instability. The matrix burner test rig at the Institute of Steam and Gas Turbines at the RWTH Aachen University is no exception. This matrix burner is suitable for simulating the conditions prevailing in stationary gas turbines. Till now this burner could handle only gaseous fuel injection. It is important for gas turbines in operation to be able to handle both gaseous and liquid fuels though. This paper reports the modification of this test rig in order for it to be able to handle both gaseous and liquid primary fuels. Many design issues like the number and position of injectors, the spray angle, nozzle type, droplet size distribution, etc. were considered. Starting with the determination of the spray cone angle from measurements, CFD was used in the initial design to determine the optimum position and number of injectors from cold flow simulations. This was followed by hot flow simulations to determine the dynamic behavior of the flame first without any forcing at the air inlet and with forcing at the air inlet. The effect of the forcing on the atomization is determined and discussed.

Effects of Fuel Nozzle Condition on Gas Turbine Combustion Chamber Exit Temperature Distributions

2010 ◽  
Author(s):  
Kristen Bishop ◽  
William Allan
Keyword(s):  
Combustion Chamber ◽  
Ambient Pressure ◽  
Cone Angle ◽  
Operating Conditions ◽  
Spray Cone Angle ◽  
Mixing Processes ◽  
Spray Cone ◽  
Temperature Distributions ◽  
Fuel Nozzle ◽  
Exit Temperature

The effects of fuel nozzle condition on the temperature distributions experienced by the nozzle guide vanes have been investigated using an optical patternator. Average spray cone angle, symmetry, and fuel streaks were quantified. An ambient pressure and temperature combustion chamber test rig was used to capture exit temperature distributions and to determine the pattern factor. The rig tests matched representative engine operating conditions by matching Mach number, equivalence ratio, and fuel droplet size. It was observed that very small deviations (± 10° in spray cone angle) from a nominal distribution in the fuel nozzle spray pattern correlated to increases in pattern factor, apparently due to a degradation of mixing processes, which created larger regions of very high temperature core flow and smaller regions of cooler temperatures within the combustion chamber exit plane. The spray cone angle had the most measureable influence while the effects of spray roundness and streak intensity had slightly less influence. Comparisons were made with published studies conducted on the combustion chamber geometry, and recommendations were made for fuel nozzle inspections.

scholarly journals Experimental Study of Spray Characteristics of Kerosene-Ethanol Blends from a Pressure-Swirl Nozzle

2018 ◽  
Vol 2018 ◽  
pp. 1-14 ◽  
Author(s):  
Tao Zhang ◽  
Bo Dong ◽  
Xun Zhou ◽  
Linan Guan ◽  
Weizhong Li ◽  
...  
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Injection Pressure ◽  
Spray Characteristics ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Ethanol Blends ◽  
Pressure Swirl ◽  
Spray Velocity

Partial replacement of kerosene by ethanol in a gas turbine is regarded as a good way to improve the spray quality and reduce the fossil energy consumption. The present work is aimed at studying the spray characteristics of kerosene-ethanol blends discharging from a pressure-swirl nozzle. The spray cone angle, discharge coefficient, breakup length, and velocity distribution are obtained by particle image velocimetry, while droplet size is acquired by particle/droplet imaging analysis. Kerosene, E10 (10% ethanol, 90% kerosene), E20 (20% ethanol, 80% kerosene), and E30 (30% ethanol, 70% kerosene) have been considered under the injection pressure of 0.1–1 MPa. The results show that as injection pressure is increased, the discharge coefficient and breakup length decrease, while the spray cone angle, drop size, and spray velocity increase. Meanwhile, the drop size decreases and the spray velocity increases with ethanol concentration when the injection pressure is lower than 0.8 MPa. However, the spray characteristics are not affected obviously by the ethanol concentration when the injection pressure exceeds 0.8 MPa. A relation to breakup length for kerosene-ethanol blends is obtained. The findings demonstrate that the adding of ethanol into kerosene can promote atomization performance.

scholarly journals Dynamic Response of Fuel Nozzles for Liquid-Fueled Gas Turbine Combustors

1996 ◽  
Author(s):  
Mounir Ibrahim ◽  
Terry Sanders ◽  
Douglas Darling ◽  
Michelle Zaller
Keyword(s):  
Gas Turbine ◽  
Cone Angle ◽  
Outer Region ◽  
Test Fluid ◽  
Mean Flow ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Gas Turbine Combustors ◽  
The Mean ◽  
Piezoelectric Drive

To imitate resonances that might occur in the fuel delivery system of gas turbine combustors, the incoming liquid streams of two pressure swirl nozzles were perturbed using a piezoelectric driver. Frequencies of perturbations examined were from 3 to 20 kHz, and water was used as the test fluid. A video camera and a Phase Doppler Particle Analyzer (PDPA) were used to study the effect of perturbations on the mean flow quantities of the sprays. Various lighting arrangements were used for the video photography: back lighting, front lighting, a strobe synchronized with the input to the piezoelectric, and a laser sheet oriented along the midplane of the sprays. The study showed that the piezoelectric drive had an effect an the spray system at discrete frequencies. At these particular frequencies, by increasing the input voltage, it was found that the piezoelectric drive affected the atomization in the following ways: (1) the mean flow rate decreased, (2) the spray cone angle decreased, (3) the break up length decreased, (4) the peak of the spatial distribution of the mean droplet size decreased, and (5) the mean droplet sizes and velocities increased near the spray center line and decreased in the outer region of the spray. A hysteresis effect of the drive frequency on the spray cone angle was observed. The results indicated that more fundamental research is needed to gain an in-depth understanding of the physical processes induced in the spray by the piezoelectric drive.

