Combustor Outlet Research Articles

Effects of Inlet Parameters on Combustion Performance in Gas Turbine Combustor

Abstract The effects of different inlet parameters such as inlet temperature and pressure on combustion performance in a single-head combustor were experimentally investigated in this study. The combustion efficiency, total pressure loss, and CO and NO emissions at the outlet of a single-head rectangular combustor with different types of swirlers were separately measured. The experimental results showed that the inlet parameters had obvious effects on the combustion performance, with critical values of 600 K for the inlet temperature and 3.5 bar for the inlet pressure. The combustion efficiency noticeably increased with an increase in the inlet pressure or temperature below these values; however, when either of the inlet parameters was above the critical value, the combustion efficiency was approximately 100 %; that is, the combustion efficiency changed little with an increase in inlet temperate or pressure. When the inlet temperature or pressure increased, NO emission increased but CO emission decreased. By fitting curves to analyze the experimental data, the empirical relationships between the emissions and the inlet temperature were observed to be $CO\; \propto \;{e^{ - T}}, NO\; \propto \;{e^T}$, and those between the emissions and the inlet pressure were $CO\, \propto \,{e^{a + bP + c{P^2}}}, NO\, \propto \,{e^P}$. The total pressure loss increased with the inlet temperature.

Effect of Airflow Temperature on the Formation of Initial Flame Kernel and the Propagation Characteristics of Flame

Using liquid RP-3 aviation kerosene as the fuel to study, the effect of airflow temperature on the formation of initial flame kernel during the ignition of spray combustion and on the propagation characteristics of flame was investigated. Combining high-speed camera and dynamic temperature acquisitions at the outlet of combustor, the internal triggering mode was used under a constant fuel flow rate and airflow velocity. This combined system simultaneously recorded the formation of initial flame kernel, flame propagation, and outlet temperature variation of combustor under different airflow temperatures. MATLAB software was used to obtain the reaction zones at different moments and to analyze the effects of airflow temperature on morphological characteristics such as flame area, perimeter-to-area ratio, maximum length-to-height ratio, equivalent mean length-to-height ratio, mass center, and centroid. According to the growth rate in flame area, the ignition process can be divided into three stages: formation of flame kernel, rapid development of flame, and stable development of flame. Airflow temperature not only affects the formation time of flame kernel but also affects the growth rate of flame area. During the development of flame, the movements of mass center and centroid are irregular, and their positions do not coincide with each other. However, the overall moving trends are consistent. With the increase of the airflow temperature, the position, where the flame kernel is gradually formed, moves closer to the center of the end face of spark plug. The force of airflow on flame is the main factor that increases the flame area and heat-release rate. Therefore, the folds around the flame edge mainly result from the stretching under the action of airflow. With the increase in airflow temperature, the heat release of the initial flame kernel increases, and the ratio of perimeter to area as a characterization parameter increases by 8%, 86%, and 33%, respectively. In addition, the maximum outlet temperature rise increased by about 53%, 73.5%, and 0.65%, respectively. Meanwhile, the maximum rate of temperature rise increased by about 42.8%, 57%, and 5.1%, respectively.

Impact of Predicted Combustor Outlet Conditions on the Aerothermal Performance of Film-Cooled High Pressure Turbine Vanes

Turbine inlet conditions in lean-burn aeroengine combustors are highly swirled and present nonuniform temperature distributions. Uncertainty and lack of confidence associated with combustor-turbine interaction affect significantly engine performance and efficiency. It is well known that only Large-eddy and scale-adaptive simulations (SAS) can overcome the limitations of Reynolds-averaged Navier–Stokes (RANS) in predicting the combustor outlet conditions. However, it is worth investigating the impact of such improvements on the predicted aerothermal performance of the nozzle guide vanes (NGVs), usually studied with RANS-generated boundary conditions. Three numerical modelling strategies were used to investigate a combustor-turbine module designed within the EU Project FACTOR: (i) RANS model of the NGVs with RANS-generated inlet conditions; (ii) RANS model of the NGVs with scale-adaptive simulation (SAS)-generated inlet conditions; (iii) SAS model inclusive of both combustor and NGVs. It was shown that estimating the aerodynamics through the NGVs does not demand particularly complex approaches, in contrast to situations where turbulent mixing is key. High-fidelity predictions of the turbine entrance conditions proved very beneficial to reduce the discrepancies in the estimation of adiabatic temperature distributions. However, a further leap forward can be achieved with an integrated simulation, capable of reproducing the transport of unsteady fluctuations generated from the combustor through the turbine, which play a key role in presence of film cooling. This work, therefore, shows how separate analysis of combustor and NGVs can lead to a poor estimation of the thermal loads and ultimately to a wrong thermal design of the cooling system.

