Computer-Aided Dimensioning and Validation of a Versatile Test Facility for Combustion Chambers and Turbines

2009 ◽  
Author(s):  
Thomas Leitgeb ◽  
Fabrice Giuliani ◽  
Andreas Niederhammer ◽  
Hermann-Peter Pirker
Keyword(s):  
Mass Flow ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Test Facility ◽  
Compressor Station ◽  
Pressure Drops ◽  
Air Supply ◽  
University Of Technology ◽  
Air System ◽  
Core Concepts

The continuous flow test facility at Graz University of Technology was originally designed for cold sub- and transonic experimental research on different turbine stages (2001-GT-0489). The operation range of the facility was recently extended to hot flows for investigations on the behavior of high-temperature resistant sensors embedded in gas-turbines and analysis of cooling systems of turbine blades or multiple-burner combustors, where each air supply is driven separately. Therefore, a 5 MW thermal air heater has been connected to the institute’s 3 MW compressor station. The dimensioning of the air system was done with IPSE-pro which is a commercial software package for simulation of basic thermodynamic processes. The standard modules of IPSE-pro were modified for calculating the mass flow distributions with respect to the prevailing pressure drops. As the air system is complex and relies on control valves to maintain specific mass flow rates, IPSEpro allows analysis of the behaviour of the test facility at several compressor station configurations. The main test facility dimensions and characteristics, as well as the most important equations describing the component models of IPSEpro are shown. Simulation results of several operation points are compared to measured data to validate the methodology. This work was done in the frame of the European research program New Aero Engine Core Concepts (NEWAC) at Graz University of Technology.

First Results of a New Test Rig for the Research on the Internal Air System of an Industrial Gas Turbine

2012 ◽  
Author(s):  
André Günther ◽  
Wieland Uffrecht ◽  
Stefan Odenbach ◽  
Volker Caspary
Keyword(s):  
Reynolds Number ◽  
Mass Flow ◽  
Gas Turbines ◽  
Flow Parameter ◽  
Outer Radius ◽  
Gap Size ◽  
Test Rig ◽  
Air Supply ◽  
Air System ◽  
Cooling Air

Improvement of the internal air system has great impact on the efficiency and power of gas turbines. This paper describes a new two-stage test rig for research on the cooling air supply of industrial gas turbines. The design is modeled on a simplified geometry of the internal cavities of the high pressure turbine with receiver holes simulating the restriction imposed by internal blade cooling flow circuits. The test rig consists of a rotor-stator cavity and a full rotating cavity. The Stage One supply and the Stage Two supply are separated inside the rotorstator cavity. The intended aim of the research is the branched cooling air supply. The rim seal flow, which effect on cavity flows is known to be non-trivial, is outside the scope of this area of interest. This paper concentrates on the flow path supplying the Stage Two. Variations of the axial gap size and the radial location of the connecting holes respectively the outlets of the rotor-stator cavity are described here. The air enters axially without pre-swirl at the outer radius of the stator and leaves the rotor-stator cavity through three rotating, axially directed connecting holes at a radius depending on the investigated case, which causes axial throughflow in Case 1 and radial inflow in Case 2. The experimental results show that the net cavity mass flow, presented in terms of a reduced mass flow parameter, increases with increasing pressure ratio, rotational Reynolds number and gap size. The increase due to a larger gap size depends on the rotation and is less prominent at higher rotational Reynolds numbers. An axial throughflow at the outer radius results in higher values of the reduced mass flow parameter, as compared to the case with radial inflow. The difference between the two cases increases with increasing rotational Reynolds number. Measured static pressure fluctuations inside the rotor-stator cavity due to the rotating nozzles can be raised up to ± 4% of the mean in the case with the small gap and the outlet at outer radius. The Pitot probe measurements show a low swirl ratio, radial outflow near the rotor and radial inflow close to the stator, which is consistent with Batchelor-type flow.

scholarly journals Aero-Thermal Design and Testing of Advanced Turbine Blades

1997 ◽  
Author(s):  
M. Haendler ◽  
D. Raake ◽  
M. Scheurlen
Keyword(s):  
Gas Turbines ◽  
Full Range ◽  
Turbine Blades ◽  
Design Procedure ◽  
Thermal Design ◽  
Test Facility ◽  
Optical Pyrometer ◽  
Electrical Systems ◽  
Operation Conditions ◽  
Improved Performance

