A New Test Facility for Investigating the Interaction Between Swirl Flow and Wall Cooling Films in Combustors

Author(s):  
B. Wurm ◽  
A. Schulz ◽  
H.-J. Bauer

Swirl stabilization of flames is typically used in combustors of aero engines and gas turbines for power generation. In the near wall region of the combustor liner, the swirling flow interacts in a very particular way with wall cooling films. This interaction and its effect on the local wall cooling performance gave reason to design and commission a new atmospheric test rig for detailed aerodynamic and thermal studies. The new test rig includes three burners in a planar arrangement. Special emphasis was placed on the simulation of realistic operating conditions as Reynolds number and temperature ratio. The liner cooling and the formation of a starter cooling film can be independently controlled. The rectangular flow channel is equipped with large windows to allow for laser optical diagnostics like PIV and 3-component LDA. The thermal analyses are based on highly resolved temperature mappings of the cooled surface utilizing infrared thermography. First experimental results are presented in terms of static pressure distributions on the combustor liner and PIV contour plots of the swirl flow. The static pressure pattern corresponds well to the up wash and downwash regions of the swirl flow.

Author(s):  
C. Mende ◽  
O. Liedtke ◽  
A. Schulz ◽  
H.-J. Bauer

This paper describes the design and operation of a new test rig, which allows the simulation of real engine operating conditions leading to Low-Cycle Fatigue of combustor liner tiles. The experimental setup will provide high-quality data for the development of damage models. At first the design data of the test rig will be derived from the relevant damage mechanisms in Combustor Liner Tiles (CLT). Then the construction of the test rig and its integration into an existing high temperature high pressure test facility will be elucidated. Finally experimental data of a typical simulated thermal cycle is shown.


Author(s):  
Jingjing Luo ◽  
Dieter Brillert

Abstract Dry gas lubricated non-contacting mechanical seals (DGS), most commonly found in centrifugal compressors, prevent the process gas flow into the atmosphere. Especially when high speed is combined with high pressure, DGS is the preferred choice over other sealing alternatives. In order to investigate the flow field in the sealing gap and to facilitate the numerical prediction of the seal performance, a dedicated test facility is developed to carry out the measurement of key parameters in the gas film. Gas in the sealing film varies according to the seal inlet pressure, and the thickness of gas film depends on this fluctuated pressure. In this paper, the test facility, measurement methods and the first results of static pressure measurements in the sealing gap of the DGS obtained in the described test facility are presented. An industry DGS with three-dimensional grooves on the surface of the rotating ring, where experimental investigations take place, is used. The static pressure in the gas film is measured, up to 20 bar and 8,100 rpm, by several high frequency ultraminiature pressure transducers embedded into the stationary ring. The experimental results are discussed and compared with the numerical model programmed in MATLAB, the characteristic and magnitude of which have a good agreement with the numerical simulations. It suggests the feasibility of measuring pressure profiles of the standard industry DGS under pressurized dynamic operating conditions without altering the key components of the seal and thereby affecting the seal performance.


Author(s):  
Christian Kunkel ◽  
Jan Werner ◽  
Daniel Franke ◽  
Heinz-Peter Schiffer ◽  
Fabian Wartzek ◽  
...  

Abstract With the well-known Transonic Compressor Darmstadt (TCD) in operation since 1994, profound knowledge in designing and operating a sophisticated test-rig is available at the Institute of Gas Turbines and Aerospace Propulsion of TU Darmstadt. During this period, TCD has been subject to a vast number of redesigns within different measurement campaigns (see [1], [2], [3], [4], [5], [6], [7], [8]). To expand the capabilities and ensure a sustainable process of compressor research, a new test facility was designed and built by the institute. The new test rig Transonic Compressor Darmstadt 2 (TCD2) features increased power for higher pressure ratios and higher mass-flow, a state of the art control system, increased flexibility towards different compressor geometries and modern data acquisition hardware and software. Following the successful commissioning of the test-rig in March 2018, a first measurement campaign has been conducted. Early test results regarding aerodynamic performance and aeroelastic effects of the test compressor are presented together with a detailed overview of test-rig infrastructure and control systems as well as the test compressor and the measurement hardware.


Author(s):  
Robin R. Jones ◽  
Oliver J. Pountney ◽  
Bjorn L. Cleton ◽  
Liam E. Wood ◽  
B. Deneys J. Schreiner ◽  
...  

