scholarly journals Combustion of Fuel Surrogates: An Application to Gas Turbine Engines

2021 ◽  
Author(s):  
Mansour Al Qubeissi ◽  
Nawar Al-Esawi ◽  
Hakan Serhad Soyhan
Keyword(s):  
Gas Turbine ◽  
Combustion Process ◽  
Chemical Mechanism ◽  
Cfd Modelling ◽  
Ansys Fluent ◽  
Turbine Engine ◽  
Fuel Blends ◽  
Combustion Simulation ◽  
Fuel Surrogate ◽  
Fuel Surrogates

The previously developed models for fuel droplet heating and evaporation processes, mainly the Discrete Multi Component Model (DMCM), and Multi-Dimensional Quasi-Discrete Model (MDQDM) are investigated for the aerodynamic combustion simulation. The models have been recently improved, and generalised for a broad range of bio-fossil fuel blends so that the application areas are broadened with increased accuracy. The main distinctive features of these models are that they consider the impacts of species thermal conductivities and diffusivities within the droplets to account for the temperature gradient, transient diffusion of species and recirculation. A formulation of fuel surrogates is made, using the recently introduced model, referred to as ‘’Complex Fuel Surrogate Model (CFSM)’’ and analysing their heating, evaporation, and combustion characteristics. The CFSM is aimed to reduce the full composition of fuel to a much smaller number of components based on their mass fractions, and to formulate fuel surrogates. Such approach has provided a proof of concept with the implementation of the developed model into a commercial CFD code ANSYS-Fluent. A case study is made for the CFD modelling of gas-turbine engine using kerosene fuel surrogate. The surrogate is proposed using the CFSM. The model is implemented into ANSYS-Fluent via a user-defined function to provide the first full simulation of the combustion process. Detailed chemical mechanism is also implemented into ANSYS Chemkin for the combustion study.

scholarly journals Combustion of Fuel Surrogates: An Application to Gas Turbine Engines

Energies ◽  
2021 ◽  
Vol 14 (20) ◽  
pp. 6545
Author(s):  
Mansour Al Qubeissi ◽  
Nawar Al-Esawi ◽  
Hakan Serhad Soyhan
Keyword(s):  
Gas Turbine ◽  
Computational Time ◽  
Cfd Modelling ◽  
Ansys Fluent ◽  
Simulation Accuracy ◽  
Turbine Engine ◽  
Fuel Blends ◽  
Combustion Simulation ◽  
Fuel Surrogate ◽  
Fuel Surrogates

The previously developed approaches for fuel droplet heating and evaporation processes, mainly using the Discrete Multi Component Model (DMCM), are investigated for the aerodynamic combustion simulation. The models have been recently improved and generalised for a broad range of bio-fossil fuel blends so that the application areas are broadened with an increased accuracy. The main distinctive features of these models are that they consider the impacts of species’ thermal conductivities and diffusivities within the droplets in order to account for the temperature gradient, transient diffusion of species and recirculation. A formulation of fuel surrogates is made using the recently introduced model, referred to as “Complex Fuel Surrogate Model (CFSM)”, and analysing their heating, evaporation and combustion characteristics. The CFSM is aimed to reduce the full composition of fuel to a much smaller number of components based on their mass fractions, and to formulate fuel surrogates. Such an approach has provided a proof of concept with the implementation of the developed model into a commercial CFD code ANSYS Fluent. A case study is made for the CFD modelling of a gas turbine engine using a kerosene fuel surrogate, which is the first of its kind. The surrogate is proposed using the CFSM, with the aim to reduce the computational time and improve the simulation accuracy of the CFD model.

NMHC and VOC Speciation of the Exhaust Gas From a Gas Turbine Engine Using Alternative, Renewable and Conventional Jet A-1 Aviation Fuels

2014 ◽  
Author(s):  
Mohamed A. Altaher ◽  
Hu Li ◽  
Simon Blakey ◽  
Winson Chung
Keyword(s):  
Gas Turbine ◽  
Gas Turbine Engine ◽  
Aviation Fuel ◽  
Exhaust Gas ◽  
Turbine Engine ◽  
Fuel Blends ◽  
Auxiliary Power ◽  
Unburned Hydrocarbons ◽  
Full Power ◽  
Two Stages

