Effect of Downstream Contraction on Liner Heat Transfer in a Gas Turbine Combustor Swirl Flow

2015 ◽  
Author(s):  
Sandeep Kedukodi ◽  
Srinath Ekkad
Keyword(s):  
Heat Transfer ◽  
Gas Turbine ◽  
Swirl Flow ◽  
Reacting Flow ◽  
Flow Profile ◽  
Flow Conditions ◽  
Gas Turbine Combustor ◽  
Inlet Flow ◽  
Flow Simulations ◽  
Accelerated Flow

Established numerical approaches for performing detailed flow analysis happens to be an effective tool for industry based applied research. In the present study, computations are performed on multiple gas turbine combustor geometries for turbulent, non-reactive and reactive swirling flow conditions for an industrial swirler. The purpose of this study is to identify the location of peak convective heat transfer along the combustor liner under swirling inlet flow conditions and to investigate the influence of combustor geometry on the flow field. Instead of modeling the actual swirler along with the combustor, an inlet swirl flow profile is applied at the inlet boundary based on previous literature. Initially, the computed results are validated against available experimental data for an inlet Reynolds number flow of 50000 using a 2D axi-symmetric flow domain for non-reacting conditions. A constant heat flux on the liner is applied for the study. Two turbulence models (RNG k-ε and k-ω SST) are utilized for the analysis based on its capability to simulate swirling flows. It is found that both models predict the peak liner heat transfer location similar to experiments. However, k-ε RNG model predicts heat transfer magnitude much closer to the experimental values except displaying an additional peak whereas k-ω model predicts only one peak but tends to over-predict in magnitude. Since the overall characteristic liner heat transfer trend is captured well by the latter one, it is chosen for future computations. A 3D sector (30°) model results also show similar trends as 2D studies. Simulations are then extended to 3 different combustors (Case 1: full cylinder and Case 2 and 3: cylinders with downstream contractions having reduced exit areas) by adopting the same methodology for same inlet flow conditions. Non-reacting simulations predict that the peak heat transfer location is marginally reduced by the downstream contraction of the combustor. However the peak location shifts towards downstream due to the presence of accelerated flow. Reacting flow simulations are performed with Flamelet Generation Manifold (FGM) model for simulating premixed combustion for the same inlet flow conditions as above. It is observed that Case 3 predicts a threefold increase in the exit flow velocity in comparison to non-reacting flow simulations. The liner heat transfer predictions show that both geometries predict similar peak temperatures. However, only one fourth of the initial liner length experiences peak temperature for Case 1 whereas the latter continues to feel the peak till the end. This behavior of Case 3 can be attributed to rapid convection of high temperature products downstream due to the prevailing accelerated flow.

Flow Field and Wall Temperature Measurements for Reacting Flow in a Lean Premixed Swirl Stabilized Can Combustor

2018 ◽  
Vol 140 (9) ◽  
Author(s):  
Suhyeon Park ◽  
David Gomez-Ramirez ◽  
Siddhartha Gadiraju ◽  
Sandeep Kedukodi ◽  
Srinath V. Ekkad ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Gas Turbine ◽  
Swirling Flow ◽  
Single Case ◽  
Operating Conditions ◽  
Reacting Flow ◽  
Flow Conditions ◽  
Gas Turbine Combustor ◽  
Lean Premixed

