Characterizing hydrogen-fuelled pulsating combustion on thermodynamic properties of a combustor

Zhao, Dan; Guan, Yiheng; Reinecke, Arne

doi:10.1038/s42005-019-0142-8

Cited by 111 publications

(22 citation statements)

References 42 publications

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“…The pressure and velocity distribution trends in the three different mesh models are all the same, and the values differ little, all less than 5%. Considering the calculation time and the accuracy of numerical results (Zhao et al 2019;Tang et al 2019), the model with 425,223 grids is adopted.…”

Section: Grid Independence Analysismentioning

confidence: 99%

NO catalytic performance analysis of gasoline engine tapered variable cell density carrier catalytic converter

Zuo

Yang

Zhang

et al. 2021

Environ Sci Pollut Res

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Improving the flow field uniformity of catalytic converter can promote the catalytic conversion of NO to NO2. Firstly, the physical and mathematical models of improved catalytic converter are established, and its accuracy is verified by experiments. Then, the NO catalytic performance of standard and improved catalytic converters is compared, and the influences of structural parameters on its performance are investigated. The results showed that: (1) The gas uniformity, pressure drop and NO conversion rate of the improved catalytic converter are increased by 0.0643, 6.78% and 7.0% respectively. (2) As the cell density combination is 700 cpsi/600 cpsi, NO conversion rate reaches the highest, 73.7%, and the gas uniformity is 0.9821. (3) When the tapered height is 20 mm, NO conversion rate reaches the highest, 72.4%, the gas uniformity is 0.9744. (4) When the high cell density radius is 20 mm, NO conversion rate reaches the highest, 72.1%, the gas uniformity is 0.9783. (5) When the tapered end face radius is 20 mm, NO conversion rate reaches the highest, 72.0%, the gas uniformity is 0.9784. The results will provide a very important reference value for improving NO catalytic and reducing vehicle emission.

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Section: Grid Independence Analysismentioning

confidence: 99%

NO catalytic performance analysis of gasoline engine tapered variable cell density carrier catalytic converter

Zuo

Yang

Zhang

et al. 2021

Environ Sci Pollut Res

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“…Simultaneously, hydrogen, a well-known substitute for many power applications, has the potential to generate clean power whilst ensuring the distribution and storage of large renewable energy sources. However, hydrogen on its own presents disadvantages in combustion systems such as high instabilities [40,41] and flashback potential [42,43], making the use of slower chemicals such as ammonia advantageous to bring down the overall flame speed of H 2 .…”

Section: Work Performed Bymentioning

confidence: 99%

Numerical Predictions of a Swirl Combustor Using Complex Chemistry Fueled with Ammonia/Hydrogen Blends

et al. 2020

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Ammonia, a chemical that contains high hydrogen quantities, has been presented as a candidate for the production of clean power generation and aerospace propulsion. Although ammonia can deliver more hydrogen per unit volume than liquid hydrogen itself, the use of ammonia in combustion systems comes with the detrimental production of nitrogen oxides, which are emissions that have up to 300 times the greenhouse potential of carbon dioxide. This factor, combined with the lower energy density of ammonia, makes new studies crucial to enable the use of the molecule through methods that reduce emissions whilst ensuring that enough power is produced to support high-energy intensive applications. Thus, this paper presents a numerical study based on the use of novel reaction models employed to characterize ammonia combustion systems. The models are used to obtain Reynolds Averaged Navier-Stokes (RANS) simulations via Star-CCM+ with complex chemistry of a 70%–30% (mol) ammonia–hydrogen blend that is currently under investigations elsewhere. A fixed equivalence ratio (1.2), medium swirl (0.8), and confined conditions are employed to determine the flame and species propagation at various operating atmospheres and temperature inlet values. The study is then expanded to high inlet temperatures, high pressures, and high flowrates at different confinement boundary conditions. The results denote how the production of NOx emissions remains stable and under 400 ppm, whilst higher concentrations of both hydrogen and unreacted ammonia are found in the flue gases under high power conditions. The reduction of heat losses (thus higher temperature boundary conditions) has a crucial impact on further destruction of ammonia post-flame, with a raise in hydrogen, water, and nitrogen through the system, thus presenting an opportunity of combustion efficiency improvement of this blend by reducing heat losses. Final discussions are presented as a method to raise power whilst employing ammonia for gas turbine systems.

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“…7(b) shows the corresponding sound energy per unit volume in time domain. Sound energy per unit volume Ea (t) can be calculated as [15]:…”

Section: Further Investigation On Heat Exchanger Effectmentioning

confidence: 99%

Numerical Study of Nonlinear Self-sustained Thermoacoustic Instability in a Swirling Combustor

Sun

Zhao

2020

AIAA Propulsion and Energy 2020 Forum

Self Cite

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Self-exited thermoacoustic instability is undesirable in gas turbines and other propulsion systems due to structural vibration, overheating and flame flashback. Such instability is characterized with large-amplitude limit cycle oscillations. It is typically resulting from the dynamic interaction between turbulence flow-flame-acoustics. A better understanding on the interaction, and an alternative design of effective damping/control approach to stabilize combustors are wanted. In this work, 3D numerical simulations are conducted on a swirling combustor to gain insight on the generation of nonlinear swirling flow-flame-coupled thermoacoustic instability. To capture the turbulence flow-combustion-acoustics interaction, the classical turbulence model for swirling flow RNG k-ε and eddy dissipation concept model with 2-steps are applied. The model is validated first with the experimental data available in the literature. Then it is applied to study the effect of swirling number SN. It is found that increasing the SN leads to the amplitude of combustion instability being increased. The dominant frequency is found to shift to a higher value with increased SN. To attenuate the selfexcited thermoacoustic instability, we propose an alternative passive control approach by implementing a heat exchanger at a pre-selected segment of combustor wall; its temperature TH could be varied. Numerical results show that properly setting TH can attenuate the thermoacoustic instability by approximately 20 dB. The present study contributes to developing a platform to simulate nonlinear thermoacoustic instability in a swirling combustor. It also opens up an alternative control means to prevent the onset or attenuate the undesirable limit cycle oscillations.

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Characterizing hydrogen-fuelled pulsating combustion on thermodynamic properties of a combustor

Cited by 111 publications

References 42 publications

NO catalytic performance analysis of gasoline engine tapered variable cell density carrier catalytic converter

NO catalytic performance analysis of gasoline engine tapered variable cell density carrier catalytic converter

Numerical Predictions of a Swirl Combustor Using Complex Chemistry Fueled with Ammonia/Hydrogen Blends

Numerical Study of Nonlinear Self-sustained Thermoacoustic Instability in a Swirling Combustor

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