• Proceedings of the KSME Conference
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• 2001.11b
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• pp.341-346
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• 2001

The gun-type gas burner adopted in this study is generally composed of some slits and swirl vanes. Therefore, this paper is studied to investigate the effect of slits and swirl vanes on the turbulent flow fields in the horizontal plane of gas swirl burner with a cone type baffle plate measured by using X-probe from hot-wire anemometer system. This experiment is carried out at flow rate $450\;{\ell}/min$, which is equivalent to the combustion air flow rate necessary for heat release 15,000 kcal/hr in gas furnace, in the test section of subsonic wind tunnel. When the burner has only swirl vanes, the axial mean velocity component shows the characteristic that spreads more remarkably toward radial direction than axial one, but when it has only slits, that is developed spreading more toward axial direction than radial one. Therefore, because the biggest speed is spurted in slits and it derive main flow toward axial direction encircling rotational flow that comes out from swirl vane that is situated on the inside of slits, both slits and swirl vanes composing of cone type gas burner act role that decreases the speed near slits and increases the flow speed in the central part of a burner. Moreover, because rotational flow by swirl vanes and fast jet flow by slits increase turbulent intensities effectively coexisting, the turbulent kinetic energy is distributed with a bigger size fairly near slits than burner models which have only slit or swirl vanes within X/R<0.6410.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.9
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• pp.1299-1308
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• 2003

This paper is studied to investigate the effect of slits and swirl vanes on the development of turbulent flow fields in gun-type gas burner with a cone type baffle plate because this gas burner is generally composed of eight slits and swirl vanes. All of turbulent characteristics including mean velocities were measured in the horizontal plane and cross section by using X-type hot-wire probe from hot-wire anemometer system. This experiment is carried out at flow rate 450 l/min in the test section of subsonic wind tunnel. Slits cause the fast jets, and then they have the characteristic that the flow is not adequately spread to radial direction and has long flow length and very small flow velocity distribution in the central part. On the contrary, swirl vanes does not have long enough for adequate flow length to downstream because the rotational flow diffuses remarkably to radial direction. However, the suitable arrangement between slits and swirl vanes causes effective flow width and flow length, and then it promotes fast flow mixing over the entire region including central part to increase turbulence more largely and effectively. Therefore, it is thought as a very desirable design method in gun-type gas burner to locate slits on the outside of swirl vanes.

• Journal of ILASS-Korea
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• v.22 no.4
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• pp.159-168
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• 2017

Numerical studies on the spray characteristics of closed-type and open-type swirl injectors were conducted using ANSYS Fluent. By changing injection pressures, discharge coefficient and spray angle were calculated using the Reynolds stress BSL turbulent model. The numerical results were compared with previous experimental data to examine their accuracy. For a closed-type swirl injector, spray angles matched well with experimental results and discharge coefficients showed approximately 8% differences. On the contrary, discharge coefficients of an open-type swirl injector were similar with experimental result but its spray angles presented around 15% differences. Though the numerical results were not perfectly consistent with experimental data, it is thought that they could be sufficiently used for analyzing spray characteristics, specially which is hard to be measured from experiments. Numerical simulation with different turbulent models was also performed to examine their effects on the numerical results.

• Journal of ILASS-Korea
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• v.10 no.4
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• pp.32-46
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• 2005

The breakup characteristics of liquid sheets formed by the impinging and swirl type injectors were studied as increasing the Weber number (or injection condition) and the ambient gas pressure to 4.0.MPa. In the case of impinging type injector. we compared the changes of breakup lengths between laminar and turbulent sheets. which are formed by the impingement of laminar and turbulent jets. respectively. The results showed that both sheets expand as increasing the injection velocity irrespective of the ambient gas density when the gas based Weber number is low. When the Weber number is high, however, the breakup of turbulent sheet depends on the hydraulic force of jets as well as the aerodynamic force of ambient gas which determines the breakup of laminar sheet. Using the experimental results. we could suggest empirical models on the breakup lengths of laminar and turbulent sheets. In the case of swirl type injector. as $We_l$, and ambient gas density increased, the disturbances on the annular liquid sheet surface were amplified by the increase of the aerodynamic forces. and thus the liquid sheet disintegrated near from the injector exit. Finally, the measured breakup length of swirl type injector according to the ambient gas density and $We_l$, was compared with the result by the linear instability theory. We found that the corrected breakup length relation derived from linear instability theory considering the attenuation of sheet thickness agrees well with our experimental results.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2005.11a
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• pp.335-340
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• 2005

A study on the variation of combustion characteristics by injector geometries was conducted. Coaxial swirl injectors were used. Existence of swirl chamber and variation of a nozzle length become key parameters. Injectors were identified as open, closed and mixed type by existence of swirl chamber. Variation of nozzle length was made extruding the both nozzle along the axis while other design parameters remain the same. A uni-element combustor with ablative material liner and a water cooled nozzle made by oxygen free copper with outer stainless steel casing were used.

