Multi-stage nozzle-shape optimization for pulsed hydrogen–air detonation combustor

Ornano, Francesco; Braun, James; Saracoglu, Bayindir H.; Paniagua, Guillermo

doi:10.1177/1687814017690955

Cited by 10 publications

(2 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Several detonation engine architectures exist. A first one is a pulse detonation combustors (PDC) in which a cyclic refill occurs in a tube [4]. Another architecture is a rotating detonation combustor (RDC) in which a rotating shock continuously burns the fuel.…”

Section: Introductionmentioning

confidence: 99%

Design, Optimization, and Analysis of Supersonic Radial Turbines

Inhestern

Braun

Paniagua

et al. 2020

Journal of Engineering for Gas Turbines and Power

Self Cite

View full text Add to dashboard Cite

New compact engine architectures such as pressure gain combustion require ad hoc turbomachinery to ensure an adequate range of operation with high performance. A critical factor for supersonic turbines is to ensure the starting of the flow passages, which limits the flow turning and airfoil thickness. Radial outflow turbines inherently increase the cross section along the flow path, which holds great potential for high turning of supersonic flow with a low stage number and guarantees a compact design. First, the preliminary design space is described. Afterward a differential evolution multi-objective optimization with 12 geometrical design parameters is deducted. With the design tool autoblade 10.1, 768 geometries were generated and hub, shroud, and blade camber line were designed by means of Bezier curves. Outlet radius, passage height, and axial location of the outlet were design variables as well. Structured meshes with around 3.7 × 106 cells per passage were generated. Steady three-dimensional (3D) Reynolds-averaged Navier–Stokes (RANS) simulations, enclosed by the k-omega shear stress transport turbulence model were solved by the commercial solver CFD++. The geometry was optimized toward low entropy and high-power output. To prove the functionality of the new turbine concept and optimization, a full wheel unsteady RANS simulation of the optimized geometry exposed to a nozzled rotating detonation combustor (RDC) has been performed and the advantageous flow patterns of the optimization were also observed during transient operation.

show abstract

Section: Introductionmentioning

confidence: 99%

Design, Optimization, and Analysis of Supersonic Radial Turbines

Inhestern

Braun

Paniagua

et al. 2020

Journal of Engineering for Gas Turbines and Power

Self Cite

View full text Add to dashboard Cite

show abstract

“…Currently, RDCs are numerically examined with computationally-expensive Euler [8,9] or unsteady Reynolds-averaged Navier-Stokes solvers [10], where the injection process is either modeled as premixed mixture or as non-premixed flow. The detonation process can be modeled in several ways: using one-step reaction kinetics [11] with a limited number of species; or with two-step chemical reaction models [12]; or with an induction parameter which allows for larger grid size and time steps [13][14][15][16]; or with detailed reaction kinetics [17] which lead to expensive computations. Due to the use of a coarse computational grid, most of the Navier-Stokes (URANS) simulations cannot resolve the boundary layer with sufficient accuracy to predict the actual convective heat-transfer level.…”

mentioning

confidence: 99%

Numerical Assessment of the Convective Heat Transfer in Rotating Detonation Combustors Using a Reduced-Order Model

2018

Self Cite

View full text Add to dashboard Cite

The pressure gain across a rotating detonation combustor offers an efficiency rise and potential architecture simplification of compact gas turbine engines. However, the combustor walls of the rotating detonation combustor are periodically swept by both detonation and oblique shock waves at several kilohertz, disrupting the boundary layer, resulting in a rather complex convective heat transfer between the fluid and the solid walls. A computationally fast procedure is presented to calculate this extraordinary convective heat flux along the detonation combustor. First, a numerical model combining a two-dimensional method of characteristics approach with a monodimensional reaction model is used to compute the combustor flow field. Then, an integral boundary layer routine is used to predict the main boundary layer parameters. Finally, an empirical correlation is adopted to predict the convective heat-transfer coefficient to obtain the bulk and local heat flux. The procedure has been applied to a combustor operating with premixed hydrogen-air fuel. The results of this approach compare well with high-fidelity unsteady Reynolds-averaged Navier-Stokes three-dimensional simulations, which included wall refinement in an unrolled combustor. The model demonstrates that total pressure has an important influence on heat flux within the combustor and is less dependent on the inlet total temperature. For an inlet total pressure of 0.5 MPa and an inlet total temperature of 300 K, a peak time-averaged heat flux of 6 MW/m 2 was identified at the location of the triple point, followed by a decrease downstream of the oblique shock, to about 4 MW/m 2 . Maximum discrepancy between the reduced-order model and the high-fidelity solver was 16%, but the present reduced-order model required a computational time of only 200 s, that is, about 7000 times faster than the high-fidelity three-dimensional unsteady solver. Therefore, the present tool can be used to optimize the combustor cooling system. Therefore, it is critical to perform a detailed analysis of the convective heat transfer and develop predictive tools that allow a preliminary design of the cooling system. To address this issue, we present a reduced-order model that predicts the convective heat transfer in a rotating detonation combustor (RDC) with a numerical approach that is three orders of magnitude faster than three-dimensional unsteady Reynolds-averaged solvers.RDCs have been experimentally tested, for example, in the US [2-4], Japan [5], Russia [6] and France [7]. The tests uncovered enormous heat-flux release threatening the integrity of the combustor and limiting its runtime to fractions of a second. The thermal optimization of these combustors is constrained by the availability of precise and time-effective thermal solvers that can evaluate the thermal performance in a timely manner. Currently, RDCs are numerically examined with computationally-expensive Euler [8,9] or unsteady Reynolds-averaged Navier-Stokes solvers [10], where the injection process is either modeled as p...