Numerical Study of the Axial Gap and Hot Streak Effects on Thermal and Flow Characteristics in Two-Stage High Pressure Gas Turbine

Combined cycle power plants (CCPPs) are becoming more important as the global demand for electrical power increases. The power and efficiency of CCPPs are directly affected by the performance and thermal efficiency of the gas turbines. This study is the first unsteady numerical study that comprehensively considers axial gap (AG) in the first-stage stator and first-stage rotor (R1) and hot streaks in the combustor outlet throughout an entire two-stage turbine, as these factors affect the aerodynamic performance of the turbine. To resolve the three-dimensional unsteady-state compressible flow, an unsteady Reynolds-averaged Navier–Stokes (RANS) equation was used to calculate a k − ω SST γ turbulence model. The AG distance d was set as 80% (case 1) and 120% (case 3) for the design value case 2 (13 mm or d/Cs1 = 0.307) in a GE-E3 gas turbine model. Changes in the AG affect the overall flow field characteristics and efficiency. If AG decreases, the time-averaged maximum temperature and pressure of R1 exhibit differences of approximately 3 K and 400 Pa, respectively. In addition, the low-temperature zone around the hub and tip regions of R1 and second-stage rotor (R2) on the suction side becomes smaller owing to a secondary flow and the area-averaged surface temperature increases. The area-averaged heat flux of the blade surface increases by a maximum of 10.6% at the second-stage stator and 2.8% at R2 as the AG decreases. The total-to-total efficiencies of the overall turbine increase by 0.306% and 0.295% when the AG decreases.

Gas Turbine Fouling: A Comparison Among 100 Heavy-Duty Frames

Over recent decades, the variability and high costs of the traditional gas turbine fuels (e.g., natural gas) have pushed operators to consider low-grade fuels for running heavy-duty frames. Synfuels, obtained from coal, petroleum, or biomass gasification, could represent valid alternatives in this sense. Although these alternatives match the reduction of costs and, in the case of biomass sources, would potentially provide a CO2 emission benefit (reduction of the CO2 capture and sequestration costs), these low-grade fuels have a higher content of contaminants. Synfuels are filtered before the combustor stage, but the contaminants are not removed completely. This fact leads to a considerable amount of deposition on the nozzle vanes due to the high temperature value. In addition to this, the continuous demand for increasing gas turbine efficiency determines a higher combustor outlet temperature. Current advanced gas turbine engines operate at a turbine inlet temperature (TIT) of (1400–1500) °C, which is high enough to melt a high proportion of the contaminants introduced by low-grade fuels. Particle deposition can increase surface roughness, modify the airfoil shape, and clog the coolant passages. At the same time, land-based power units experience compressor fouling, due to the air contaminants able to pass through the filtration barriers. Hot sections and compressor fouling work together to determine performance degradation. This paper proposes an analysis of the contaminant deposition on hot gas turbine sections based on machine nameplate data. Hot section and compressor fouling are estimated using a fouling susceptibility criterion. The combination of gas turbine net power, efficiency, and TIT with different types of synfuel contaminants highlights how each gas turbine is subjected to particle deposition. The simulation of particle deposition on 100 gas turbines ranging from 1.2 MW to 420 MW was conducted following the fouling susceptibility criterion. Using a simplified particle deposition calculation based on TIT and contaminant viscosity estimation, the analysis shows how the correlation between type of contaminant and gas turbine performance plays a key role. The results allow the choice of the best heavy-duty frame as a function of the fuel. Low-efficiency frames (characterized by lower values of TIT) show the best compromise in order to reduce the effects of particle deposition in the presence of high-temperature melting contaminants. A high-efficiency frame is suitable when the contaminants are characterized by a low-melting point thanks to their lower fuel consumption.