This paper investigated the emissions of individual unburned hydrocarbons and carbonyl compounds from the exhaust gas of an APU (Auxiliary Power Unit) gas turbine engine burning various fuels. The engine was a single spool, two stages of turbines and one stage of centrifugal compressor gas turbine engine, and operated at idle and full power respectively. Four alternative aviation fuel blends with Jet A-1 were tested including GTL, hydrogenated renewable jet fuel and fatty acid ester. C2-C4 alkenes, benzene, toluene, xylene, trimethylbenzene, naphthalene, formaldehyde, acetaldehyde and acrolein emissions were measured. The results show at the full power condition, the concentrations for all hydrocarbons were very low (near or below the instrument detection limits). Formaldehyde was a major aldehyde species emitted with a fraction of around 60% of total measured aldehydes emissions. Formaldehydes emissions were reduced for all fuels compared to Jet A-1 especially at the idle conditions. There were no differences in acetaldehydes and acrolein emissions for all fuels; however, there was a noticeable reduction with GTL fuel. The aromatic hydrocarbon emissions including benzene and toluene are decreased for the alternative and renewable fuels.

The ultra-high efficiency gas turbine engine, UHEGT, Part II: A numerical study on reducing the stator blade surface temperature by indexing fuel injectors and using film cooling

2020 ◽  
pp. 095765092097353
Author(s):  
Seyed M Ghoreyshi ◽  
Meinhard T Schobeiri
Keyword(s):  
Surface Temperature ◽  
Gas Turbine ◽  
Film Cooling ◽  
Total Pressure ◽  
High Efficiency ◽  
Combustion Process ◽  
Blade Surface ◽  
Turbine Engine ◽  
Fuel Injectors ◽  
Stator Blade

In the Ultra-High Efficiency Gas Turbine Engine, UHEGT (introduced in our previous studies) the combustion process is no longer contained in isolation between the compressor and turbine, rather distributed within the axial gaps before each stator row. This technology substantially increases the thermal efficiency of the engine cycle to above 45%, increases power output, and reduces turbine inlet temperature. Since the combustion process is brought into the turbine stages in UHEGT, the stator blades are exposed to high-temperature gases and can be overheated. To address this issue and reduce the temperature on the stator blade surface, two different approaches are investigated in this paper. The first is indexing (clocking) of the fuel injectors (cylindrical tubes extended from hub to shroud), in which the positions of the injectors are adjusted relative to each other and the stator blades. The second is film cooling, in which cooling holes are placed on the blade surface to bring down the temperature via coolant injection. Four configurations are designed and studied via computational fluid dynamics (CFD) to evaluate the effectiveness of the two approaches. Stator blade surface temperature (as the main objective function) along with other performance parameters such as temperature non-uniformity at rotor inlet, total pressure loss over the injectors, and total power production by rotor are evaluated for all configurations. The results show that indexing presents the most promising approach in reducing the stator blade surface temperature while producing the least amount of total pressure loss.

Design, Analysis, and Manufacture of an Axial Length-Saving Disk-Oriented Engine

2020 ◽  
Vol 143 (1) ◽  
Author(s):  
Bennett M. Staton ◽  
Brian T. Bohan ◽  
Marc D. Polanka ◽  
Larry P. Goss
Keyword(s):  
Gas Turbine ◽  
Axial Length ◽  
Electric Propulsion ◽  
Guide Vane ◽  
Combustion Process ◽  
Gas Turbine Engine ◽  
Inlet Temperature ◽  
Turbine Engine ◽  
Power Extraction ◽  
Turbine Inlet

Abstract A disk-oriented engine was designed to reduce the overall length of a gas turbine engine, combining a single-stage centrifugal compressor and radial in-flow turbine (RIT) in a back-to-back configuration. The focus of this research was to understand how this unique flow path impacted the combustion process. Computational analysis was accomplished to determine the feasibility of reducing the axial length of a gas turbine engine utilizing circumferential combustion. The desire was to maintain circumferential swirl from the compressor through a U-bend combustion path. The U-bend reverses the outboard flow from the compressor into an integrated turbine guide vane in preparation for power extraction by the RIT. The computational targets for this design were a turbine inlet temperature of 1300 K, operating with a 3% total pressure drop across the combustor, and a turbine inlet pattern factor (PF) of 0.24 to produce a cycle capable of creating 668 N of thrust. By wrapping the combustion chamber about the circumference of the turbomachinery, the axial length of the entire engine was reduced. Reallocating the combustor volume from the axial to radial orientation reduced the overall length of the system up to 40%, improving the mobility and modularity of gas turbine power in specific applications. This reduction in axial length could be applied to electric power generation for both ground power and airborne distributive electric propulsion. Computational results were further compared to experimental velocity measurements on custom fuel–air swirl injectors at mass flow conditions representative of 668 N of thrust, providing qualitative and quantitative insight into the stability of the flame anchoring system. From this design, a full-scale physical model of the disk-oriented engine was designed for combustion analysis.

