Effect of Primary Zone Operating Condition for Dilution Mixing Behavior in a Gas Turbine

2015 ◽  
Author(s):  
Wei Dai ◽  
Yuzhen Lin ◽  
Quanhong Xu ◽  
Chi Zhang ◽  
Xin Xue
Keyword(s):  
Temperature Distribution ◽  
Gas Turbine ◽  
Numerical Study ◽  
Experimental Results ◽  
Fuel Particle ◽  
Radial Temperature ◽  
Operating Condition ◽  
Fuel Ratio ◽  
Primary Zone ◽  
Exit Temperature

The exit temperature distribution had a great effect on reliability and security in a gas turbine. In this paper, the exit temperature distribution of a small engine reverse-flow combustor with three injectors test module was experimentally obtained to qualitatively analyze the influence of the primary zone operating condition by changing the fuel air ratio at the ambient pressure and temperature condition. Under the nearly identical air condition, there was no obvious difference on the mixing performance with different fuel flow rate. The hot zones occurred at the same position of the combustor exit section, and the temperature declined in the radial direction from the center. It could be seen that the radial temperature profiles in FAR of 0.022–0.03 were almost same. Malvern experimental results showed that the air fuel ratio of swirler cup ranges from 5 to 40 and the droplet distribution index n could not be increased or decreased by the ratio at different air pressure drop. The air fuel ratio of combustor swirl cup had reached more than 5 which fuel particle had been nearly stable and not got some variation by changing the fuel mass rate. As a result, the increase of fuel air ratio had no impact on fuel atomization uniformity in combustor dome. The fuel had been completely atomized when the combustor fuel air ratio ranged from 0.022 to 0.03, and its impact on the droplet size and uniformity of fuel could be neglected. With the uniform fuel spray, a numerical study of the whole combustor had been made to analyze the strong relation between swirl flow and jets of primary holes and dilution holes. The dilution jets had a strong effect on quenching flame and temperature dilution. Along the combustor flow direction, the temperature difference became less and less obvious, the addition of fuel would enhance the combustion intensity mainly in combustion zone, but with an effect of dilution jet, the temperature distributions had little deviation when increasing the fuel air ratio. And it showed a same phenomenon that different fuel air ratio would make the same exit temperature distribution which was found to be in line with the experimental results. In a word, for the primary zone operating condition in the combustor, it almost had no effect on the temperature distribution at the exit of the combustor by changing the fuel air ratio from 0.022 to 0.030 in primary zone at normal pressure and temperature condition.

scholarly journals A Method for Determining the Main Requirements of Outlet Gas Temperature Profile of Marine Gas Turbine Combustors

1982 ◽  
Author(s):  
Tang Chian-ti
Keyword(s):  
Temperature Distribution ◽  
Temperature Profile ◽  
Gas Turbine ◽  
Guide Vane ◽  
Safety Margin ◽  
Gas Temperature ◽  
Distribution Factor ◽  
Radial Temperature ◽  
Blade Height ◽  
Blade Cooling

Taking account of the marine gas turbine operation features, the author has chosen the hot corrosion peak temperature of materials as the guide vane material limiting temperature while evaluating the overall temperature distribution factor. Along with the blade cooling effectiveness a safety margin factor has been introduced during its evaluation. The gas temperature distribution along blade height is assumed to satisfy the condition that approximately equal safety factor in respect of strength prevails along blade height. Once the gas radial temperature profile becomes known, the radial temperature distribution factor can be readily determined.

Development of a Natural Gas-Fired, Ultra-Low NOx Can Combustor for an 800 KW Gas Turbine

1991 ◽  
Author(s):  
K. O. Smith ◽  
A. C. Holsapple ◽  
H. K. Mak ◽  
L. Watkins
Keyword(s):  
Natural Gas ◽  
Gas Turbine ◽  
Premixed Combustion ◽  
Experimental Results ◽  
Nox Emissions ◽  
Variable Geometry ◽  
Lean Premixed Combustion ◽  
Full Load ◽  
Primary Zone ◽  
Lean Premixed

The experimental results from the rig testing of an ultra-low NOx, natural gas-fired combustor for an 800 to 1000 kw gas turbine are presented. The combustor employed lean-premixed combustion to reduce NOx emissions and variable geometry to extend the range over which low emissions were obtained. Testing was conducted using natural gas and methanol. Testing at combustor pressures up to 6 atmospheres showed that ultra-low NOx emissions could be achieved from full load down to approximately 70% load through the combination of lean-premixed combustion and variable primary zone airflow.

scholarly journals Experimental and numerical study of the effect of coil structure on induction nitriding temperature field