In this study, we provide detailed wall heat flux measurements and flow details for reacting flow conditions in a model combustor. Heat transfer measurements inside a gas turbine combustor provide one of the most serious challenges for gas turbine researchers. Gas turbine combustor improvements require accurate measurement and prediction of reacting flows. Flow and heat transfer measurements inside combustors under reacting flow conditions remain a challenge. The mechanisms of thermal energy transfer must be investigated by studying the flow characteristics and associated heat load. This paper experimentally investigates the effects of combustor operating conditions on the reacting flow in an optical single can combustor. The swirling flow was generated by an industrial lean premixed, axial swirl fuel nozzle. Planar particle image velocimetry (PIV) data were analyzed to understand the characteristics of the flow field. Liner surface temperatures were measured in reacting condition with an infrared camera for a single case. Experiments were conducted at Reynolds numbers ranging between 50,000 and 110,000 (with respect to the nozzle diameter, DN); equivalence ratios between 0.55 and 0.78; and pilot fuel split ratios of 0 to 6%. Characterizing the impingement location on the liner, and the turbulent kinetic energy (TKE) distribution were a fundamental part of the investigation. Self-similar characteristics were observed at different reacting conditions. Swirling exit flow from the nozzle was found to be unaffected by the operating conditions with little effect on the liner. Comparison between reacting and nonreacting flows (NR) yielded very interesting and striking differences.

3D RANS Simulation of Turbulent Flow and Combustion in a 5 MW Reverse-Flow Type Gas Turbine Combustor

2010 ◽  
Vol 132 (11) ◽  
Author(s):  
Daero Joung ◽  
Kang Y. Huh
Keyword(s):  
Turbulent Flow ◽  
Gas Turbine ◽  
Reverse Flow ◽  
Measurement Data ◽  
Swirl Flow ◽  
Reacting Flow ◽  
Mean Flow ◽  
Gas Turbine Combustor ◽  
Rans Simulation ◽  
Combustion Models

This study is concerned with 3D RANS simulation of turbulent flow and combustion in a 5 MW commercial gas turbine combustor. The combustor under consideration is a reverse flow, dry low NOx type, in which methane and air are partially mixed inside swirl vanes. We evaluated different turbulent combustion models to provide insights into mixing, temperature distribution, and emission in the combustor. Validation is performed for the models in STAR-CCM+ against the measurement data for a simple swirl flame (http://public.ca.sandia.gov/TNF/swirlflames.html). The standard k-ε model with enhanced wall treatment is employed to model turbulent swirl flow, whereas eddy break-up (EBU), presumed probability density function laminar flamelet model, and partially premixed coherent flame model (PCFM) are tried for reacting flow in the combustor. Independent simulations are carried out for the main and pilot nozzles to avoid flashback and to provide realistic inflow boundary conditions for the combustor. Geometrical details such as air swirlers, vane passages, and liner holes are all taken into account. Tested combustion models show similar downstream distributions of the mean flow and temperature, while EBU and PCFM show a lifted flame with stronger effects of swirl due to limited increase in axial momentum by expansion.

Gas Turbine Combustor Rig Development and Initial Observations at Cold and Reacting Flow Conditions

2016 ◽  
Author(s):  
David Gomez-Ramirez ◽  
Sandeep Kedukodi ◽  
Siddhartha Gadiraju ◽  
Srinath V. Ekkad ◽  
Hee-Koo Moon ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Flow Field ◽  
Gas Turbine ◽  
Primary Objective ◽  
Reacting Flow ◽  
Fuel Injector ◽  
Imaging Data ◽  
Test Rig ◽  
Gas Turbine Combustor ◽  
Inlet Conditions