Based on the experience gained with more than 80 machines operating worldwide in 50 and 60 Hz electrical systems respectively, Siemens has developed a new generation of advanced gas turbines which yield substantially improved performance at a higher output level. This “3A-Series” comprises three gas turbine models ranging from 70 MW to 240 MW for 50 Hz and 60 Hz power generation applications. The first of the new advanced gas turbines with 170 MW and 3600 rpm was tested in the Berlin factory test facility under the full range of operation conditions. It was equipped with various measurement systems to monitor pressures, gas and metal temperatures, clearances, strains, vibrations and exhaust emissions. This paper presents the aero-thermal design procedure of the highly thermal loaded film cooled first stage blading. The predictions are compared with the extensive optical pyrometer measurements taken at the Siemens test facility on the V84.3A machine under full load conditions. The pyrometer was inserted at several locations in the turbine and radially moved giving a complete surface temperature information of the first stage vanes and blades.

Design and Testing of a Can Combustor for a Small Gas Turbine Application

2013 ◽  
Author(s):  
K. V. L. Narayana Rao ◽  
N. Ravi Kumar ◽  
G. Ramesha ◽  
M. Devathathan
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Gas Turbines ◽  
Pressure Loss ◽  
High Energy ◽  
Experimental Results ◽  
High Mass ◽  
Test Facility ◽  
Design Requirements

Can type combustors are robust, with ease of design, manufacturing and testing. They are extensively used in industrial gas turbines and aero engines. This paper is mainly based on the work carried out in designing and testing a can type combustion chamber which is operated using JET-A1 fuel. Based on the design requirements, the combustor is designed, fabricated and tested. The experimental results are analysed and compared with the design requirements. The basic dimensions of the combustor, like casing diameter, liner diameter, liner length and liner hole distribution are estimated through a proprietary developed code. An axial flow air swirler with 8 vanes and vane angle of 45 degree is designed to create a re-circulation zone for stabilizing the flame. The Monarch 4.0 GPH fuel nozzle with a cone angle of 80 degree is used. The igniter used is a high energy igniter with ignition energy of 2J and 60 sparks per minute. The combustor is modelled, meshed and analysed using the commercially available ansys-cfx code. The geometry of the combustor is modified iteratively based on the CFD results to meet the design requirements such as pressure loss and pattern factor. The combustor is fabricated using Ni-75 sheet of 1 mm thickness. A small combustor test facility is established. The combustor rig is tested for 50 Hours. The experimental results showed a blow-out phenomenon while the mass flow rate through the combustor is increased beyond a limit. Further through CFD analysis one of the cause for early blow out is identified to be a high mass flow rate through the swirler. The swirler area is partially blocked and many configurations are analysed. The optimum configuration is selected based on the flame position in the primary zone. The change in swirler area is implemented in the test model and further testing is carried out. The experimental results showed that the blow-out limit of the combustor is increased to a good extent. Hence the effect of swirler flow rate on recirculation zone length and flame blow out is also studied and presented. The experimental results showed that the pressure loss and pattern factor are in agreement with the design requirements.

scholarly journals Impact of a Cooled Cooling Air System on the External Aerodynamics of a Gas Turbine Combustion System

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
A. Duncan Walker ◽  
Bharat Koli ◽  
Liang Guo ◽  
Peter Beecroft ◽  
Marco Zedda
Keyword(s):  
Gas Turbines ◽  
Pressure Loss ◽  
Total Pressure ◽  
Outer Wall ◽  
Total Pressure Loss ◽  
Test Facility ◽  
Combustion System ◽  
Air System ◽  
External Aerodynamics ◽  
Cooling Air

To manage the increasing turbine temperatures of future gas turbines a cooled cooling air system has been proposed. In such a system some of the compressor efflux is diverted for additional cooling in a heat exchanger (HX) located in the bypass duct. The cooled air must then be returned, across the main gas path, to the engine core for use in component cooling. One option is do this within the combustor module and two methods are examined in the current paper; via simple transfer pipes within the dump region or via radial struts in the prediffuser. This paper presents an experimental investigation to examine the aerodynamic impact these have on the combustion system external aerodynamics. This included the use of a fully annular, isothermal test facility incorporating a bespoke 1.5 stage axial compressor, engine representative outlet guide vanes (OGVs), prediffuser, and combustor geometry. Area traverses of a miniature five-hole probe were conducted at various locations within the combustion system providing information on both flow uniformity and total pressure loss. The results show that, compared to a datum configuration, the addition of transfer pipes had minimal aerodynamic impact in terms of flow structure, distribution, and total pressure loss. However, the inclusion of prediffuser struts had a notable impact increasing the prediffuser loss by a third and consequently the overall system loss by an unacceptable 40%. Inclusion of a hybrid prediffuser with the cooled cooling air (CCA) bleed located on the prediffuser outer wall enabled an increase of the prediffuser area ratio with the result that the system loss could be returned to that of the datum level.

