• Journal of the Korean Society of Propulsion Engineers
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• v.25 no.2
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• pp.12-23
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• 2021

In this study, the combustion instability characteristics of low-swirl injector and high-swirl injector is compared by model gas turbine combustor. To compare of unstable behavior in high-swirl injector and low-swirl injector, we performed lots of measurement of combustion instability, with variable of equivalence ratio, combustor length and injector type. The results shown that longitudinal instability occur dominantly in model gas turbine combustor. In addition, it was found that high-swirl injector has more wide range of unstable regime than low-swirl injector. The blockage ratio what one of a parameter in low-swirl injector has not much effected in aspects of overall combustor behavior. Also, revealed that combustion instability occurred in the same combustor length has same properties, regardless of the injector type.

• Journal of the Korean Society of Combustion
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• v.6 no.2
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• pp.29-35
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• 2001

Unsteady numerical study has been conducted on combustion dynamics of a lean-premixed swirl-stabilized gas turbine swirl injector. A three-dimensional computation method utilizing the message passing interface (MPI) parallel architecture, large eddy simulation(LES), and proper orthogonal decomposition (POD) technique was applied. The unsteady turbulent flame dynamics are simulated so that the turbulent flame structure can be characterized in detail. It was observed that some fuel lumps escape from the primary combustion zone, and move downstream and consequently produce hot spots. Those flame dynamics coincides with experimental data. In addition, basis modes of the unsteady turbulent flame are characterized using proper orthogonal decomposition (POD) analysis. The flame structure based on odd basis modes is apparently larger than that of even ones. The flame structure can be extracted from the summation of the basis modes and eigenvectors at any moment.

• 한국연소학회:학술대회논문집
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• 2005.10a
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• pp.287-293
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• 2005

Most of all combustion system has combustion instability. It is a serious problem in combustion system. Unstable injection is one of the source of combustion instability. The experimental investigation of spray characteristics for simplex swirl injector were conducted experimentally. Two kerosene based fuels were chosen as the atomizing fluid. As the major operating parameters, fuel temperature and injection pressure were chosen, and varied in the range from 253 K to 293 K and from 0.2 MPa to 1.0 MPa, respectively. Direct spray images and mean diameter were measured for the various combination of operating parameters in the flow field. The results of present study show that the injection pressure and spray cone angle are fluctuated at specific conditions while it is continuous steady injection. As the fuel temperature changes continuously, spray cone angle varies discontinuously through the region of injection instability.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.16 no.4
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• pp.13-21
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• 2007

This paper presents characteristics of steady flow by variation of a combustion chamber and an intake port. Gas flow field inside a combustion chamber is the important factor in improving combustion stability and reduction of emission level. The flow characteristics such as flow coefficient, tumble ratio and swirl ratio are measured by the steady flow rig test with an impulse meter in this study. In the measuring, the valve lifts are varied between 1mm to 10mm. The three combustion chambers and two intake ports were applied to the steady flow apparatus in order to investigate the effect of swirl and tumble on the in-cylinder flow. As a result, tumble ratio were found to be different by variation of the combustion chambers and the intake ports. The data from the present study can be applied to design of a similar engine as basic data.

• 한국연소학회:학술대회논문집
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• 2012.04a
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• pp.195-196
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• 2012

This paper describes combustion tuning methodology of double-swirl gas turbine combustor using six sigma tools. This methodology is consist of five steps-Define, Identify, Design, Optimize and Verify (DIDOV). First, the NOx reduction target was defined in the step design; second, the current status of the plant was diagnosed in the step of identify; third, the vital few control parameters to achieve the defined target were determined by analyzing the correlation between the control parameters and NOx emissions in the step of design; fourth, the optimum condition was derived from one of the six sigma tools in the step of optimize; finally, the optimum condition was verified by applying the condition to the gas turbine combustor in the step of verify. As a result of the suggested method, averaged NOx emissions were reduced by more than 70% and the standard deviation was improved by more than 60%. Thus, this methodology can be attributed to the efficient reduction of NOx emission with saving combustion tuning time.