Analysis of air-staged combustion of NH3/CH4 mixture with low NOx emission at gas turbine conditions in model combustors

The NOx formation characteristics have been numerically investigated in the NH3/CH4 fired model combustor consisting of perfectly stirred reactors (PSR) and plug flow reactors (PFR) with 84-species Tian mechanism at gas-turbine relevant conditions of 23 atm and 1873 K at the combustor outlet. Specifically, the impacts of NH3 dilution on NOx formation were first studied in a non-staged model combustor consisting of one PSR representing main combustion zone and one PFR representing post-combustion zone over a wide range of the volumetric ratio of NH3 in the NH3/CH4 fuel. It was found that the NOx emission increases sharply with the NH3 addition mainly through the enhanced HNO pathway in the main reaction zone. Recognizing that the NOx formation via the HNO pathway is limited by the availability of oxygen, the effects of fuel/air equivalence ratio on NOx formation were then quantified under different levels of NH3 dilution. It was revealed that at fuel-rich conditions, the NOx formation via HNO pathway can be offset by the reduction via other pathways, such as pathways related to NHi, leading to the overall low NOx emission. Finally, an air-staged model combustion system was proposed, in which the equivalence ratio in the primary stage was chosen to be 1.5 to take advantage of the low NOx emission under fuel-rich conditions. The air split among the two stages was determined by the fixed outlet temperature of 1873 K. A parametric study demonstrated that less than 30 ppm NOx emission can be achieved with simple two-stage combustion even when the volumetric ratio of the NH3 reaches 40%, which is dramatically lower than the one of thousands ppm in the non-staged combustion. The results were further verified with the 47-species Konnov mechanism, demonstrating the great potential of air-staged combustion for low NOx emission in the NH3/CH4 fired combustion.

Numerical Investigation of Influence of Multi-Line Fuel Injection (Methane) on a Tubular Combustor Emissions of Micro Gas Turbine

This work presents a technique for design optimization of a gas turbine tubular combustor. This technique is based on the use of computational fluid dynamics (CFD) with CFX solver to reduce emission gases by using multi-line of fuel injection in secondary zone. This research relates the mass fraction of the multi-line of fuel injection as well as the equivalence ratio of the tubular combustion chamber designed for methane fuel. By using k-ε as turbulent model and Probability Density Function (PDF) Flamelet as combustion model. The operating casing data of micro size gas turbine are used, the validation of fuel flow mixing and combustion analyses were carried out with a focus on species concentration in the combustor outlet section. With variant fuel mass flow rate fraction in fuel lines (F2/F1), It was found that, with the new design NO reduced about 56% for the mass fraction 3 in high equivalence ratio and about 30%for the mass fraction 1 for a low equivalence ratio, while reduction in outlet temperature profile (pattern factor) is about 45% → 35%.

Investigation on the combustion performance enhancement of the premixed methane/air in a two-step micro combustor

After a two-step global reaction mechanism is used to compute the chemical reactions of the reacting flows, a premixed methane/air combustion model of a two-step micro combustor is established based on some effect factors such as step angle, wall materials and inlet velocity. Moreover, the three or four kinds of the micro two-step combustors are used to investigate the effect of flame shape in the micro-channel, temperature characteristic, velocity field on the premixed methane combustion and field synergetic degree of the premixed methane/air combustion. It’s shown that a suitable step angle and inlet velocity are very useful for enhancing the stability of methane premixed combustion of the two-step micro combustor, and the methane premixed combustion of the two-step micro combustor is also influenced by the wall matericals. Average temperatures of the outlet and combustion efficiencies of the two-step micro combustor at different inlet velocities are verified by the measurement results. It’s shown that there are good comprehensive performance and higher synergy degree of the two-step micro combustor at the inlet velocities of 2 m/s and 4 m/s, and there are more and more obvious differences between combustion efficiency after field synergy and original combustion efficiency when the inlet velocities are increased.

Combustion characteristics of a non-premixed methane flame in a generated burner under distributed combustion conditions: A numerical study

Distributed combustion is a novel technique in providing of thermal field uniformity over the entire of the combustor and in reducing of pollutant emissions. This study concentrates on combustion characteristic of a non-premixed methane flame for the newly generated burner under conventional and distributed combustion conditions. The non-premixed methane flame has been modelled by using a computational fluid dynamics commerce code. In the modellings, standard k-Ɛ turbulence model, the non-premixed modeling with and assumed-shape that is β -function Probability Density Function and P-1 radiation model have been used. The predicted temperature distributions have been compared with the experimental data under conventional combustion conditions and it has been determined that the predicted results are in good agreement with the measured temperature values. The predicted results show that distributed combustion enables more uniform thermal field under distributed combustion conditions in the combustor. In particular, it has been demonstrated that the temperature of the methane flame has been reduced significantly. When the effect of distributed combustion on pollutant emissions is evaluated, it has been concluded that NOX and CO emissions have been reduced down to nearly zero emissions while CO2 emission levels have been increased slightly at the combustor outlet under distributed combustion conditions.

