Multi-Fidelity Combustor Design and Experimental Test for a Micro Gas Turbine System (original) (raw)
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An integrated approach for optimal design of micro gas turbine combustors
Journal of Thermal Science, 2009
The present work presents an approach for the optimized design of small gas turbine combustors, that integrates a 0-D code, CFD analyses and an advanced game theory multi-objective optimization algorithm. The output of the 0-D code is a baseline design of the combustor, given the required fuel characteristics, the basic geometry (tubular or annular) and the combustion concept (i.e. lean premixed primary zone or diffusive processes). For the optimization of the baseline design a simplified parametric CAD/mesher model is then defined and submitted to a CFD code. Free parameters of the optimization process are position and size of the liner holes arrays, their total area and the shape of the exit duct, while different objectives are the minimization of NO x emissions, pressure losses and combustor exit Pattern Factor. A 3D simulation of the optimized geometry completes the design procedure. As a first demonstrative example, the integrated design process was applied to a tubular combustion chamber with a lean premixed primary zone for a recuperative methane-fuelled small gas turbine of the 100 kW class.
Combustion chamber design and performance for micro gas turbine application
Fuel Processing Technology, 2017
Micro-gas turbines (MGT) are small-scale independent and reliable distributed generation systems that offer potential for saving energy and reducing carbon monoxide (CO) emissions. They are expected to play a vital role in future energy supplies for remote locations with or without grid connections. In this paper, a design and development of a combustion chamber for micro-gas turbine was performed by SOLID-WORKS and computational fluid dynamics (CFD) ANSYS-FLUENT simulation software. Different chamber geometries were used to simulate with species transport and non-premixed combustion models to determine the optimum chamber design. The best chamber geometry adopted after optimization was 50 mm flame holder diameter, 60 cm chamber height, having 4 holes of 6, 8 and10 mm with dead zone between the combustion zone and dilution zone. A two-stage MGT was developed based on vehicular turbochargers to test the chamber. The experimental test of the chamber with liquefied petroleum gas (LPG) fuel resulted in a stable combustion with CO emission below 100 ppm and turbine inlet temperature below 900°C.
Design of Combustor for Micro Gas Turbine Test Rig and Its Performance Prediction
Jurnal Teknologi
Stringent emission rules, air pollution, fluctuation of fuel price and depletion of fossil fuel resources are driving the industry to seek for better alternative of power generation. Micro gas turbine (MGT) provides a promising potential to solve the facing problems. MGT could be used in many applications such as in range extender vehicle, auxiliary power generator, power backup system, combine heat and power system, etc. Combustor plays a very crucial role in MGT system as its performance directly affects the emission quality, power output and fuel consumption of the entire system. This paper demonstrates the literature review, design methodology and performance prediction of the combustor designed for a 14.5kW MGT test rig.
Numerical Simulations of a Micro Combustion Chamber
47th AIAA Aerospace Sciences Meeting including The New Horizons Forum and Aerospace Exposition, 2009
The goal of this paper is to investigate the performance of microcombustors for microturbines and for propulsion. Such field is currently under rapid development because of new market requirements. In particular, main areas of interest for microcombustion are propulsion, e.g., for UAVs, and micro-electrical power generators. This study is focused on a cylindrical microcombustor fed by methane and air, with diameter and height 0.006m and 0.009m, respectively. Following a preliminary scaling analysis, two combustion models were tested, and 3D RANS numerical simulations were performed. The two combustion models simulating micro-combustor flames are the eddy dissipation model with fast chemistry and the flamelet model. Both use a novel 2-step reduced kinetics mechanism: this was properly tuned for the present device. Results indicate that the two models predict similar results for what concerns the chamber maximum temperature and outlet temperature; they differ in predicting combustion efficiency: in particular the eddy dissipation model underpredicts the measured combustion efficiency while the flamelet model overpredicts it. Compared to the eddy dissipation model, the advantage of the flamelet model is its enormous computational time saving. This work should be seen as an advance in the understanding of how to design, and what to expect from future microcombustors applications.
Chemical engineering transactions, 2015
In the field of micro gas turbine, attention must be paid on the design of the combustion chamber to reduce NOx formation without compromising combustion efficiency. To this goal flameless combustion represents an appealing solution. The present work aims at the design and optimization of a combustion chamber for a micro gas-turbine, operating in flameless combustion regime. The feasibility of such system is analysed with numerical simulations, using CFD-tools. Among the several configurations under investigations, it is possible to identify one that guarantees the maximum combustion efficiency, the minimum pressure losses as well as the minimum overall dimension.