• Journal of the korean Society of Automotive Engineers
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• v.10 no.5
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• pp.42-53
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• 1988

The effects of ignition position on combustion in a chamber with swirl flow were investigated by use of hot wire anemometer, high speed schlieren photography, and chamber pressure measurement. In experiments, the closed-constant volume combustion chamber was used, and the swirl was formed unsteadily by suction of external fluid after reducing pressure in the chamber. Results show that the effect of ignition position on combustion depends on the flow state and the flame propagation distance corresponding to each ignition position. Also, the effect of combustion promoting increases as an ignition position moves from the center of chamber to the outside, but maximum burning pressure was obtained at the position that is the shortest flame propagation distance.

• Proceedings of the KSME Conference
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• 2001.06d
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• pp.858-863
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• 2001

In this paper, the test and result of flow and combustion for 21AFR lean fuel models are described. The necessity to develop the low emission combustor has been issued from the concern on the increase of green house and the destruction of ozone layer. To evaluate the flow and combustion performance of new designed 21AFR lean modules, the hydraulic tests in stereo lithographic airflows models, the low pressure combustion tests in three injectors model for weak extinction and ignition and the high pressure combustion tests in single sector for NOx, SAE and efficiency are performed. The low pressure tests reveal that the governing parameters in weak extinction and ignition at atmospheric condition are prefilmer length, swirl flow rotation direction, secondary swirl angle and flow split. As a results of combustion test at high pressure, the efficiency and smoke level are satisfied with performance targets, but EINOx of 17.8 is higher than target value of 13.1. The high pressure tests show that the main parameters influenced on NOx are primary swirl angle, swirl flow rotation direction, heatshield exit angle and liner mixing hole location.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.8
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• pp.1132-1137
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• 2002

In this paper, the test results of the combustion for 2 IAFR lean fuel models are described. The need for the low emission combustor has been issued from the concern on the increase of green house and the destruction of ozone layer. To evaluate the flow and combustion performance of newly designed 21AFR lean modules, the hydraulic tests in stereolithographic airflows models, the low pressure combustion tests in three injectors model for weak extinction and ignition and the high pressure combustion tests in single sector for NOx, SAE and efficiency are performed. The low pressure tests reveal that the governing parameters in weak extinction and ignition at atmospheric condition are prefilmer length, swirl flow rotation direction, secondary swirl angle and flow split. As a result of combustion test at high pressure, the efficiency and smoke level are satisfied with performance targets, but EINOx of 17.8 is higher than target value of 13.1 The high pressure tests show that the main parameters influenced on NOx are primary swirl angle, swirl flow rotation direction, heatshield exit angle and liner mixing hole location.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.26 no.3
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• pp.458-464
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• 2002

Recently, many researches have been performed to improve performances of the combustion and emission in the D.I.Diesel engine. Especially reduction of the soot formation in tole combustion chamber is the essential to acquire the improvement of the emission performance. These emission of the diesel combustion is effected by the characteristics of air-fuel mixing. Thus, in this study, the distribution of soot in the diesel combustion is measured by LII(laser induced incandescence) and LIS(Laser induced scattering) method. From this experimental results, it is confirmed that the swirl flow intensified by SCV(swirl control valve) is effective on the reduction of soot in the combustion chamber.

• Journal of ILASS-Korea
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• v.19 no.2
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• pp.75-81
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• 2014

Swirl flow in the gun type burner has a decisive effect on the stabilization of the flame, improvement of the combustion efficiency, and also a reduction of NOx. This swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed nozzle adapter, spark gap ignitor, and spinner. These inner components change the air flow behavior passing through air tube. Meanwhile, turbulent characteristics of this air flow are important to understand the combustion phenomena in the gun type burner, because the mixture of fuel and air are depended on. However, nearly all of the studies have been analyzed the turbulent flow of simplified combustion formation without the inner devices. So, this study conducted the measurement using by hot-wire anemometer and analyzed turbulent flow characteristics of the swirl flow discharged from the air tube with inner devices. Turbulence characteristics come up in this study were turbulence intensity, kinetic energy and shear stress of the air flow with the change of the distance of axial direction from the exit of the air tube.