Abstract In modern gas turbines, endwall contouring (EWC) is employed to modify the static pressure field downstream of the vanes and minimise the growth of secondary flow structures developed in the blade passage. Purge flow (or egress) from the upstream rim-seal interferes with the mainstream flow, adding to the loss generated in the rotor. Despite this, EWC is typically designed without consideration of mainstream-egress interactions. The performance gains offered by EWC can be reduced, or in the limit eliminated, when purge air is considered. In addition, EWC can result in a reduction in sealing effectiveness across the rim seal. Consequently, industry is pursuing a combined design approach that encompasses the rim-seal, seal-clearance profile and EWC on the rotor endwall. This paper presents the design of, and preliminary results from a new single-stage axial turbine facility developed to investigate the fundamental fluid dynamics of egress-mainstream flow interactions. To the authors’ knowledge this is the only test facility in the world capable of investigating the interaction effects between cavity flows, rim seals and EWC. The design of optical measurement capabilities for future studies, employing volumetric velocimetry and planar laser induced fluorescence are also presented. The fluid-dynamically scaled rig operates at benign pressures and temperatures suited to these techniques and is modular. The facility enables expedient interchange of EWC (integrated into the rotor bling), blade-fillet and rim-seals geometries. The measurements presented in this paper include: gas concentration effectiveness and swirl measurements on the stator wall and in the wheel-space core; pressure distributions around the nozzle guide vanes at three different spanwise locations; pitchwise static pressure distributions downstream of the nozzle guide vane at four axial locations on the stator platform.


Author(s):  
M. B. Schmitz ◽  
G. Fitzky

The turbocharger test facility can be operated in two different modes. In the first mode, the turbocharger turbine is driven by an external blower and a combustor. The compressor blows off through the chimney. In the second mode the turbocharger is operated similar to a gas turbine: the turbine drives the turbocharger compressor which pressurizes the combustion chamber. This study is focused on the surge cycle of the turbocharger for both operation modes of the test facility. The turbocharger has to withstand surge for all pressure ratios it is designed for without damaging the test rig. Especially for small compressors large plenum volumes can cause such damages. The dynamical model of the system is developed based on the work done by Greitzer [5], [6] and has been extended to the special requirements of the turbocharger test rig. For the components of the turbocharger a quasi-steady behavior with respect to the time scales of the surge cycle is assumed. Consequently, the experimentally obtained steady state characteristics for both compressor and turbine are applied to the model. In order to describe the compressor behavior for backflow conditions, the compressor map is extended for negative mass flow. The theoretical model is calibrated on experimental data. Thereafter the model is used to predict the surge cycle for different operation conditions. For the two operation modes, the blow-off and the recirculation operation, the time resolved values of static pressure and speed oscillation were recorded and compared to the theoretical predictions.


Author(s):  
Hari Prasad Neopane ◽  
Bhola Thapa ◽  
Ole Gunnar Dahlhaug

This paper presents the laboratory studies of particle velocity measurement in highly swirl conditions similar to turbine flow in curved path. It includes a brief description of the developed test rig, concept of critical diameter of particle inside a Francis turbine and experimental analysis. When a particle is flowing in swirl flow, drag force and centrifugal force are two major forces influencing the particle equilibrium. The equilibrium of these two forces provides a critical diameter of the particle. While, a particle larger than the critical diameter move away from the centre and hit the wall, a particle smaller than the critical diameter flows along with the water, and ultimately sinks. For critical diameter, the particle continues to rotate in the turbine. Different shapes and sizes of particles were tested with the same operating conditions and found that triangularly shaped particles were more likely to hit the suction side of the guide vane cascade. Furthermore, this study supports the concept of separation of particles from streamlines inside the test rig, which led to the development of an operating strategy for a Francis turbine processing sediment-laden water. This study also permitted experimental verification of the size and the shape of a particle as it orbits in the turbine, until either the velocity components are changed or the particle became smaller.DOI: http://dx.doi.org/10.3126/kuset.v8i1.6034 KUSET 2012; 8(1): 1-14


1978 ◽  
Author(s):  
R. J. Russell ◽  
J. J. Witton

A study has been made of the turbine erosion problem encountered in a marinized aero gas turbine which arose from the change of fuel type necessitated by the marine application. The work has involved the development of a technique for collecting carbon shed from the combustion chamber under engine operating conditions. Tests using the collector were made with a single combustor test rig and compared to engine experience. Combustion chamber modifications were developed having low solids emissions and their emissions characterized using the collector. The data from the collector show that smaller particles than hitherto collected can produce significant long-term erosion and that reduction on both size and quantity of particles is necessary to reduce erosion to acceptable levels. The data obtained in this study are compared with other published information on the basic erosion process and erosion in gas turbines by natural mineral dusts. The implications of the results to current and future engines are discussed.