Validation and Comparison of Strip Seal Designs for Gas Turbine Engine Nozzle Guide Vanes

2008 ◽  
Author(s):  
Arash Farahani ◽  
Peter Childs
Keyword(s):  
Gas Turbine ◽  
Guide Vane ◽  
Gas Turbine Engine ◽  
Experimental Comparison ◽  
Cfd Modelling ◽  
Guide Vanes ◽  
Turbine Engine ◽  
Seal Design ◽  
Nozzle Guide ◽  
Nozzle Guide Vanes

Strip seals are commonly used to prevent or limit leakage flows between nozzle guide vanes (NGV) and other gas turbine engine components that are assembled from individual segments. Leakage flow across, for example, a nozzle guide vane platform, leads to increased demands on the gas turbine engine internal flow system and a rise in specific fuel consumption (SFC). Careful attention to the flow characteristics of strip seals is therefore necessary. The very tight tolerances associated with strip seals provides a particular challenge to their characterisation. This paper reports the validation of CFD modelling for the case of a strip seal under very carefully controlled conditions. In addition, experimental comparison of three types of strip seal design, straight, arcuate, and cloth, is presented. These seals are typical of those used by competing manufacturers of gas turbine engines. The results show that the straight seal provides the best flow sealing performance for the controlled configuration tested, although each design has its specific merits for a particular application.

Comparison of Numerical and Experimental Results of a Premixed DLE Gas Turbine Combustor

2001 ◽  
Author(s):  
Ruud L. G. M. Eggels ◽  
Christopher T. Brown
Keyword(s):  
Reaction Mechanism ◽  
Gas Turbine ◽  
Combustion Process ◽  
Combustion Efficiency ◽  
Gas Turbine Combustor ◽  
Cfd Modelling ◽  
Recirculation Length ◽  
Global Reaction ◽  
Presumed Pdf ◽  
Pdf Model

A numerical and experimental study on a premixed DLE gas turbine combustor has been performed. Experiments and CFD modelling have been carried out at isothermal and combusting conditions. The measurements were obtained at ERC using two component Laser Doppler Velocimetry. To be able to access the inner part of the combustor, the liners of the combustion chamber were outfitted with quartz windows. Temperature measurements were obtained at a few planes using a thermocouple. Modelling of the combustor has been performed using an in-house CFD code. The combustion process has been modelled using a global reaction mechanism and a Flame Generated Manifold reaction mechanism in combination with a presumed PDF model to incorporate the effect of turbulent fluctuations. The Flame Generated Manifold method uses a flame library, which has been generated by performing a number of laminar one-dimensional flame calculations at representative conditions. Comparing the numerical and experimental quite some differences are observed. The CFD model is able to predict the main features of the flow and combustion process, but does not predict the recirculation length accurately. Both combustion models, however, are able to predict the low combustion efficiency measured at the 1atm test condition.

Fuel Injection Scheme for a Compact Afterburner Without Flameholders

2007 ◽  
Author(s):  
Shai Birmaher ◽  
Philipp W. Zeller ◽  
Peter Wirfalt ◽  
Yedidia Neumeier ◽  
Ben T. Zinn
Keyword(s):  
Theoretical Model ◽  
Gas Turbine ◽  
Fuel Injection ◽  
State Of The Art ◽  
Combustion Process ◽  
Operating Conditions ◽  
Experimental Setup ◽  
Turbine Engine ◽  
Theoretical Predictions ◽  
Significant Length

State of the art afterburner combustion employs spray bars and flameholders in a long cavity, which adds significant length and weight to the engine and increases its observability. This paper presents a feasibility study for the development of a compact “prime and trigger” afterburner that eliminates the flameholders and reduces the length of the engine. In this concept, fuel is injected just upstream or in between the turbine stages in such a manner that upon exiting the turbine the fuel has evaporated and premixed with the flow without significant combustion, a process referred to as “priming”. Downstream of the turbine, combustion is initiated either through autoignition or by using a low power plasma radical generator being developed in a parallel investigation to “trigger” the combustion process. The prime and trigger injection and ignition scheme has been investigated using an experimental setup that simulates the operating conditions in a typical gas turbine engine. For this investigation, a trigger is not used, and combustion of the fuel occurs through autoignition. A physics-based theoretical model was developed to predict the location of autoignition for given flow and spray properties and injection locations. The theoretical predictions and the experimental results obtained using thermocouple measurements and CH* chemiluminescence confirm the feasibility of the prime and trigger concept by demonstrating the predictable and controlled autoignition of the afterburner fuel.

