Research of the Atomization Characteristics of Low Pollution Air Blast Nozzle

2013 ◽  
Vol 655-657 ◽  
pp. 133-136
Author(s):  
Kai Liu

Atomization characteristic has great impact about combustion efficiency, ignition performance, and outlet temperature field of combustor. Obtained atomization characteristic about spray particle size and spray cone angle using LDV/PDPA system and the relevant software. The results indicated: particle size decrease rapidly with increasing air and tends to stabilize, Spray cone angle does not change with the air pressure. These experimental data have provided reliable basis for the nozzle group design, development and operation.

2011 ◽  
Vol 66-68 ◽  
pp. 307-310
Author(s):  
Xu Li ◽  
Kai Liu

Experimental investigation results of the fuel nozzle group in a heavy-duty gas turbine are presented. Atomization characteristic has great impact about combustion efficiency, ignition performance, and outlet temperature field of combustor. Obtained atomization characteristic about spray particle size and distribution using LDV/PDPA system. These experimental data have provided reliable basis for the nozzle group design, development and operation.


Author(s):  
Ramachandran Sakthikumar ◽  
Deivandren Sivakumar ◽  
B. N. Raghunandan ◽  
John T. C. Hu

Search for potential alternative jet fuels is intensified in recent years to meet stringent environmental regulations imposed to tackle degraded air quality caused by fossil fuel combustion. The present study describes atomization characteristics of blends of jatropha-derived biofuel with conventional aviation kerosene (Jet A-1) discharging into ambient atmospheric air from a dual-orifice atomizer used in aircraft engines. The biofuel blends are characterized in detail and meet current ASTM D7566 specifications. The experiments are conducted by discharging fuel spray into quiescent atmospheric air in a fuel spray booth to measure spray characteristics such as fuel discharge behavior, spray cone angle, drop size distribution and spray patternation at six different flow conditions. The characteristics of spray cone angle are obtained by capturing images of spray and the measurements of spray drop size distribution are obtained using laser diffraction particle analyzer (LDPA). A mechanical patternator system comprising 144 measurement cells is used to deduce spray patternation at different location from the injector exit. A systematic comparison on the atomization characteristics between the sprays of biofuel blends and the 100% Jet A-1 is presented. The measured spray characteristics of jatropha-derived alternative jet fuels follow the trends obtained for Jet A-1 sprays satisfactorily both in qualitative and quantitative terms.


Author(s):  
M. M. Hasan ◽  
R. Chandrahasan ◽  
S. Ru ◽  
Y. Choi ◽  
J. Lee

Abstract The efficiency of engine combustion is strongly dependent on fuel atomization and spray processes which in turn are greatly influenced by nozzle internal geometry and parameter like air to liquid ratio (ALR). Modern engines employ different geometrically designed nozzles. It is crucial to characterize the effect of the internal geometry of the nozzle and ALR on atomization characteristics. In this study, the effects of geometric parameters of the pressure-swirl duplex nozzle and ALR on the spray characteristics of Jet A-1 fuel were investigated. Two different shaped pilot nozzles and two different shaped main nozzles were used. The analysis of spray characteristics was done by using particle image velocimetry (PIV) system and phase Doppler anemometry (PDA) system. Spray cone angle, Sauter mean diameter (SMD) distribution and weighted mean SMD (WMSMD) were analyzed. In the case of the effect of the internal geometry of the nozzle, the results show that when main and pilot nozzle work together, it produces a higher spray cone angle compared to the pilot nozzle alone. Cone-shaped pilot nozzle tip exhibits better atomization characteristic than flat shaped pilot nozzle tip. Combined main and pilot nozzle with counter-rotating flow provides smaller droplets and higher spray cone angle than co-rotating flow configuration. In the case of the effect of ALR, a decreasing trend in the spray cone angle is found with increasing ALR. Moreover, WMSMD increases with increasing ALR up to 1.16, but thereafter, it decreases again.