show abstract

The efficiency of a pulsed detonation combustor–axial turbine integration

Xisto

Petit

Grönstedt

et al. 2018

Aerospace Science and Technology

Self Cite

View full text Add to dashboard Cite

The paper presents a detailed numerical investigation of a pulsed detonation combustor (PDC) coupled with a transonic axial turbine stage. The time-resolved numerical analysis includes detailed chemistry to replicate detonation combustion in a stoichiometric hydrogenair mixture, and it is fully coupled with the turbine stage flow simulation. The PDC-turbine performance and flow behaviour are analyzed for different power input conditions, by varying the system purge fraction. Such analysis allows for the establishment of cycle averaged performance data and also to identify key unsteady gas dynamic interactions occurring in the system. The results obtained allow for a better insight on the source and effect of different loss mechanisms occurring in the coupled PDC-turbine system. One key aspect arises from the interaction between the non-stationary PDC outflow and the constant rotor blade speed. Such interaction results in pronounced variations of rotor incidence angle, penalizing the turbine efficiency and capability of generating a quasi-steady shaft torque. . Please refer to any applicable publisher terms of use.concepts. The European Ultra Low emission Technology Innovations for Mid-century Air-4 craft Turbine Engines (ULTIMATE) [1] addresses the prime gas turbine engine loss sources, 5 revealed by exergetic analysis [2], and investigates possible synergies arising from the combi-6 nation of radical technologies. One of the investigated gas turbine engine concepts comprises 7 an intercooled geared turbofan including a pulse detonation combustion (PDC) system [3]. 8 Pulsed detonation combustors burn fuel using an intermittent, periodically initiated, 9 detonation wave combining heat addition with a pressure increase. This should theoretically 10 result in a lower entropy increase than the conventional Joule-Brayton cycle. Pressure rise 11 combustion systems are believed to provide a theoretical improvement of 8 to 15% [3, 4, 5] 12 in the thermal efficiency of the power plant. 13Among many other very important engineering challenges, the theoretical potential of 14 integrating pulsed detonation combustion in a gas turbine is dependent on efficient integra-15 tion with a upstream compressor [6] and a downstream expansion system [7, 8, 9, 10, 11, 12]. 16The unsteady nature of pulsed detonation results in strong variations in mass flow, thermo-17 dynamic quantities, turbine rotor inlet angles [13], and can even lead to periods of reversed 18 flow [14]. The turbine is therefore subjected to rapid periodic changes in operating con-19 ditions and cannot be represented by a single point in a performance map [15]. This flow 20 behavior has a direct negative impact on the high pressure turbine efficiency, and can negate 21 the theoretical thermal efficiency improvements of detonation combustion. Moreover, irre-22 spective of the turbomachinery concept being investigated it is important to understand 23 how the non-stationary PDC shock-waves [16, 17], influence turbomachinery flows, in par-24 ticular during the early...

show abstract

Multi-stage nozzle-shape optimization for pulsed hydrogen–air detonation combustor

Cited by 10 publications

References 17 publications

Design, Optimization, and Analysis of Supersonic Radial Turbines

Design, Optimization, and Analysis of Supersonic Radial Turbines

Numerical Assessment of the Convective Heat Transfer in Rotating Detonation Combustors Using a Reduced-Order Model

The efficiency of a pulsed detonation combustor–axial turbine integration

Contact Info

Product

Resources

About