Experimental and Numerical Analysis of the Flow Structure and Dust Separation Inside a Pre-Swirl Cooling Air System

2003 ◽  
Author(s):  
O. Schneider ◽  
H. J. Dohmen ◽  
F.-K. Benra ◽  
D. Brillert
Keyword(s):  
Numerical Analysis ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Flow Conditions ◽  
Test Rig ◽  
Complex Flow ◽  
Air System ◽  
Cooling Air

Improvements in efficiency and performance of gas turbines require a better understanding of the internal cooling air system which provides the turbine blades with cooling air. With the increase of cooling air passing through the internal air system, a greater amount of air borne particles is transported to the film cooling holes at the turbine blade surface. In spite of their small size, these holes are critical for blockage. Blockage of only a few holes could have harmful effects on the cooling film surrounding the blade. As a result, a reduced mean time between maintenance or even unexpected operation faults of the gas turbine during operation could occur. Experience showed a complex interaction of cooling air under different flow conditions and its particle load. To get more familiar with all these influences and the system itself, a test rig has been built. With this test rig, the behavior of particles in the internal cooling air system can be studied at realistic flow conditions compared to a modern, heavy duty gas turbine. It is possible to simulate different particle sizes and dust concentrations in the coolant air. The test rig has been designed to give information about the quantity of separated particles at various critical areas of the internal air system [1]. The operation of the test rig as well as analysis of particles in such a complex flow system bear many problems, addressed in previous papers [1,2,3]. New theoretical studies give new and more accurate results, compared to the measurements. Furthermore the inspection of the test rig showed dust deposits at unexpected positions of the flow path, which will be discussed by numerical analysis.

Frost Growth in Regenerative Wheels

2005 ◽  
Vol 127 (9) ◽  
pp. 1015-1026 ◽  
Author(s):  
Wei Shang ◽  
Hong Chen ◽  
Robert W. Besant
Keyword(s):  
Pressure Drop ◽  
Relative Humidity ◽  
Mass Flow ◽  
Early Stage ◽  
Growth Period ◽  
Test Facility ◽  
Regenerative Heat ◽  
Pressure Drops ◽  
Exhaust Temperature ◽  
Frost Growth

An experimental investigation was carried out for frost growth in a desiccant-coated regenerative wheel. The test facility was set up following ASHRAE Standard 84-1991R. Temperature, relative humidity, mass flow rate, and pressure drops were measured at each measuring station. Photos of frost within energy wheel flow channels show frost accumulation. The problem of frost growth within the narrow parallel flow passages of a regenerative heat or energy rotary wheel is formulated for a very cold-temperature ventilation application. Frost growth is assumed to grow as a porous media while the wheel is exposed to warm humid airflow on the exhaust side. While the wheel is exposed to cold dry airflow on the supply side, the frost is cooled but no frost grows. This cyclic frost growth and cooling process is continued with each wheel rotation. An analytical/numerical model is developed to simulate these frost properties over the depth of the wheel and as a function of time. Simulation results are used to interpret experimental data for the early stage of frost growth on a typical energy wheel with a cold supply air temperature of −40°C, a warm exhaust temperature of 20 °C and 40% relative humidity. Pressure drop measurements across a wheel taken for constant mass flow conditions revealed some very significant fluctuations of up to 100% of original pressure drop with a period ranging from 2 to 4 min for a wheel speed of 20 rpm. Each fluctuation in pressure drop is interpreted to imply a catastrophic failure of the outer frost layer sequenced over 1–2 min throughout the wheel followed by another frost growth period on top of a slightly thicker frost base.

Separation of Particles in the Secondary Air System of Gas Turbines

2011 ◽  
Author(s):  
Natalia Garci´a Vi´llora ◽  
Klaus Dullenkopf ◽  
Hans-Jo¨rg Bauer
Keyword(s):  
Film Cooling ◽  
Gas Turbines ◽  
Separation Efficiency ◽  
Cooling System ◽  
Turbine Blades ◽  
Spherical Particles ◽  
Experimental Investigations ◽  
Air System ◽  
Secondary Air ◽  
Aero Engines