Author(s):  
John M. McFarland ◽  
Grant O. Musgrove ◽  
Sung Yong Chang ◽  
David L. Ransom

Actual gas turbine performance and component life at specific engine installations is highly dependent on the actual operating conditions, since not all engines are operated in the same manner. Due to the variability in turbine operation, it may be prudent to evaluate the operation of hot section components for turbine inlet conditions that are specific to a single installation. However, determining the actual turbine inlet conditions can be a difficult and expensive process that is usually only done on test bed gas turbines. This paper presents a method to determine turbine inlet conditions using a model calibration approach. Two-stage CFD and thermal analyses are developed to predict blade temperature. By varying the model inputs, computational predictions of blade temperature are calibrated to blade interdiffusion zone thickness measurements. In order to speed up calculations, surrogate models are used in place of the full-scale analysis codes during the calibration analysis. The result of the study is a prediction of the turbine inlet profile necessary to obtain the best agreement between predicted and measured blade temperatures.


Author(s):  
Frank Reiss ◽  
Sven-Hendrik Wiers ◽  
Ulrich Orth ◽  
Emil Aschenbruck ◽  
Martin Lauer ◽  
...  

This paper describes the development and test results of the low emission combustion system for the new industrial gas turbines in the 6–7 MW class from MAN Diesel & Turbo. The design of a robust combustion system and the achievement of very low emission targets were the most important design goals of the combustor development. During the design phase, the analysis of the combustor (i.e. burner design, air distribution, liner cooling design) was supported with different CFD tools. This advanced Dry Low Emission can combustion system (ACC) consists of 6 cans mounted externally on the gas turbine. The behavior and performance of a single can sector was tested over a wide load range and with different boundary conditions; first on an atmospheric test rig and later on a high pressure test rig with extensive instrumentation to ensure an efficient test campaign and accurate data. The atmospheric tests showed a very good performance for all combustor parts and promising results. The high pressure tests demonstrated very stable behavior at all operation modes and very low emissions to satisfy stringent environmental requirements. The whole operation concept of the combustion system was tested first on the single-can high pressure test bed and later on twin and single shaft gas turbines at MAN’s gas turbine test facility. During the engine tests, the can combustors demonstrated the expected combustion performance under real operation conditions. All emissions and performance targets were fully achieved. On the single shaft engine, the combustors were running with single digit ppm NOx levels between 50% and 100% load. The validation phase and further optimization of the gas turbines and the engine components are ongoing. The highlights of the development process and results of the combustor and engine tests will be presented and discussed within this paper.


Author(s):  
Stefan Bauer ◽  
Balbina Hampel ◽  
Thomas Sattelmayer

Abstract Vortex generators are known to be effective in augmenting the mixing of fuel jets with air. The configuration investigated in this study is a tubular air passage with fuel injection from one single orifice placed in the side wall. In the range of typical gas turbine combustor inlet temperatures, the performance vortex generator premixers (VGPs) have already been investigated for natural gas as well as for blends of natural gas and hydrogen. However, for highly reactive fuels, the application of VGPs in recuperated gas turbines is particularly challenging because the high combustor inlet temperature leads to potential risk with regard to premature self-ignition and flame flashback. As the current knowledge does not cover the temperature range far above the self-ignition temperature, an experimental investigation of the operational limits of VGPs is currently being conducted at the Thermodynamics Institute of the Technical University of Munich, Garching, Germany, which is particularly focused on reactive fuels and the thermodynamic conditions present in recuperated gas turbines with pressure ratios of 4–5. For the study presented in this paper, an atmospheric combustion VGP test rig has been designed, which facilitates investigations in a wide range of operating conditions in order to comply with the situation in recuperated microgas turbines (MGT), namely, global equivalence ratios between 0.2 and 0.7, air preheating temperatures between 288 K and 1100 K, and air bulk flow rates between 6 and 16 g/s. Both the entire mixing zone in the VGP and the primary combustion zone of the test rig are optically accessible. High-speed OH* chemiluminescence imaging is used for the detection of the flashback and blow-off limits of the investigated VGPs. Flashback and blow-off limits of hydrogen in a wide temperature range covering the autoignition regime are presented, addressing the influences of equivalence ratio, air preheating temperature, and momentum ratio between air and hydrogen on the operational limits in terms of bulk flow velocity. It is shown that flashback and blow-off limits are increasingly influenced by autoignition in the ultrahigh temperature regime.


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