Numerical investigation of a combined solid fuel scramjet combustor

A new scramjet configuration using solid fuel as propellant is proposed, namely, the combined solid fuel scramjet. The combined solid fuel scramjet combustor has been investigated numerically to predict its characteristics. Two-dimensional axisymmetric Reynolds-averaged Navier–Stokes equations and species transport equations are solved numerically. Turbulence closure is achieved using the shear stress transport k-ω model. Three global one-step reaction mechanisms are used in this study. The experimental data in the published literature has been used to validate the accuracy of numerical model. The results of the numerical analysis show that secondary combustion occurs in the supersonic combustor. At the combustor outlet, the total pressure loss is about 0.65 and the combustion efficiency is about 48%. A subsonic recirculation zone is formed near the wall between the air inlet and the fuel-rich gas inlet, which is beneficial to mixing and flame holding. A normal shock wave is generated at the end of the expansion zone after the fuel-rich gas is injected into the combustor, and this is due to the strong pressure downstream induced by secondary combustion.

Catalytic combustion in a plate type combustor to achieve uniform temperature distribution

Optimization of a catalytic combustor constructed using thin honeycomb ceramic substrates is reported herein. Honeycomb ceramic catalytic combustor is capable of providing heat to a dimethyl ether (DME) reformer, which is an essential requirement for an endothermic reforming process. The function of the proposed catalytic combustor is to maintain a uniform temperature distribution up to 500 °C. A fixed-bed flow reactor type combustor was set to operate under atmospheric pressure, and Pt/γ-Al2O3 catalyst was coated on the cordierite substrate (600 cell per square inch(cpsi)). Experimental variables considered in this study include the composition of multi-catalyst blocks, flow distributor, excess air ratio, space velocity, exit area ratio of the burner, and type of fuel. While performing the parametric study, the space velocity was selected in the range of 18000-27000 h-1 to ensure stable combustion (root mean square error (RMSE) < 10). For catalytic combustors employing C3H8 as fuel, optimized T-shaped and SiC foam distributors comprising three catalyst blocks with 50 % minimum area ratio of the combustor outlet were deemed as the best design combination in terms of superior combustion performance with temperature uniformity and no exhaust pollutants. For catalytic combustors fueled with DME, temperature variation on the surface of the combustor could be maintained within 17.6 °C of the reference temperature value.

International Experience in Developing Low-Emission Combustors for Land-Based, Large Gas-Turbine Units: Mitsubishi Heavy Industries’ Equipment

This is the second paper in a series of publications summarizing the international experience in the development of low-emission combustors (LEC) for land-based, large (above 250 MW) gas-turbine units (GTU). The purpose of this series is to generalize and analyze the approaches used by various manufacturers in designing flowpaths for fuel and air in LECs, managing fuel combustion, and controlling the fuel flow. The efficiency of advanced GTUs can be as high as 43% (with an output of 350–500 MW) while the efficiency of 600–800 MW combined-cycle units with these GTUs can attain 63.5%. These high efficiencies require a compression ratio of 20–24 and a temperature as high as 1600°С at the combustor outlet. Accordingly, the temperature in the combustion zone also rises. All the requirements for the control of harmful emissions from these GTUs are met. All the manufacturers and designers of LECs for modern GTUs encounter similar problems, such as emissions control, combustion instability, and reliable cooling of hot path parts. Methods of their elimination are different and interesting from the standpoint of science and practice. One more essential requirement is that the efficiency and environmental performance indices must be maintained irrespective of the fuel composition or heating value and also in operation at part loads below 40% of rated. This paper deals with Mitsubishi Series M701 GTUs, F, G, or J class, which have gained a good reputation in the power equipment market. A design of a burner for LECs and a control method providing stable low-emission fuel combustion are presented. The advantages and disadvantages of the use of air bypass valves installed in each liner to maintain a nearly constant air to fuel ratio within a wide range of GTU loads are described. Methods for controlling low- and high-frequency combustion instabilities are outlined. Upgrading of the cooling system for the wall of a liner and a transition piece is of great interest. Change over from effusion (or film) cooling to convective steam cooling and convective air cooling has considerably increased the GTU efficiency.