The present paper describes the first phase of the design and development of a realistic, high-pressure, full-scale research gas turbine combustor at Virginia Tech. The final test rig will be capable of operating at inlet temperatures of 650 K, pressures up to 9.28 Bar (120 psig), maximum air inlet flow rates of 1.27 kg/s (2.8 lbm/s), and allow for variations in the geometry of the combustor model. The first phase consists of a low-pressure (atmospheric) optical combustor for heat transfer and flow-field measurements at isothermal and reacting conditions. The combustor model is equipped with an industrial low emission fuel injector from Solar Turbines Incorporated, used in their land based gas turbine Taurus-60. The primary objective of the developed rig is to provide additional insight into the heat transfer processes that occur within gas turbine combustors, primarily the convective component, which has not been characterized. A future phase of the test rig development will incorporate a pressure vessel that will allow for the operation of the combustor simulator at higher pressures. In the present publication, the design methodology and considerations, as well as the challenges encountered during the design of the first phase of the simulator are briefly discussed. An overview is given on the design of the instrumentation and process piping surrounding the test rig, including ASME codes followed as well as the instrumentation and equipment selected. A detailed description of the test section design is given, highlighting the design for high temperature operation. As an example of the capabilities of the rig, representative measurements are presented. Characterization of the isothermal flow field using planar Particle Image Velocimetry (PIV) at a Reynolds number of 50 000 was performed and compared with flame imaging data at the same inlet conditions operating at an equivalence ratio of 0.7. The data suggests that the flame location follows the maximum turbulent kinetic energy as measured in the isothermal field. Representative data from the computational efforts are also presented and compared with the experimental measurements. Future work will expand on both reacting and isothermal PIV and heat transfer measurements, as well as computational validations.

Numerical Simulation of Non-Reacting and Reacting Flows in a 5MW Commercial Gas Turbine Combustor

2009 ◽  
Author(s):  
Daero Jeong ◽  
Kang Y. Huh
Keyword(s):  
Numerical Simulation ◽  
Gas Turbine ◽  
Measurement Data ◽  
Turbulence Models ◽  
Swirl Flow ◽  
Reacting Flows ◽  
Reacting Flow ◽  
Mean Flow ◽  
Gas Turbine Combustor ◽  
Swirl Flame

This study is concerned with numerical simulation of a simple swirl flame and a 5MW commercial gas turbine combustor both operating on methane/air. Validation is performed for turbulent flow and combustion models against some measurement data (http://public.ca.sandia.gov/TNF/swirlflames.html). Evaluation is performed for the standard k-e and the realizable k-e models in the nonreacting swirl flow and the EBU (eddy breakup) and the PPDF (presumed probability density function) models in the reacting flow of the 5 MW commercial combustor. Independent simulations are carried out for the main and pilot nozzles to avoid flashback and to provide realistic inflow boundary conditions for the combustor. Important geometrical details such as air swirlers, vane passages and liner holes are taken into account. Different turbulence models result in similar flow patterns with varying sizes of the recirculation pockets in the central region and at the outside corner. The EBU and the PPDF models show similar downstream distributions of mean flow and temperature, while the EBU shows a lifted flame with a stronger effect of swirl due to limited increase of axial momentum by volume expansion near the nozzle.

Numerical Studies on Trapped-Vortex Concepts for Stable Combustion

1998 ◽  
Vol 120 (1) ◽  
pp. 60-68 ◽  
Author(s):  
V. R. Katta ◽  
W. M. Roquemore
Keyword(s):  
Drag Coefficient ◽  
Reacting Flow ◽  
Flow Conditions ◽  
Third Order ◽  
Cold Flow ◽  
Flow Simulations ◽  
Numerical Studies ◽  
Dynamic Flows ◽  
Experimental Findings ◽  
Trapped Vortex

Spatially locked vortices in the cavities of a combustor aid in stabilizing the flames. On the other hand, these stationary vortices also restrict the entrainment of the main air into the cavity. For obtaining good performance characteristics in a trapped-vortex combustor, a sufficient amount of fuel and air must be injected directly into the cavity. This paper describes a numerical investigation performed to understand better the entrainment and residence-time characteristics of cavity flows for different cavity and spindle sizes. A third-order-accurate time-dependent Computational Fluid Dynamics with Chemistry (CFDC) code was used for simulating the dynamic flows associated with forebody-spindle-disk geometry. It was found from the nonreacting flow simulations that the drag coefficient decreases with cavity length and that an optimum size exists for achieving a minimum value. These observations support the earlier experimental findings of Little and Whipkey (1979). At the optimum disk location, the vortices inside the cavity and behind the disk are spatially locked. It was also found that for cavity sizes slightly larger than the optimum, even though the vortices are spatially locked, the drag coefficient increases significantly. Entrainment of the main flow was observed to be greater into the smaller-than-optimum cavities. The reacting-flow calculations indicate that the dynamic vortices developed inside the cavity with the injection of fuel and air do not shed, even though the cavity size was determined based on cold-flow conditions.