Reverse Engineering Gas Turbine Emission Performance: Applied to an Aircraft Auxiliary Power Unit

2010 ◽  
Author(s):  
Christopher C. Leong ◽  
Lucas J. Rye ◽  
Simon Blakey ◽  
Christopher W. Wilson
Keyword(s):  
Reverse Engineering ◽  
Gas Turbine ◽  
Alternative Fuels ◽  
Combustion Process ◽  
Gaseous Emissions ◽  
Emission Data ◽  
Commercial Aviation ◽  
Turbine Engine ◽  
Gaseous Emission ◽  
Future Supply

Environmental and future supply pressures are expected to drive aviation towards alternative fuel sources. However little is available in the literature on aircraft landing-takeoff (LTO) cycle gaseous emissions resulting from the combustion of alternative fuels. Considering the different engine configurations existing in today’s commercial aviation fleet, emission experiments of alternative fuels on all engine types are almost impossible. Modelling may provide a solution but the availability of combustor data (geometry and air split details) in the public domain is limited. A reverse engineering technique is developed to recover the air splits and combustion process in gas turbine engine by a CRN and forward predicting the emissions from the engine exhaust. The model was developed and optimised with a Genetic Algorithm against the Jet A-1 experimental emission data obtained from an APU. Results from the optimised CRN emission predictions closely matched the Jet A-1 gaseous emission data. The modelling technique also successfully demonstrated an ability to predict APU gaseous emission data obtained for Synthetic Paraffinic Kerosene (SPK) (neat and 50–50 blended with Jet A-1) and biodiesel. This technique is expected to enhance the emission databank of aircraft and airside emissions.

scholarly journals МОДЕЛИРОВАНИE ПРОЦЕССА ГОРЕНИЯ В ФАКЕЛЬНЫХ ВОСПЛАМЕНИТЕЛЯХ ГТД

2019 ◽  
pp. 39-49
Author(s):  
Юрий Иванович Торба ◽  
Сергей Игоревич Планковский ◽  
Олег Валерьевич Трифонов ◽  
Евгений Владимирович Цегельник ◽  
Дмитрий Викторович Павленко
Keyword(s):  
Finite Element ◽  
Boundary Conditions ◽  
Computational Model ◽  
Gas Turbine ◽  
Test Bench ◽  
Combustion Process ◽  
Turbine Engines ◽  
Combustion Model ◽  
Gas Turbine Engines ◽  
Turbine Engine

The aim of the work was the development and testing of methods for modeling the combustion process in the torch igniters of gas turbine engines. To achieve it, the finite element method was used. The main results of the work are the substantiation of the need to optimize the torch igniters of gas turbine engines. The practice of operating torch igniters of various designs has shown that the stability of their work depends on the parameters of gas turbine engines and external factors (air and fuel temperature, size of fuel droplets, fuel and air consumption, as well as its pressure). At the same time, the scaling of the geometry of the igniter design does not ensure its satisfactory work in the composition of the GTE with modified parameters. In this regard, an urgent task is to develop a combustion model in a flare igniter to optimize its design. A computational model of a torch igniter for a gas turbine engine of a serial gas-turbine engine in a software package for numerical three-dimensional thermodynamic simulation of AN-SYS FLUENT has been developed. To reduce the calculation time and the size of the finite element model, recommendations on the adaptation of the geometric model of the igniter for numerical modeling are proposed. The mod-els of flow turbulence and combustion, as well as initial and boundary conditions, are selected and substantiated. Verification of the calculation results obtained by comparison of numerical simulation with the data of tests on a specialized test bench was performed. It is shown that the developed computational model makes it possible to simulate the working process in the torch igniters of the GTE combustion chambers of the investigated design with a high degree of confidence. The scientific novelty of the work consists in substantiating the choice of the combustion model, the turbulence model, as well as the initial and boundary conditions that provide adequate results to the full-scale experiment on a special test bench. The developed method of modeling the combustion process in gas turbine torch igniters can be effectively used to optimize the design of igniters based on GTE operation conditions, as well as combustion initialization devices to expand the range of stable operation of the combustion chamber. 

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