Investigation of counter-rotating shock wave and wave direction control of hollow rotating detonation engine with Laval nozzle

Rong, Guangyao; Cheng, Miao; Sheng, Zhaohua; Li, Xiangyang; Yunzhen, Zhang; Wang, Jianping

doi:10.1063/5.0089207

Cited by 59 publications

(3 citation statements)

References 55 publications

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“…"Grid independence" means that in numerical simulation, the simulation results are unaffected by grid resolution and shape; the simulation results obtained on different grids are similar. Grid independence verification is performed by changing the grid size [50][51][52]. Only the grid size is reversed, keeping other conditions unchanged, and the number of grids obtained in turn is 3,998,126, 4,430,126, 5,150,126, and 6,350,126.…”

Section: Grid Independence Verificationmentioning

confidence: 99%

Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

Yang,

Lee,

Lee

2024

CMES

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Cavitation is a common issue in pumps, causing a decrease in pump head, a fall in volumetric efficiency, and an intensification of outlet flow pulsation. It is one of the main hazards that affect the regular operation of the pump. Research on pump cavitation mainly focuses on mixed flow pumps, jet pumps, external spur gear pumps, etc. However, there are few cavitation studies on external herringbone gear pumps. In addition, pumps with different working principles significantly differ in the flow and complexity of the internal flow field. Therefore, it is urgent to study the cavitation characteristics of external herringbone gear pumps. Compared with experimental methods, visual research and cavitation area identification are achieved through computation fluid dynamic (CFD), and changing the boundary conditions and shape of the gear rotor is easier. The simulation yields a head error of only 0.003% under different grid numbers, and the deviation between experimental and simulation results is less than 5%. The study revealed that cavitation causes flow pulsation at the outlet, and the cavitation serious area is mainly distributed in the meshing gap and meshing area. Cavitation can be inhibited by reducing the speed, increasing the inlet pressure, and changing the helix angle can be achieved. For example, when the inlet pressure is 5 bar, the maximum gas volume fraction in the meshing area is less than 50%. These results provide a reference for optimizing the design and finding the optimal design parameters to reduce or eliminate cavitation.

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Section: Grid Independence Verificationmentioning

confidence: 99%

Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

Yang,

Lee,

Lee

2024

CMES

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“…Other studies have investigated hydrogen production systems using photovoltaic cells and polymer membrane electrolyzers [ 21 , 22 , 23 , 24 ]. Scamman et al [ 25 ] investigated the combination of solar energy systems using photovoltaic cells and polymer membrane electrolyzers in three weather conditions.…”

Section: Introductionmentioning

confidence: 99%

Thermodynamics Investigation and Artificial Neural Network Prediction of Energy, Exergy, and Hydrogen Production from a Solar Thermochemical Plant Using a Polymer Membrane Electrolyzer

Jery

Salman

Al-Khafaji³

et al. 2023

Molecules

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Hydrogen production using polymer membrane electrolyzers is an effective and valuable way of generating an environmentally friendly energy source. Hydrogen and oxygen generated by electrolyzers can power drone fuel cells. The thermodynamic analysis of polymer membrane electrolyzers to identify key losses and optimize their performance is fundamental and necessary. In this article, the process of the electrolysis of water by a polymer membrane electrolyzer in combination with a concentrated solar system in order to generate power and hydrogen was studied, and the effect of radiation intensity, current density, and other functional variables on the hydrogen production was investigated. It was shown that with an increasing current density, the voltage generation of the electrolyzer increased, and the energy efficiency and exergy of the electrolyzer decreased. Additionally, as the temperature rose, the pressure dropped, the thickness of the Nafion membrane increased, the voltage decreased, and the electrolyzer performed better. By increasing the intensity of the incoming radiation from 125 W/m2to 320 W/m2, the hydrogen production increased by 111%, and the energy efficiency and exergy of the electrolyzer both decreased by 14% due to the higher ratio of input electric current to output hydrogen. Finally, machine-learning-based predictions were conducted to forecast the energy efficiency, exergy efficiency, voltage, and hydrogen production rate in different scenarios. The results proved to be very accurate compared to the analytical results. Hyperparameter tuning was utilized to adjust the model parameters, and the models’ results showed an MAE lower than 1.98% and an R2 higher than 0.98.

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“…Although a few groups have focused on improving the airstream channel of the meltblown die, doing so would likely improve the meltblown airstream field and thereby lead to an ultrafine meltblown fiber. The Laval nozzle is a type of shrink-expansion nozzle invented by Gustav Patrik de Laval for steam engine applications and is now used in numerous situations. , Laval nozzles accelerate low-velocity airstreams to produce a high-velocity airstream and can even accelerate airstream from subsonic to supersonic speeds. Tan et al installed Laval nozzles under the traditional meltblown die and studied the characteristics of the meltblown airstream field with and without Laval nozzles.…”

Section: Introductionmentioning

confidence: 99%

Influence of a Meltblown Die with a Laval Airstream Channel on the Manufacturing Process of a Polymer Fiber Based on an Orthogonal Test and Simulation Analysis

Guo,

Zhu

2023

ACS Omega

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A Laval nozzle is a device that accelerates a low-speed airstream to form a high-speed airstream. In this work, we use a Laval nozzle in the airstream channel design of a meltblown die to improve the tensile properties of the fiber in the airstream field of the meltblown die. The features of the airstream field of the meltblown die are analyzed by numerical simulation. For a given parametrization, six factors may be tuned to optimize the performance of the Laval airstream channel of the meltblown die. We thus use a five-level, six-factor orthogonal test method to optimize the airstream channel of the meltblown die to determine the various factors that influence the airstream field beneath the meltblown die. The results show that the optimized Laval meltblown die performs better than the traditional die and that the widths of the larynx and expansion segment most strongly affect the airstream velocity beneath the Laval meltblown die. Compared with a traditional die, the Laval die optimized by orthogonal testing increases the peak airstream velocity by 17.54%, average velocity by 96.81%, average temperature by 12.32%, and peak pressure by 14.61% and produces weaker turbulence intensity near the spinneret. These characteristics make the airstream beneath the die more stable and uniform and accelerate the attenuation of the fiber diameter, producing more polymer nanofibers. These results demonstrate a valuable approach to the design and optimization of meltblown dies and provide a technical reference for the production and application of the meltblown fiber production equipment.

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Investigation of counter-rotating shock wave and wave direction control of hollow rotating detonation engine with Laval nozzle

Cited by 59 publications

References 55 publications

Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

Research on Cavitation Characteristics and Influencing Factors of Herringbone Gear Pump

Thermodynamics Investigation and Artificial Neural Network Prediction of Energy, Exergy, and Hydrogen Production from a Solar Thermochemical Plant Using a Polymer Membrane Electrolyzer

Influence of a Meltblown Die with a Laval Airstream Channel on the Manufacturing Process of a Polymer Fiber Based on an Orthogonal Test and Simulation Analysis

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