LES Simulation of an Ultra-Micro Combustion Chamber Based on a 177 Reactions Mechanism
ASME 2010 10th Biennial Conference on Engineering Systems Design and Analysis, Volume 1, 2010
Goal of this paper is to investigate the performance of microcombustors, a field currently under rapid development in particular for propulsion, e.g., UAVs and micro-electrical power generators. This study focuses on a cylindrical microcombustor fed by methane and air, with diameter and height 0.025m and 0.06m respectively. A 3D LES simulation with the WALE subgrid scale models, the EDC combustion-chemistry model and the reduced GRIMech1.2 mechanism has been performed. The calculated maximum temperature inside the chamber, the gas exhaust temperature and the combustion efficiency are compared and discussed. Reported results are at 0.05s, that is after 5 residence times. This ultra-microcombustor displays an excellent combustion efficiency which makes it a suitable for application in ultrasmall energy producing devices. This work is part of a broader work that includes an experimental analysis, and it was conceived as a contribution towards a better understanding of the most convenient simulations guidelines for future microcombustor applications, and to a more accurate estimate of the performance parameters to apply to first-order design procedures.
Design, Evaluation and Performance Analysis of Staged Low Emission Combustors
Journal of Engineering for Gas Turbines and Power, 2014
The most uncertain and challenging part in the design of a gas turbine has long been the combustion chamber. There has been a large number of experimentations in industry and universities alike to better understand the dynamic and complex processes that occur inside a combustion chamber. This study concentrates on gas turbine combustors, as a whole, and formulates a theoretical design procedure for staged combustors, in particular. Not much of the literature currently available in the public domain provides intensive study on designing staged combustors. The work covers an extensive study of the design methods applied in conventional combustor designs, which includes the reverse flow combustor and the axial flow annular combustors. The knowledge acquired from this study is then applied to develop a theoretical design methodology for double staged (radial and axial) low emission annular combustors. Additionally, a model combustor is designed for each type, radial and axial, of stagin...
PREDICTION OF THE FLOW INSIDE A MICRO GAS TURBINE COMBUSTOR
2008
The main purpose of this study is to predict the flow dynamics inside a micro gas turbine combustor model. The flow field inside the combustor is controlled by the liner shape and size, wall side holes shape, size and arrangement (primary, secondary and dilution holes), and primary air swirler configuration. Air swirler adds sufficient swirling to the inlet flow to generate central recirculation region (CRZ) which is necessary for flame stability and fuel air mixing enhancement. Therefore designing an appropriate air swirler is a challenge to produce stable, efficient and low emission combustion with low pressure losses. Four axial flat vane swirlers with 20°, 30°, 45° and 60° vane angle corresponding to swirl number of 0.27, 0.42, 0.74, and 1.285 respectively were used in this analysis to show vane angle effect on the internal flow field. The flow behavior was investigated numerically using CFD solver FLUENT 6.2. This study has provided physical insight into the flow pattern inside the combustion chamber. Results show that the swirling action is augmented with the increase in the vane angle, which leads to increase in the turbulence strength, recirculation zone size, and amount of recirculated mass. However, all these happen at the expense of the increase in pressure losses. In case of 20° swirler (swirl number < 0.4), the produced swirling flow is not enough to generate CRZ.
Investigation of combustion in miniaturised combustor for application to micro gas turbines
Progress in Propulsion Physics, 2009
Assessing the feasibility of combustion in miniaturised combustors (volume less than 1 cm 3) is a key point for the development of micro gas turbines. This paper presents the results obtained in a combustion chamber operating with a hydrogenair mixture. A stable combustion was obtained with an output power between 100 and 1200 W, for air mass §ow rate from 0.1 to 0.5 g/s, and equivalence ratio between 0.3 and 0.7. Experimental results were obtained using thermocouples to measure temperature of the burnt gases at the outlet of the combustor, and information on combustion e©ciency and output power was derived. In addition, laser-based measurements were performed using spontaneous Raman spectroscopy and Rayleigh scattering to determine radial pro¦les of temperature and main species concentrations at the outlet of the combustor.