Flow Characterization of Supersonic Jets Issuing From Double-Beveled Nozzles

2018 ◽  
Vol 141 (1) ◽  
Author(s):  
Jie Wu ◽  
H. D. Lim ◽  
Xiaofeng Wei ◽  
T. H. New ◽  
Y. D. Cui
Keyword(s):  
Supersonic Jets ◽  
Navier Stokes ◽  
Shock Cell ◽  
Potential Core ◽  
Schlieren System ◽  
Flow Characterization ◽  
Mixing Behavior ◽  
Nozzle Pressure ◽  
Significant Mass

Supersonic jets at design Mach number of 1.45 issuing from circular 30 deg and 60 deg double-beveled nozzles have been investigated experimentally and numerically in the present study, with a view to potentially improve mixing behavior. Reynolds-averaged Navier–Stokes (RANS) simulations of the double-beveled nozzles and a benchmark nonbeveled nozzle were performed at nozzle-pressure-ratios (NPR) between 2.8 and 5.0, and the results are observed to agree well with Schlieren visualizations obtained from a modified Z-type Schlieren system. Double-beveled nozzles are observed to produce shorter potential core lengths, modifications to the first shock cell lengths that are sensitive toward the NPR and jet half-widths that are typically wider and narrower along the trough-to-trough (TT) and peak-to-peak (PP) planes, respectively. Lastly, using double-beveled nozzles leads to significant mass flux ratios at NPR of 5.0, with a larger bevel-angle demonstrating higher entrainment levels.

Flow Mixing and Screech Characteristics of Elliptical Supersonic Jet

2018 ◽  
Vol 0 (0) ◽  
Author(s):  
S. Manigandan ◽  
K. Vijayaraja
Keyword(s):  
Pressure Ratio ◽  
Expansion Ratio ◽  
Shock Cell ◽  
Nozzle Pressure Ratio ◽  
Potential Core ◽  
Appreciable Change ◽  
Jet Mixing ◽  
Screech Tone ◽  
Core Length ◽  
Nozzle Pressure

Abstract The acoustic and flow characteristics of a jet with elliptical throat is studied at different levels of nozzle expansion ratio. In this study, we have taken two types of CD nozzle configuration (circular and elliptical throat) and it is studied for various NPR ratios of 2, 3, 4 and 6. In addition, the acoustic characteristic of the jet flow is also measured for respective NPRs. Measurements of acoustic data are done using microphones placed at 30, 60 and 90 degrees to imprison the effects of screech tone. At NPR 2, 3 and 4, the jet with elliptical throat witnesses superior mixing and shorter core length compared to the circular throat. Its surprising to see both the configurations provides the identical oscillation at NPR 2, 3 and 4, however the efficiency of jet mixing is larger in elliptical throat jet. As the nozzle pressure ratio increased from 2 to 3 and 3 to 4, the potential core length of the jet reduces marginally about 5 to 10 % for every NPR until nozzle pressure ratio of 5. At NPR 2 and 3, the centerline pitot pressure profile shows, the decay of jet from the elliptical throat is healthier than a circular jet. At various levels of nozzle expansion, shock cell shows an appreciable change with an increase in NPR. Introduction of the elliptical throat on circular modifies the structure of shock cell which significantly changes the magnitude of screech tone due to the weakening of shock waves.

Noise and Flow Characterization of Supersonic Jets Emanating from a Circular and Faceted Nozzles

2020 ◽  
Author(s):  
Mohammad Saleem ◽  
Omar Lopez Rodriguez ◽  
Ephraim Gutmark ◽  
Junhui Liu ◽  
YuYu Khine
Keyword(s):  
Supersonic Jets ◽  
Flow Characterization

scholarly journals Extended lubrication theory: improved estimates of flow in channels with variable geometry

2017 ◽  
Vol 473 (2206) ◽  
pp. 20170234 ◽  
Author(s):  
Behrouz Tavakol ◽  
Guillaume Froehlicher ◽  
Douglas P. Holmes ◽  
Howard A. Stone
Keyword(s):  
Stokes Equations ◽  
Perturbation Expansion ◽  
Accurate Estimate ◽  
Higher Order ◽  
Lubrication Theory ◽  
Channel Height ◽  
Fluid Films ◽  
Flow Characterization ◽  
Systematic Perturbation