Numerical Investigation of Gas Turbine Combustor Liner Film Cooling Slots

2018 ◽  
Author(s):  
Firat Kiyici ◽  
Ahmet Topal ◽  
Ender Hepkaya ◽  
Sinan Inanli
Keyword(s):  
Heat Transfer ◽  
Prandtl Number ◽  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Turbulent Prandtl Number ◽  
Surface Cooling ◽  
Gas Turbine Combustor ◽  
Cooling Effectiveness ◽  
Combustor Liner

A numerical study, based on experimental work of Inanli et al. [1] is conducted to understand the heat transfer characteristics of film cooled test plates that represent the gas turbine combustor liner cooling system. Film cooling tests are conducted by six different slot geometries and they are scaled-up model of real combustor liner. Three different blowing ratios are applied to six different geometries and surface cooling effectiveness is determined for each test condition by measuring the surface temperature distribution. Effects of geometrical and flow parameters on cooling effectiveness are investigated. In this study, Conjugate Heat Transfer (CHT) simulations are performed with different turbulence models. Effect of the turbulent Prandtl Number is also investigated in terms of heat transfer distribution along the measurement surface. For this purpose, turbulent Prandtl number is calculated with a correlation as a function of local surface temperature gradient and its effect also compared with the constant turbulent Prandtl numbers. Good agreement is obtained with two-layered k–ϵ with modified Turbulent Prandtl number.

scholarly journals Radiative Heat Transfer From Gas Turbine Flames

1979 ◽  
Author(s):  
C. A. Ferguson ◽  
A. M. Mellor
Keyword(s):  
Heat Transfer ◽  
Heat Flux ◽  
Gas Turbine ◽  
Radiative Heat ◽  
Normal Component ◽  
Particle Analysis ◽  
Soot Concentration ◽  
Gas Turbine Combustor ◽  
Turbulent Fluctuations ◽  
Model Gas Turbine Combustor

Measurements have been made of the normal component of the radiative heat flux to the wall of a model gas turbine combustor with and without a mirrored background. Measurements have also been made of the centerline soot concentration. The data show that the heat flux correlated with the soot concentration but not universally, since JET A fuel yielded a different curve 1han DIESEL fuel. A theoretical analysis of the heat flux from a soot suspension was formulated. A criterion was established for the use of a small particle analysis. Finally, it is shown that there is no correspondence between theory and these experiments. It is speculated that turbulent fluctuations need to be modeled.

A Computational Model for the Study of Gas Turbine Combustor Dynamics

1999 ◽  
Vol 121 (2) ◽  
pp. 243-248 ◽  
Author(s):  
D. M. Costura ◽  
P. B. Lawless ◽  
S. H. Fankel
Keyword(s):  
Gas Turbine ◽  
Mass Conservation ◽  
Single Step ◽  
Combustion Model ◽  
Reacting Flow ◽  
Gas Turbine Combustor ◽  
Splitting Algorithm ◽  
Simulation Code ◽  
One Dimensional ◽  
Engine Simulation

A dynamic combustor model is developed for inclusion into a one-dimensional full gas turbine engine simulation code. A flux-difference splitting algorithm is used to numerically integrate the quasi-one-dimensional Euler equations, supplemented with species mass conservation equations. The combustion model involves a single-step, global finite-rate chemistry scheme with a temperature-dependent activation energy. Source terms are used to account for mass bleed and mass injection, with additional capabilities to handle momentum and energy sources and sinks. Numerical results for cold and reacting flow for a can-type gas turbine combustor are presented. Comparisons with experimental data from this combustor are also made.

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