Particles contaminating the secondary air system of land based gas turbines or aero-engines can cause serious problems in various engine components, particularly in the cooling system. The capability of the pre-swirl system in separating particles will be described in this paper. So far, only a few publications can be found on experimental investigations on this subject. The work presented in this paper attempts to give a contribution to fill this gap and thus represents a further step towards a better understanding of the behaviour of solid contaminants in the secondary air system. Due to the strong swirl in the pre-swirl cavity, the aero-dynamical forces can be used to separate particles, thus preventing depositions inside the turbine blades or even block-age of the film cooling holes. Numerous experiments in a pre-swirl system have been performed using spherical particles and non-spherical particles. As reference cases, three types of spheres, with two size ranges and different materials, were used to understand how size and density influence the separation efficiency. For further experiments, irregularly-shaped particles, more similar to the ones found in real aero-engines, were used too. The separation efficiency was investigated at different pre-swirl nozzle pressure ratios, rotational speeds and radial mass flows. The results are presented in relation to the particle Reynolds numbers, drag coefficients, Stokes numbers and swirl ratios in the pre-swirl cavity.

Ultra-Low NOx Advanced Vortex Combustor

2006 ◽  
Author(s):  
Ryan G. Edmonds ◽  
Robert C. Steele ◽  
Joseph T. Williams ◽  
Douglas L. Straub ◽  
Kent H. Casleton ◽  
...  
Keyword(s):  
Pressure Drop ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Operating Conditions ◽  
Test Facility ◽  
Attractive Alternative ◽  
Lean Premixed Combustion ◽  
Pressure Drops ◽  
Wide Range ◽  
Lean Premixed

An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.

Investigation of Internal Cooling Air Flow of Gas Turbines With Attention to Heat Transfer

2003 ◽  
Author(s):  
D. Brillert ◽  
F.-K. Benra ◽  
H. J. Dohmen ◽  
O. Schneider
Keyword(s):  
Heat Transfer ◽  
Gas Turbines ◽  
Turbine Blades ◽  
Internal Cooling ◽  
Flow Physics ◽  
Cooling Flow ◽  
Air System ◽  
Secondary Air ◽  
Cooling Air ◽  
Material Temperature

The cooling air in the secondary air system of gas turbines is routed through the inside of the rotor shaft. The air enters the rotor through an internal extraction in the compressor section and flows through different components to the turbine blades. Constant improvements of the secondary air system is a basic element to increase efficiency and power of heavy duty gas turbines. It is becoming more and more important to have a precise calculation of the heat transfer and air temperature in the internal cooling air system. This influences the cooling behavior, the material temperature and consequently the cooling efficiency. The material temperature influences the stresses and the creep behavior which is important for the life time prediction and the reliability of the components of the engine. Furthermore, the material temperature influences the clearances and again the cooling flow, e.g. the amount of mass flow rate, hot gas ingestion etc. This paper deals with an investigation of the influence of heat transfer on the internal cooling air system and on the material temperature. It shows a comparison between numerical calculations with and without heat transfer. Firstly, the Navier-Stokes CFD calculation shows the cooling flow physics of different parts of the secondary air system passages with solid heat transfer. In the second approach, the study is expanded to consider the cooling flow physics under conditions without heat transfer. On the basis of these investigations, the paper shows a comparison between the flow with and without heat transfer. The results of the simulation with heat transfer show a negligible influence on the cooling flow temperature and a stronger influence on the material temperature. The results of the calculations are compared with measured data. The influence on the material temperature is verified with measured material temperatures from a Siemens Model V84.3A gas turbine prototype.

Admissible Roughness in Gas Turbines

2015 ◽  
Author(s):  
Martin N. Goodhand
Keyword(s):  
Gas Turbines ◽  
Turbine Blades ◽  
Engine Performance ◽  
Stagnation Pressure ◽  
Roughness Height ◽  
Analytical Models ◽  
Stagnation Temperature ◽  
General Picture ◽  
Pressure Drops ◽  
Gas Turbine Blades

Roughness below a certain, admissible level will not increase an aerofoil’s skin friction and thus will not impact on engine performance. In this paper a simple model is developed that demonstrates how this admissible roughness height changes through the engine. The model is determined by combining existing analytical models and is backed up by computational validation where necessary. It is shown that, given a fixed inlet/exit stagnation temperature and pressure to a blade row, the admissible roughness height is only a weak function of chord Reynolds number and Mach number for typical gas turbine blades. The aerofoil geometry/duty is also shown to have little impact. This allows the model to give a general picture of where roughness matters, irrespective of the exact details of the flow conditions/blade geometries. The model shows that the admissible roughness height decreases as the stagnation pressure increases. The lowest admissible roughness level occurs at the high pressure end of the compressor at sea-level; the admissible roughness increases as the stagnation pressure drops towards the front of the compressor. Turbines are also most sensitive to roughness close to the combustor, but even there the admissible roughness will be around three times greater than at the rear of the compressor.

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