Analysis of flow-field characteristics and pressure gain in air-breathing rotating detonation combustor

2021 ◽  
Vol 33 (12) ◽  
pp. 126112
Author(s):  
Kevin Wu ◽  
Shu-jie Zhang ◽  
Da-wen She ◽  
Jian-ping Wang
Keyword(s):  
Flow Field ◽  
Air Breathing ◽  
Flow Field Characteristics ◽  
Rotating Detonation

scholarly journals Coupled Fluid–Solid Numerical Simulation for Flow Field Characteristics and Supporting Performance of Flexible Support Cylindrical Gas Film Seal

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  
Keyword(s):  
Flow Field ◽  
Film Thickness ◽  
Fluid Dynamic ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Flexible Support ◽  
Flow Field Characteristics

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.

scholarly journals Influence of Vortex Finder Structure on Separation Performance of Double-Overflow Three-Product Hydrocyclones

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 79
Author(s):  
Yuekan Zhang ◽  
Jiangbo Ge ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Junru Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Experimental Research ◽  
Separation Efficiency ◽  
Structural Parameters ◽  
Separation Performance ◽  
Insertion Depth ◽  
Flow Field Characteristics ◽  
Vortex Finder ◽  
Fine Classification

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.

scholarly journals Design of a Double-Nozzle Air Spray Gun and Numerical Research in the Interference Spray Flow Field

Coatings ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 475
Author(s):  
Yin-An Wang ◽  
Xiao-Peng Xie ◽  
Xiao-Hui Lu
Keyword(s):  
Flow Field ◽  
Central Region ◽  
Interference Effect ◽  
Thickness Distribution ◽  
Computational Domain ◽  
Coating Film ◽  
Discrete Phase Model ◽  
Spray Painting ◽  
Flow Field Characteristics ◽  
Spray Gun

Spray painting robots equipped with air spray guns have been widely used in the painting industry. In view of the low efficiency of single-nozzle air spray guns when spraying large targets, a new double-nozzle air spray gun structure was designed in this paper based on the Coanda effect of double jets. Firstly, a 3-D physical model of the double-nozzle air spray gun was built in Solidworks, in which unstructured grids were generated for the computational domain by ICEM. Secondly, the spray painting process was numerically modeled with the help of the computational fluid dynamics (CFD) software ANSYS-Fluent 16.0. The two-phase spray flow was calculated by coupling a discrete phase model (DPM) and the Taylor analogy breakup (TAB) method. The TAB model was applied to predict the secondary break-up. The DPM model was applied to predict the droplet trajectories. The geometry of an air spray gun has a significant influence on the spray flow field characteristics. The influence of the air spray gun geometry on the interference spray flow field characteristics and coating film thickness distribution were investigated by changing the values of the distance between the centers of the two paint holes (L) and the angle between the axes of the two paint holes (θ). Numerical results show that the smaller L and θ are, the stronger the interference effect between the two jets, while the more concentrated the paint is in the central region of the target surface, the easier it is for overspray to occur. With increasing L and θ, the interference effect gradually decreased and the extension distance of the coating film along the x-axis gradually increased. However, if L and θ are too large, the interference effect will become too weak and the shape of the coating film will become a concave, with more paint on both side regions and less paint in the central region, which will cause an uneven coating film. From the simulation results, it can be concluded that a more uniform coating film can be obtained when L = 30 mm and θ = 10°. The effective coating width of the double-nozzle air spray gun was increased by 85.7% compared with the single-nozzle air spray gun, which improved the spraying efficiency.

Effects of Flue Gas Inlet Structure on the Flow Field Characteristics of Multi-Stage Liquid Column Scrubber

2013 ◽  
Vol 773 ◽  
pp. 749-754
Author(s):  
Zhen Ya Duan ◽  
Fu Lin Zheng ◽  
Hui Ling Shi ◽  
Jun Mei Zhang
Keyword(s):  
Flow Field ◽  
Flue Gas ◽  
Static Pressure ◽  
Liquid Column ◽  
Liquid Distribution ◽  
Multi Stage ◽  
Flow Field Characteristics ◽  
Wall Flow ◽  
Two Peaks ◽  
Saddle Shape

In this paper, the numerical model of multi-stage liquid column scrubber was established. The flow field of liquid column scrubber with different inlet structure was respectively simulated by a commercial CFD code, Fluent. Considering the distribution characteristics of static pressure and velocity in the scrubber, this inlet type, single horizontal gas inlet with a notch at the bottom, is regarded as the most reasonable structure. On one hand, that structure has uniform distribution of static pressure. On the other hand, the velocity profile of its field presents saddle shape, i.e. the low central velocity exists between two peaks, which could contribute to weakening wall-flow phenomenon and obtaining uniform gas-liquid distribution.

A Study of Two-Dimensional Supersonic Air Ejector Systems

1973 ◽  
Vol 187 (1) ◽  
pp. 733-743
Author(s):  
R. S. Benson ◽  
V. A. Eustace
Keyword(s):  
Flow Field ◽  
Secondary Flow ◽  
Ambient Pressure ◽  
Performance Characteristics ◽  
Constant Density ◽  
Two Dimensional ◽  
Theoretical Predictions ◽  
Flow Field Characteristics ◽  
Air Ejector

The performance and flow field characteristics for two-dimensional ejector systems are determined theoretically for the condition when operation is independent of ambient pressure. The method considers the detailed inviscid interaction between the primary and secondary streams within the mixing tube and an estimate is made of the secondary flow entrained by the two-stream viscous mixing region. The validity of the theory is tested by comparing the performance characteristics of an experimental ejector facility with theoretical predictions and by comparing the theoretical flow field, in terms of constant density contours, with infinite fringe interferograms.

An Experimental Investigation of the Effects of the Environmental Conditions and the Channel Depth for an Air-Breathing Polymer Electrolyte Membrane Fuel Cell

2008 ◽  
Vol 5 (4) ◽  
Author(s):  
Yong Hun Park ◽  
Jerald A. Caton
Keyword(s):  
Fuel Cell ◽  
Relative Humidity ◽  
Flow Field ◽  
Current Density ◽  
Environmental Conditions ◽  
Polymer Electrolyte Membrane ◽  
Channel Depth ◽  
Air Breathing ◽  
Fuel Cell Performance ◽  
Electrolyte Membrane

The effects of the environmental conditions and the channel depth for an air-breathing polymer electrolyte membrane fuel cell were investigated experimentally. The fuel cell used in this work included a membrane and electrode assembly, which possessed an active area of 25 cm2 with Nafion® 117 membrane. Triple serpentine designs for the flow fields with two different flow depths were used in this research. The experimental results indicated that the relative humidity and temperature play an important role with respect to fuel cell performance. The fuel cell needs to be operated at least 20 min to obtain stable performance. When the shallow flow field was used, the performance increased dramatically for low humidity and slightly for high humidity. The current density was obtained around only 120 mA/cm2 at 30°C with an 80% relative humidity, which was nearly double the performance for the deep flow field. The minimum operating temperature for an air-breathing fuel cell would be 20°C. When it was 10°C at 60% relative humidity, the open circuit voltage dropped to around 0.65 V. The fuel cell performance improved with increasing relative humidity from 80% to 100% at high current density.

Flow Field Characteristics of Oblique Shocks Generated Using Microjet Arrays

2014 ◽  
Vol 6 (3) ◽  
pp. 93-110 ◽  
Author(s):  
Mohd Ali ◽  
Farrukh Alvi ◽  
Rajan Kumar ◽  
Kareem Ahmed
Keyword(s):  
Flow Field ◽  
Flow Field Characteristics ◽  
Oblique Shocks
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