2011 ◽  
Vol 12 (3) ◽  
Author(s):  
Ahmad Hussein Abdul Hamid

ABSTRACT : Fuel injector for liquid rocket is a very critical component since that small difference in its design can dramatically affect the combustion efficiency. The primary function of the injector is to break the fuel up into very small droplets. The smaller droplets are necessary for fast quiet ignition and to establish a flame front close to the injector head, thus shorter combustion chamber is possible to be utilized. This paper presents an experimetal investigation of a mono-propellant hollow cone swirl injector. Several injectors with different configuration were investigated under cold flow test, where water is used as simulation fluid. This investigation reveals that higher injection pressure leads to higher spray cone angle. The effect of injection pressure on spray cone angle is more prominent for injector with least number of tangential ports. Furthermore, it was found that injector with the most number of tangential ports and with the smallest tangential port diameter produces the widest resulting spray. Experimental data also tells that the diameter of an air core that forms inside the swirl chamber is largest for the injector with smallest tangential port diameter and least number of tangential ports.ABSTRAK : Injektor bahan api bagi roket cecair merupakan satu komponen yang amat kritikal memandangkan perbezaan kecil dalam reka bentuknya akan secara langsung mempengaruhi kecekapan pembakaran. Fungsi utama injektor adalah untuk memecahkan bahan api kepada titisan yang amat kecil. Titisan kecil penting untuk pembakaran pantas secara senyap dan untuk mewujudkan satu nyalaan di hadapan, berhampiran dengan kepala injektor, maka kebuk pembakaran yang lebih pendek berkemungkinan dapat digunakan. Kertas kerja ini mebentangkan satu penyelidikan eksperimental sebuah injektor ekabahan dorong geronggang kon pusar. Beberapa injektor dengan konfigurasi berbeza telah dikaji di bawah ujian aliran sejuk, di mana air digunakan sebagai bendalir simulasi. Kajian ini mendedahkan bahawa suntikan bertekanan tinggi menghasilkan sudut semburan kon yang besar. Kesan tekanan suntikan ke atas sudut semburan kon lebih ketara pada injektor yang mempunyai lubang tangen yang kurang Tambahan pula, injektor yang mempunyai jumlah lubang tangen yang paling banyak dan lubang tangen berdiameter paling kecil menghasilkan semburan yang paling lebar. Data eksperimental juga menunjukkan bahawa diameter teras udara terbesar terhasil di dalam kebuk pusar injektor yang mempunyai diameter lubang tangen terkecil dan jumlah lubang tangen yang paling kurang.


Author(s):  
Xiongjie Fan ◽  
Cunxi Liu ◽  
Yong Mu ◽  
Yulan Wang ◽  
Kaixing Wang ◽  
...  

In this paper, influences of structure parameters on mass flow and atomization characteristics (spray cone angle, SMD, liquid film fusion and separation) of dual-orifice atomizers were investigated using Fraunhofer diffraction optical instrument and high-speed shadowgraph technique. The main influential structure parameters are obtained by structural parameter sensitivity analysis. Liquid film fusion and separation is an important atomization characteristic lacking of in-depth research. Results of liquid film fusion and separation illustrate that three patterns (separation-fusion-secondary separation) of main stage liquid film and pilot stage liquid film appear with the increase of Δ P. Liquid film fusion makes SMD larger, and there is a delay in liquid film separation when reduce Δ P after liquid film fusion. In addition, mass flow and spray cone angle are key factors which affect liquid film fusion pressure, liquid film secondary separation pressure and distance between two liquid films. The smaller the pilot stage mass flow is, the larger the effect of the main stage on pilot stage spray cone angle will be. Results in this paper could be used to the design and optimization of new dual-orifice atomizers.


2021 ◽  
Vol 13 (6) ◽  
pp. 168781402110248
Author(s):  
Dongling Yu ◽  
Zuoxiang Zhu ◽  
Jiangen Zhou ◽  
Dahai Liao ◽  
Nanxing Wu

In order to predict the atomization characteristics of the atomization process of zirconia dry granulation accurately, the influence of nozzle outlet diameter on the atomization characteristics of the atomization process of zirconia dry granulation is analyzed. The VOF method and RNG k-ε turbulence model are applied to numerically analyze the flow field of pressure-swirl nozzles with different outlet diameters of the atomization process of zirconia dry granulation, and the effects of outlet diameters on the spray cone angle, liquid film thickness, pressure distribution and velocity distribution are analyzed. The result shows that when the outlet diameter is increased from 3 to 4 mm, the diameter of air core and the outlet velocity of atomized liquid are increased, the spray cone angle is increased from 30.5° to 59.7° while the liquid film thickness is decreased, but when the outlet diameter is increased to 5 mm, the diameter of air core and the outlet velocity of atomized liquid are decreased, the spray cone angle is decreased to 27.6°, while the thickness of liquid film is decreased. The spray cone angle, moisture content of zirconia particles corresponding to nozzles with different outlet diameters are measured by the design of atomization experiment platform and the microstructure of zirconia particles are observed, which verifies the correctness of numerical analysis. Taking the atomization performance of nozzle into consideration, the pressure-swirl nozzle with the outlet diameter of 4 mm is better suitable for the atomization process of zirconia dry granulation.


Author(s):  
Ronith Stanly ◽  
Gopakumar Parameswaran ◽  
Bibin Sagaram

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.


Author(s):  
Dieter Bohn ◽  
James F. Willie ◽  
Nils Ohlendorf

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.


Author(s):  
Kristen Bishop ◽  
William Allan

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.


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