scholarly journals Experimental study on the effect of spray cone angle on the characteristics of horizontal jet spray flame under sub-atmospheric pressure

2020 ◽  
Vol 24 (5 Part A) ◽  
pp. 2941-2952 ◽  
Author(s):  
Kai Xie ◽  
Xingqi Qiu ◽  
Yunjing Cui ◽  
Jianxin Wang
Keyword(s):  
Atmospheric Pressure ◽  
Cone Angle ◽  
Flame Temperature ◽  
Normal Pressure ◽  
Low Pressure ◽  
Dimensionless Temperature ◽  
Thermal Imager ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Matlab Programming

The burning state of a plateau environment is attracting more and more attention. In this paper, in order to have a deeper scientific understanding of diesel spray combustion and the characteristics of a flame under different spray cone angles in a plateau environment, experiments were carried out in a low pressure chamber. The flame morphology was recorded by a high speed video instrument, and the temperature change was recorded by a thermal imager and thermocouples. The MATLAB programming was used to process the video image of the flame, and the probability of its binarization was calculated. The results indicate that the flame becomes longer and wider under different pressures with the same spray angle. The variation is more pronounced at a smaller spray taper angle. The flame uplifted height characteristic is mainly negatively related to the atmospheric pressure. According to the normalized flame temperature and the dimensionless horizontal projection, the length can be divided into three regions. In the region of buoyancy flame, the dimensionless temperature varies with sub-atmospheric pressure more than with normal pressure. In addition, under different spray cone angle conditions, the law of variation in the normalized flame temperature under sub-atmospheric pressure is exactly opposite to that under normal pressure. This study is of great significance to the scientific research on flames in a low pressure environment, and the design of different fuel nozzles for application in a plateau environment.

scholarly journals Calculation of flow characteristics of liquid fuel supplied through pressure jet atomizers of small-sized gas turbine engines

2021 ◽  
Vol 20 (2) ◽  
pp. 19-35
Author(s):  
N. I. Gurakov ◽  
I. A. Zubrilin ◽  
M. Hernandez Morales ◽  
D. V. Yakushkin ◽  
A. A. Didenko ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Liquid Fuel ◽  
Cone Angle ◽  
Flow Characteristics ◽  
Design Parameters ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Semi Empirical

The paper presents the results of studying the flow characteristics of liquid fuel in pressure jet atomizers of small-sized gas turbine engines with nozzle diameters of 0.4-0.6 mm for various operating and design parameters. The study was carried out using experimental measurements, semi-empirical correlations and CFD (computational fluid dynamics) methods. The Euler approach, the volume- of- fluid (VOF) method, was used to model multiphase flows in CFD simulations. Good agreement was obtained between experimental and predicted data on the fuel coefficient and the primary spray cone angle at the nozzle outlet. Besides, the assessment of the applicability of semi-empirical techniques for the nozzle configurations under consideration is given. In the future, the flow characteristics in question (the nozzle flow rate, the fuel film thickness, and the primary spray cone angle) can be used to determine the mean diameter of the droplets (SMD) required to fully determine the boundary conditions of fuel injection when modeling combustion processes in combustion chambers of small-sized gas turbine engines.

Effect of Nanoparticles on the Fuel Properties and Spray Performance of Aviation Turbine Fuel

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Kumaran Kannaiyan ◽  
Kanjirakat Anoop ◽  
Reza Sadr
Keyword(s):  
Surface Tension ◽  
Physical Properties ◽  
Droplet Diameter ◽  
Cone Angle ◽  
Aviation Fuel ◽  
Alumina Nanoparticles ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Breakup Length ◽  
Sheet Breakup

The influence of nanoparticles' dispersion on the physical properties of aviation fuel and its spray performance has been investigated in this work. To this end, the conventional Jet A-1 aviation fuel and its mixtures with alumina nanoparticles (nanofuel) at different weight concentrations are investigated. The key fuel physical properties such as density, viscosity, and surface tension that are of importance to the fuel atomization process are measured for the base fuel and nanofuels. The macroscopic spray features like spray cone angle and sheet breakup length are determined using the shadowgraph technique. The microscopic spray characteristics such as droplet diameter, droplet velocity, and their distributions are also measured by employing phase Doppler anemometry (PDA) technique. The spray performance is measured at two nozzle injection pressures of 0.3 and 0.9 MPa. The results show that with the increase in nanoparticle concentrations in the base fuel, the fuel viscosity and density increase, whereas the surface tension decreases. On the spray performance, the liquid sheet breakup length decreases with increasing nanoparticle concentrations. Furthermore, the mean droplet diameters of nanofuel are found to be lower than those of the base fuel.

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