• Journal of the korean Society of Automotive Engineers
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• v.13 no.2
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• pp.50-66
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• 1991

There are many factors which influence on the performance of a diesel engine. The piston bowl shape and swirl ratio are important factors to enhance the fuel-air mixing and flame propagation. In this study, calculations of the flow field in the cylinder of the diesel engine were carried out using the CONCHAS-SPRAY code for different bowl shapes and swirl ratios. In the case of constant swirl ratio, vortices which affect fuel-air mixing, evaporation and flame propagation are generated more strongly and consistently in the bowl-piston type combustion chamber than in the flat piston type. With this strong squish effect, injected fuel droplets are widely diffused and rapidly evaporated in the bowl-piston type combustion chamber. Especially a strong squish is developed and large and strong vortices are generated in the edge cutted bowl piston chamber. As the swirl ratio increases, it is found that a large and strong squish and vortices are generated in the combustion chamber and also fuel droplets are diffused into the entire combustion chamber.

• Journal of the Korean Society of Combustion
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• v.19 no.3
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• pp.34-43
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• 2014

The reformer system is a method for hydrogen production from hydrocarbon fuels such as natural gas under high temperature environment($about{\sim}1,000^{\circ}C$). The premixed swirl burner with mixing swirler and combustion swirler designed to deliver fuel cell electric output from 0.5 kW to 1.5 kW. Premixed swirl burner experiments using natural gas and mixture of natural gas and anode off gas were carried out to analyse flame patterns and stability by equivalence ratio respectively. The results show that the stable swirl flame can be established for all cases of fuels type using the premixed swirl burner. The swirl flame had a wide stability region and it showed very low CO(50 ppm) and $NO_x$(20 ppm) emission at different fuel type and various equivalence ratio conditions. The operating range of premixed swirl burner for stable swirl flame is found to exist between equivalence ratio of 0.70 to 0.90 for turn down ratio of 3:1.

• Journal of Advanced Marine Engineering and Technology
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• v.8 no.2
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• pp.88-97
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• 1984

The combustion process and the performance of a diesel engine are considerably affected by the characteristics of fuel spray. It is known that the spray of swirl nozzle for diesel engine injector of small orifice ratio becomes soft spray that has no core, therefore its penetration, one of the characteristics of spray becomes werse inspite of its good dispersion. In this paper, the spray characteristics of variously designed swirl nozzle for diesel injector were investigated by the photographic method. The nozzles, used in this experiment, vary in the diameter of swirl chambers and orifice ratio. From the results of the study, the sprays of this type nozzle of optimum swirl chamber and orifice ratio show that penetration decreased slightly but dispersion and spray volume increased remarcably, compared with unswirled single hole nozzle of the same size. It was suggested as a reason for the results, that the spray of this type swirl nozzle is similar to hard spray, therefore the core of the spray sustains good penetration considerably.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.34 no.4
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• pp.63-69
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• 2006

Experimental tests have been done with swirl injector and helical grain configuration to increase the regression rate of hybrid rocket solid fuel. Two types of injector were designed to evaluate the swirl effect of oxidizer stream on the increase in the regression rate. Results showed Type II injector with swirl number of 3.61 induced the better regression rate than Type I injector. Meanwhile, fuels with two different pitch number of 6 and 100 were used to analyzes the flow characteristics on the enhancement of regression rate. Test with fuels of pitch 6 showed better increase in the regression rate than in the pitch 100 when no swirler was imposed. This is due to the generation of strong turbulences in the oxidizer stream along the pitch 6 configuration. However, the regression rate could be increased further in the fuel with pitch 100 than with pitch 6 when swirl flow was imposed by Type II injector. This result implied that the fuel with pitch 100 could take a role of sustainer of the imposed swirl by swirler II instead of turbulence generator.

• Transactions of the Korean Society of Automotive Engineers
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• v.23 no.5
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• pp.502-507
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• 2015

In this paper, we built a three-dimensional model by applying reverse engineering techniques on targeting the intake port of 2900cc class diesel engine before that three-dimensional design technique is applied. The performance of the intake port is predicted and analysed using the computational flow analysis. Flow Coefficient and Swirl Ratio have been analyzed for two intake port models. One is the intake port for the diesel engine with plunger-type fuel system, and the other is for the diesel engine with CRDI fuel system. Computational result shows that the Flow Coefficient of the intake port with CRDI fuel system is increased upto 10 percentage compared with that with plunger-type. Also, the intake port with plunger-type has high Swirl Ratio at high valve lift, and the intake port with CRDI fuel system has high Swirl Ratio at relatively low valve lift. It is believed that because of high performance of the fuel injector, the intake port with CRDI fuel system is designed for more air amount and not much swirl flow at high valve lift. However, high swirl flow is required at low valve lift for initial fuel and air mixing. The result of this study may be useful for the re-manufacturing industry of automotive parts.