2020 ◽  
Vol 12 (7) ◽  
pp. 168781402093848
Author(s):  
Kangjie Song ◽  
Jing Guan ◽  
Kunmao Li ◽  
Jing Liu
Keyword(s):  
Temperature Field ◽  
Temperature Distribution ◽  
Induction Heating ◽  
Current Density ◽  
Numerical Study ◽  
Radial Temperature ◽  
Current Frequency ◽  
Variable Pitch ◽  
Variable Radius ◽  
Heating Efficiency

The axial and radial temperature distributions of an induction heating workpiece considerably impact the subsequent nitriding process. To obtain a satisfactory temperature distribution, an equal pitch coil, a variable pitch coil, and a variable radius coil were designed. Furthermore, an induction heating model that exhibits electromagnetic and temperature field coupling was established; thus, the effects of the current density and frequency on the heating efficiency and temperature distribution of the workpiece were analyzed and compared. In addition, an induction heating experiment was conducted to verify the model. According to the numerical results, the variable radius coil can reduce the axial temperature difference in comparison with equal pitch coil and variable pitch coil. Hence, the workpiece heated using the variable radius coil can achieve a better temperature distribution when compared with those heated by the equal pitch coil and variable pitch coil, with appropriate current density and current frequency values.

Numerical Simulation for the Preliminary Design of Fuel Flexible Stationary Gas Turbine Combustors Using Conventional and Alternative Fuels

2012 ◽  
Author(s):  
Washington Orlando Irrazabal Bohorquez ◽  
João Roberto Barbosa ◽  
Rob Johan Maria Bastiaans ◽  
Philip de Goey
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Alternative Fuels ◽  
High Efficiency ◽  
Numerical Study ◽  
Operating Conditions ◽  
Pollutant Emissions ◽  
Gas Turbine Combustor ◽  
Primary Zone

Currently, high efficiency and low emissions are most important requisites for the design of modern gas turbines due to the strong environmental restrictions around the world. In the past years, alternative fuels have been considered for application in industrial gas turbines. Therefore, combustor performance, pollutant emissions and the ability to burn several fuels became of much concern and high priority has been given to the combustor design. This paper describes a methodology focused on the design of stationary gas turbines combustion chambers with the ability to efficiently burn conventional and alternative fuels. A simplified methodology is used for the calculations of the equilibrium temperature and chemical species in the primary zone of a gas turbine combustor. Direct fuel injection and diffusion flames, together with numerical methods like Newton-Raphson, LU Factorization and Lagrange Polynomials, are used for the calculations. Diesel, ethanol and methanol fuels were chosen for the numerical study. A computer code sequentially calculates the main geometry of the combustor. From the numerical simulation it is concluded that the basic gas turbine combustor geometry, for some operating conditions and burning diesel, ethanol or methanol, are of similar sizes, because the development of aerodynamic characteristics predominate over the thermochemical properties. It is worth to note that the type of fuel has a marked effect on the stability and combustion advancement in the combustor. This can be seen when the primary zone is analyzed under a steady-state operating condition. At full power, the pressure is 1.8 MPa and the temperature 1,000 K at the combustor inlet. Then, the equivalence ratios in the primary zone are 1.3933 (diesel), 1.4352 (ethanol) and 1.3977 (methanol) and the equilibrium temperatures for the same operating conditions are 2,809 K (diesel), 2,754 K (ethanol) and 2,702 K (methanol). This means that the combustor can reach similar flame stability conditions, whereas the combustion efficiency will require richer fuel/air mixtures of ethanol or methanol are burnt instead of diesel. Another important result from the numerical study is that the concentration of the main pollutants (CO, CO2, NO, NO2) is reduced when ethanol or methanol are burnt, in place of diesel.

Numerical Study of NOx Emissions in RQL Gas Turbine Combustor

2012 ◽  
Vol 510 ◽  
pp. 545-548
Author(s):  
Liang Yu ◽  
Shu Sheng Yuan ◽  
Zhi Bing Pang ◽  
Yun Liang Wang
Keyword(s):  
Flow Field ◽  
Gas Turbine ◽  
Numerical Study ◽  
Simple Algorithm ◽  
Wall Region ◽  
Gas Turbine Combustor ◽  
Mixing Processes ◽  
Finite Difference Equations ◽  
High Temperature Area ◽  
Exit Temperature

RNG (Renormalization Group) k-ε turbulent model was applied to the numerical simulation of turbulent mixing processes in the RQL gas turbine combustor, and SIMPLE algorithm was used to solve the finite difference equations. The calculated conclusions were used to analyze temperature distribution of the mixed flow field and near-wall region of the flow field, and then discuss the NOx emissions. The results show that the effect of the injector zone geometry and the jet to crossflow momentum flux ratios on the NOx emissions is obvious. The reasonable control of jet is beneficial to reduce the local high temperature area and is able to improve the distribution of the exit temperature. And then achieve the goal of reducing the environmental pollution.