Influence of the pressure side injection slot on the cooling performance of endwall surface

ABSTRACTIn modern gas turbine engines, the first stage vane endwall endures high thermal load with the increase of the turbine inlet temperature and the uniformity of the temperature distribution at combustor outlet. Moreover, the endwall secondary flow forces the coolant flow toward the suction side, resulting in hot regions along the pressure side endwall. In the worst case, hot regions lead to thermal failure. In order to ensure that the gas turbine operates safely, advanced cooling techniques are urgently needed to be implemented to reduce the hot regions along the pressure side endwall. In the current research, the influences of the pressure side injection slot on the film cooling performance of the endwall surface were numerically investigated. The three-dimensional Reynolds-averaged Navier-Stokes (RANS) equations combined with the shear stress transport (SST) turbulence model were solved to conduct the simulations. Cases with different injection slot configurations have been simulated. The results indicate that the hot region along the pressure side endwall is significantly reduced by introducing the pressure side injection slot. The coolant from the pressure side injection slot is assisted by the pressure side vertical flow toward the adjacent vane suction side. Therefore, the coolant coverage and the cooling effectiveness are increased. In this study, the expanded slot (ES) achieves a larger cooling effectiveness than the normal slot (NS) and convergent slot (CS) at a small blowing ratio M = 0.5. In contrast, the CS obtains a larger cooling effectiveness than the NS and ES at M = 1.0 and M = 1.5. In addition, the introduction of the pressure side injection slot has a small influence on the aerodynamic performance of the vane cascade.

A Real-Time Combustion Instability Simulation with Comprehensive Thermo-Acoustic Dynamic Model

The thermo-acoustic instability in the combustion process of a gas turbine is caused by the interaction of the heat release mechanism and the pressure perturbation. These acoustic vibrations cause fatigue failure of the combustor and decrease the combustion efficiency. This study aims to develop a segmented dynamic thermo-acoustic model to understand combustion instability of a gas turbine. Then, the combustion instability was designed using the acoustic heat release model, and the designed instability model was segmented using the finite difference method, to evaluate the characteristics of flame propagation at each node. The combustion instability model was validated using experimental data to verify the instability amplitude. Also, the optimal node number was determined using the adiabatic flame temperature response. 10 nodes were selected in this study. A sensitivity analysis showed the predicted instability amplitude decreased when the nodes increased until node 4, due to heat generation. However, above 4 nodes the amplitude decreased, since the combustion outlet was directly connected to the ambient. As a result, the segmented combustion instability model was able to evaluate the flame propagation characteristics more accurately and found the largest area of instability was near the flame area.

Numerical Investigation of the Impact of the Compressor Operation Mode on Working Process of the Combustion Chamber

The method of integrated compressor/combustor simulation was used to investigate the impact of flow distortion, appeared due to compressor blades, during the combustion chamber workflow. The method was improved in terms of generating a common grid and of principles of the boundary conditions settings. The geometric model includes four geometric volume bodies: guide vanes of the penultimate stage of high-pressure compressor, the impeller and guide vanes of the last stage and the flow path of combustion chamber. The calculation was carried out for some operation mode of the engine (nominal, 0.7 of nominal and 0.5 of nominal regimes) with and without compressor. The results were compared with the results of combustion chamber simulation without the compressor. Simulations showed that blade wakes extend up to the flame tube head. These wakes influence on the flame tongue, pressure field, temperature and velocity in the recirculation-mixing zone. It can influence on combustion efficiency, ecological performance and on temperature field at the combustor outlet. Thus, the simulations, which take into account combustion chamber and compressor, are more fully represent the characteristics of the working process of the combustion chamber and increase the efficiency of the design of new products.

Emission characteristics of aviation kerosene combustion in aero-engine annular combustor with low temperature plasma assistance

A plasma-assisted combustion test platform for annular combustor was developed to validate the feasibility of using plasma-assisted combustion actuation to reduce emission levels. Combustor outlet temperature and emission levels of O2, CO2, H2, CO, and NOx were measured by using a thermocouple and a Testo 350-Pro Flue Gas Analyzer, respectively. Combustor combustion efficiency was also calculated. The effects of duty ratio, feedstock air-flow rate, and actuator position on combustion efficiency and emission performance have been analyzed. The results show that the target of CO and NOx emissions reduction in plasma-assisted combustion could not be fully achieved for kerosene/air mixture with different combustor excessive air coefficients. It is also shown that plasma-assisted combustion with dilution air hole actuation is superior to that of secondary air hole actuation for the combustion of liquid-kerosene fuel. Besides, plasma-assisted combustion effect is more obvious with an increase of duty ratio or feedstock air-flow rate. These results are valuable for the future optimization of kerosene-fueled aero-engine when using plasma-assisted combustion devices to improve emission performance of annular combustor.

