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.

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.

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.

Technological Trend of Aircraft Gas Turbines and its Effect on the Development for Ship Propulsion Plants

1970 ◽  
Author(s):  
N. K. H. Scholz
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Pressure Ratio ◽  
Gas Turbine Engine ◽  
Design Parameters ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Compression Pressure ◽  
Turbine Engine ◽  
Ship Propulsion

The effect of the main design parameters of the aero gas turbine engine cycle, namely combustion temperature and compression pressure ratio, on the specific performance values is discussed. The resulting development trend has been of essential influence on the technology. Relevant approaches are outlined. The efforts relating to weight and manufacturing expense are also indicated. In the design of aero gas turbine engines increasing consideration is given to the specific flight mission requirements, such as for instance by the introduction of the by-pass principle. Therefore direct application of aero gas turbine engines for ship propulsion without considerable modifications, as has been practiced in the past, is not considered very promising for the future. Nevertheless, there are possibilities to take advantage of aero gas turbine engine developments for ship propulsion systems. Appropriate approaches are discussed. With the experience obtained from aero gas turbine engines that will enter service in the early seventies it should be possible to develop marine gas turbine engines achieving consumptions and lifes that are competitive with those of advanced diesel units.

Prediction of CO Emission Index for Aviation Gas Turbine Combustor Using Flamelet Generated Manifold Combustion Model

2021 ◽  
Author(s):  
Saurabh Patwardhan ◽  
Pravin Nakod ◽  
Stefano Orsino ◽  
Rakesh Yadav ◽  
Fang Xu ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Liquid Fuel ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Combustion Model ◽  
Gas Turbine Engines ◽  
Gas Turbine Combustor ◽  
Flamelet Generated Manifold ◽  
Emission Index ◽  
Co Emission

Abstract Carbon monoxide (CO) has been identified as one of the regulated pollutants and gas turbine manufacturers target to reduce the CO emission from their gas turbine engines. CO forms primarily when carbonous fuels are not burnt completely, or products of combustion are quenched before completing the combustion. Numerical simulations are effective tools that allow a better understanding of the mechanisms of CO formation in gas turbine engines and are useful in evaluating the effect of different parameters like swirl, fuel atomization, mixing etc. on the overall CO emission for different engine conditions like idle, cruise, approach and take off. In this paper, a thorough assessment of flamelet generated manifold (FGM) combustion model is carried out to predict the qualitative variation and magnitude of CO emission index with the different configurations of a Honeywell test combustor operating with liquid fuel under idle condition, which is the more critical engine condition for CO emission. The different designs of the test combustor are configured in such a way that they yield different levels of CO and hence are ideal to test the accuracy of the combustion model. Large eddy simulation (LES) method is used for capturing the turbulence accurately along with the FGM combustion model that is computationally economical compared to the detailed/reduced chemistry modeling using finite rate combustion model. Liquid fuel spray breakup is modeled using stochastic secondary droplet (SSD) model. Four different configurations of the aviation gas turbine combustor are studied in this work referring to earlier work by Xu et al. [1]. It is shown that the FGM model can predict CO trends accurately. The other global parameters like exit temperature, NOx emissions, pattern factor also show reasonable agreement with the test data. The sensitivity of the CO prediction to the liquid fuel droplet breakup model parameters is also studied in this work. Although the trend of CO variation is captured for different values of breakup parameters, the absolute magnitude of CO emission index differs significantly with the change in the values of breakup parameters suggesting that the spray has a larger impact on the quantitative prediction of CO emission. An accurate prediction of CO trends at idle conditions using FGM model extends the applicability of FGM model to predict different engine operating conditions for different performance criteria accurately.

A Comparison of Two Methods for Predicting Emissions From Aircraft Gas Turbine Combustors

2007 ◽  
Author(s):  
Douglas L. Allaire ◽  
Ian A. Waitz ◽  
Karen E. Willcox
Keyword(s):  
Gas Turbine ◽  
Empirical Method ◽  
Design Parameters ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Predictive Capability ◽  
Gas Turbine Combustors ◽  
Emissions Modeling ◽  
Design Tradeoffs ◽  
High Level

This paper discusses the development and comparison of two emissions modeling methods for predicting NOx and CO emissions from aircraft gas turbine combustors. We compare an empirical and a physics-based approach. The objective is to assess the strengths and weaknesses of the methods for predicting the emissions of current and potential future gas turbine engines for the purpose of assessing design tradeoffs and interdependencies in a policy-making setting. The empirical method is based on a P3-T3 approach using polynomial fits to certification data. The physics-based method is developed using high-level combustor design parameters and ideal reactors. The predictive capability of each method is assessed by comparing model estimates of NOx and CO emissions to certification data from three different industry combustors.