Numerical Simulation as Design Optimization Tool for Gas Turbine Combustion Chambers

2010 ◽  
Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Saurabh B. Dikshit
Keyword(s):  
Numerical Simulation ◽  
Temperature Distribution ◽  
Combustion Chamber ◽  
Design Optimization ◽  
Gas Turbine ◽  
Flow Patterns ◽  
Intermediate Zone ◽  
Experimental Investigations ◽  
Combustion Chambers ◽  
Primary Zone

In present study an attempt has been made through CFD approach using CFX 11 to analyze the flow patterns within the combustion liner and through different air admission holes, namely, primary zone, intermediate zone, dilution zone and wall cooling, and from these the temperature distribution in the liner and at walls as well as the temperature quality at the exit of the combustion chamber are predicted. The design optimization is carried out using the CFD results with validation using experimental investigations.

Numerical Study of Spray Parametric Effects on Gas Turbine Combustion Performance

1999 ◽  
Author(s):  
K. Su ◽  
C. Q. Zhou
Keyword(s):  
Temperature Distribution ◽  
Gas Turbine ◽  
Numerical Study ◽  
Combustion Efficiency ◽  
Fuel Spray ◽  
Injection Velocity ◽  
Fuel Sprays ◽  
Combustion Performance ◽  
Mean Diameter ◽  
Spray Distribution

Abstract A numerical study was conducted to determine the effects of fuel spray characteristics on the gas turbine combustion performance including the combustion efficiency and the overall temperature distribution factor (OTDF) at the exit of the combustor using the KIVA-3V code. A model of a typical annular combustor was used in the computations. Operating conditions were varied with inlet pressure from 0.1 to 1.2 MPa, inlet temperature from 400 to 650 K, and air fuel ratio from 0.015 to 0.024. A log-normal spray distribution was assumed to simulate a real fuel spray distribution at injection. The droplet mean diameter as well as injection velocity and angle were independently varied to distinguish the separate effects of variables involved. Flow fields and temperature distributions in the combustor were analyzed. The results reasonably agreed with those from a semi-empirical approach. It is found that the overall temperature distribution deteriorates as the Sauter mean diameter of fuel spray increases. There is an optimum range of the Sauter mean diameters for the efficient combustion of fuel sprays. The overall temperature distribution is improved as the injection velocity of fuel sprays increases, but the combustion efficiency does not change much with it. It appears that the KIVA-3V code can be used to guide the design and improvement of the gas turbine combustor.

scholarly journals Numerical Heat Transfer Analysis of an Innovative Gas Turbine Combustor: Coupled Study of Radiation and Cooling in the Upper Part of the Liner

2005 ◽  
Author(s):  
A. Andreini ◽  
A. Bacci ◽  
C. Carcasci ◽  
B. Facchini ◽  
A. Asti ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Gas Turbine ◽  
Cooling System ◽  
Numerical Study ◽  
Radiative Properties ◽  
Heat Transfer Analysis ◽  
Transfer Model ◽  
Cold Side ◽  
Additional Tool

A numerical study of a single can combustor for the GE10 heavy-duty gas turbine, which is being developed at GE-Energy (Oil & Gas), is performed using the STAR-CD CFD package. The topic of the present study is the analysis of the cooling system of the combustor liner’s upper part, named “cap”. The study was developed in three steps, using two different computational models. As first model, the flow field and the temperature distribution inside the chamber were determined by meshing the inner part of the liner. As second model, the impingement cooling system of the cold side of the cap was meshed to evaluate heat transfer distribution. For the reactive calculations, a closure of the BML (Bray-Moss-Libby) approach based on Kolmogorov-Petrovskii-Piskunov theorem was used. The model was implemented in the STAR-CD code using its user coding features. Then the radiative thermal load on the liner walls was evaluated by means of the STAR-CD-native Discrete Transfer model. The selection of the radiative properties of the flame was performed using a correlation procedure involving the total emissivity of the gas, the mean beam length and the gas temperature. The estimated heat flux on the cap was finally used as boundary condition for the calculation of the cooling system, consisting of 68 staggered impingement jet lines on the cold side of the cap. The resulting temperature distribution shows a good agreement with the experimental values measured by thermocouples. The results confirm the validity of the implemented procedure, and point out the importance of a full CFD computation as an additional tool to support classic correlation design procedures.

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