The effects of internal leakage on the performance of a micro gas turbine

Micro gas turbines are manufactured to have a compact structure and small volume, which makes them more vulnerable to internal leakages compared to heavy-duty gas turbines. Accordingly, precise diagnosis of the performance degradation in a micro gas turbine is important. This study investigates the characteristics of degradation. Performance maps were used for the compressor and turbine, and a multi-segment counter-flow heat exchanger model was used for the recuperator. The component models were refined using actual operation data, resulting in precise simulation of the reference operation without leakage. A performance analysis was carried out, and the results were analyzed for three types of leakage with the following paths: from the compressor outlet to the recuperator’s cold-side outlet, from the compressor outlet to the combustor outlet, and from the combustor inlet to the turbine outlet. The third path produced the largest reduction in engine efficiency. The degradations were also compared with those related to compressor fouling and turbine erosion, which are the most common causes of degradation in a gas turbine. Even when qualitatively similar performance changes were observed, the root cause could be determined by analyzing differences in performance parameters such as the fuel flow.

Comparative analysis of hydrogen/air combustion CFD-modeling for 3D and 2D computational domain of micro-cylindrical combustor

A computational study of a micro-cylindrical premixed hydrogen-air combustor using RANS is presented. The influence of the geometric dimensionality of the computational domain is studied by performing numerical simulations with 2D planar, 2D axisymmetric and 3D meshes. A commercial software package with a particular choice of several physical models (regarding turbulence, combustion, radiation) is used for this analysis. A mathematical model describing the hydrogen/air combustion in a cylindrical combustor is developed. The reaction scheme of combustion process with 9 species and 19 steps was simulated by usage Eddy Dissipation Concept (EDC) model. The obtained results from presented CFD model were compared with experimental and numerical data of other publications. The combustion characteristics of developed numerical model such as wall and fluid temperature, hydrogen mass fraction, velocity and pressure were investigated for different geometry types. It is established that the 2D approach to solving combustion problems leads to significant deviations of the obtained results from real ones and can be used only for a preliminary evaluation of the characteristics of the combustion process. Based on the developed model, it is established that the difference between the combustion products temperature at the combustor outlet for the three- and two-dimensional (2D-planar and 2D-axis) geometries is more than 25%, and for the range of the flame formation the temperatures differ by several times. The contours of pressure have minimal visual differences for the all hydrogen burning characteristics that are investigated in this work. The axial pressure profiles for all investigated geometries (2D-axis, 2D-planar and 3D) are almost similar in terms of trend and value.

On computation of solid fuel regression rate in ramjet combustor

Development of a solid fuel ramjets requires mathematical modeling of the solid fuel regression inside a combustor with accounting of solid fuel gasification and combustion processes and a numerical method to calculate parameters of these processes. This report presents a quasi-one-dimensional model of processes inside the solid fuel ramjet combustor. The model allows to calculate the solid fuel regression rate and gas flow parameters at the combustor outlet while air flow parameters at the combustor inlet are fixed. The model is based on mass, energy, species and momentum conservation equations and deals with thermochemical processes inside the ramjet combustor. It considers gas flow inside the combustor, gasified fuel combustion, convective heat transfer, solid fuel pyrolysis kinetics. The model is verified by comparison of the numerical results with the experimental data available from other authors. The analysis of the numerical results shows a dependence of the flow structure and thermochemical parameters of a solid fuel employed on the regression rate.

Development of a fast evaluation tool for rotating detonation combustors

• Reduced modeling of rotating detonation combustors. • Prediction of the combustor performance in function of the inlet conditions. • Prediction of the radius to detonation height ratio for minimum entropy. Although rotating detonation engines may lead to improvements in the cycle thermal efficiency, their overall optimization is currently constrained by the need to perform time-consuming three-dimensional Navier–Stokes simulations of the combustor. Thus, there is a critical need to establish fast models to calculate the time-dependent temperature and pressure at the combustor outlet for further engine analysis and turbine integration. This manuscript describes a fast 2D simulation code of a rotating detonation combustor. This numerical methodology uses a 1D chemical kinetics solver, to reproduce the change of properties across the detonation wave front. The post-detonation flow is then resolved using a method of characteristics, which allows the prediction of pressure and temperature gain across the combustor. The main flow pattern, including the detonation front features, the shock wave angle and the outlet properties were compared with the solution of a two-dimensional Unsteady Reynolds Averaged Navier–Stokes solver. This approach is subsequently used to predict the detonation height based on the entropy generation across the combustor.