Experimental Study of Hydraulic Flip Phenomenon inside Diesel Nozzles Using Diesel and Biodiesel

2014 ◽  
Vol 945-949 ◽  
pp. 940-943 ◽  
Author(s):  
Zhuang Shao ◽  
Zhi Xia He ◽  
Zhi Wei Zhou ◽  
Xi Cheng Tao
Keyword(s):  
Discharge Coefficient ◽  
Cone Angle ◽  
Great Influence ◽  
Flow Characteristics ◽  
Injection Pressure ◽  
Cavitating Flow ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
The Difference ◽  
Biodiesel Fuels

As cavitation inside diesel nozzles can improve the spray characteristics, it has long been a hot issue. And together with the increasing attention of biodiesel, it is essential to identify the difference of cavitating flow characteristics between diesel and biodiesel. What’s more, the hydraulic flip phenomenon and cavitating flow with decreasing injection pressure hasn’t been studied. Based on this, cavitating flow inside transparent nozzles of diesel and biodiesel fuels with increasing and decreasing injection pressure was investigated in this paper. Experimental results showed that are quite different from the disappearance of it and it is harder to disappear. Biodiesel and longer nozzle orifices were hard for the hydraulic flip phenomenon to occur, and the disappearance of hydraulic flip phenomenon has great influence on the spray cone angle and the discharge coefficient.

Empirical and Semi-Empirical Correlation of Emissions Data From Modern Turbopropulsion Gas Turbine Engines

1996 ◽  
Author(s):  
Allen M. Danis ◽  
Byron A. Pritchard ◽  
Hukam C. Mongia
Keyword(s):  
Gas Turbine ◽  
Empirical Correlation ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Reactor Modeling ◽  
Annular Combustor ◽  
Unburned Hydrocarbons ◽  
Semi Empirical ◽  
Operating Points ◽  
Unique Relationship

The engine certification emissions data from a CFM56 single-annular combustor (SAC), the CFM56 dual-annular combustor (DAC), the CF6-80C SAC and the CF6-80C SAC low-emissions configuration (LEC) were used to show the following: (1) NOxEI can be correlated as a function of P3 and T3. (2) There is a unique relationship between NOx, CO and unburned hydrocarbons (HC). (3) NOx, CO and HC for engine operating points can be predicted reasonably well through “single reactor” modeling. However, the resulting NOx/CO/HC relationship is not as well predicted indicating need for further improving the semiempirical methodology.

Computational assessment of performance parameters of an aero gas turbine combustor for full flight envelope operation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Saroj Kumar Muduli ◽  
R. K. Mishra ◽  
Purna Chandra Mishra
Keyword(s):  
Gas Turbine ◽  
Cone Angle ◽  
Performance Estimation ◽  
Temperature Pattern ◽  
Operating Pressure ◽  
Performance Parameters ◽  
Gas Turbine Combustor ◽  
Spray Cone Angle ◽  
Spray Cone ◽  
Wide Range

Abstract This paper presents the computational study carried out on an aero gas turbine combustor to assess important performance parameters. The CFD results are compared with experimental dataobtained from the full scale combustor tested at ground test stand simulating various operational conditions. The CFD predictions have agreed very well with the experimental data. The model is then extended to predict combustor exit temperature pattern factors, pressure loss, and combustion efficiency and exhaust gas constituents over a wide range of operating pressure and temperature conditions. The paper also presents the studies carried out on the effect of atomizer spray cone angle, particle size and fuel flow variations expected due to manufacturing tolerances in various flow passages as well as due to operational degradations on temperature pattern factors. The pattern factors are also analyzed on cold and hot day environment. The radial pattern factor (RPF) at mid height is found to increase as altitude increases from sea level to 12 km. Spray cone angle is found to have a predominant effect on temperature non-uniformity at exit, lower cone angle increasing both radial and circumferential pattern factors. The findings of this study are valuable inputs for engine performance estimation.

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