Lubrication theory is broadly applicable to the flow characterization of thin fluid films and the motion of particles near surfaces. We offer an extension to lubrication theory by starting with Stokes equations and considering higher-order terms in a systematic perturbation expansion to describe the fluid flow in a channel with features of a modest aspect ratio. Experimental results qualitatively confirm the higher-order analytical solutions, while numerical results are in very good agreement with the higher-order analytical results. We show that the extended lubrication theory is a robust tool for an accurate estimate of pressure drop in channels with shape changes on the order of the channel height, accounting for both smooth and sharp changes in geometry.

Linking Diagenesis, NMR, and Dynamic Data for Accurate Flow Characterization of Heterogeneous Carbonate Reservoir

2014 ◽  
Author(s):  
Umer Farooq ◽  
Reza Iskandar ◽  
El Sayed Moustafa Radwan ◽  
Magdy Ahmed H Hozayen
Keyword(s):  
Carbonate Reservoir ◽  
Dynamic Data ◽  
Flow Characterization

Computational Characterization of Passive Fluid Mixing in Microfluidics

Volume 3 ◽  
2004 ◽  
Author(s):  
Erik D. Svensson
Keyword(s):  
Stokes Equations ◽  
Initial Conditions ◽  
Three Dimensional ◽  
Fluid Mixing ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Fluid Systems ◽  
Sensitive Dependence ◽  
Microfluidic Mixers

In this work we computationally characterize fluid mixing in a number of passive microfluidic mixers. Generally, in order to systematically study and characterize mixing in realistic fluid systems we (1) compute the fluid flow in the systems by solving the stationary three-dimensional Navier-Stokes equations or Stokes equations with a finite element method, and (2) compute various measures indicating the degree of mixing based on concepts from dynamical systems theory, i.e., the sensitive dependence on initial conditions and mixing variance.

Characterization and screening of tight binding inhibitors of xanthine oxidase: an on-flow assay

RSC Advances ◽  
2015 ◽  
Vol 5 (47) ◽  
pp. 37533-37538 ◽  
Author(s):  
M. V. N. Rodrigues ◽  
R. S. Corrêa ◽  
K. L. Vanzolini ◽  
D. S. Santos ◽  
A. A. Batista ◽  
...  
Keyword(s):  
Xanthine Oxidase ◽  
Tight Binding ◽  
Flow Characterization ◽  
Binding Inhibitors

On-flow characterization of tight binders of xanthine oxidase.

Flow Characterization Of Miscible Displacement Processes

1997 ◽  
Author(s):  
S.R. Shadizadeh ◽  
F.G. Javadpour ◽  
R. Knox ◽  
D. Menzie
Keyword(s):  
Miscible Displacement ◽  
Flow Characterization ◽  
Displacement Processes

Rotordynamic characterization of tilting-pad bearings with eight pads in vertical rotors

2021 ◽  
pp. 1-20
Author(s):  
David J Rondon ◽  
Gudeta Berhanu Benti ◽  
Jan-Olov Aidanpää ◽  
Rolf Gustavsson
Keyword(s):  
Stokes Equations ◽  
Forced Response ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Mean Values ◽  
Stationary Coordinate System ◽  
Tilting Pad ◽  
Tilting Pad Bearings ◽  
Stiffness And Damping

Abstract It has been documented that stiffness and damping for a four-pad bearing are dependent not only the magnitude of the load but also on the position of the rotor in the bearing. However, 8-pad bearings are not commonly employed on horizontal turbines, and the presence of several pads in the bearing will decisively affect the dynamics of the system. This paper evaluates the stiffness and damping coefficients of tilting-pad bearings with eight pads and explore the main frequencies acting on the forced response of a vertical rotor. The bearing properties were modeled as a function of eccentricity and position in the stationary coordinate system by Navier-Stokes equations whose results are taken from commercial software. The simulated unbalanced response is compared to experimental results; the changing position of the shaft produces a periodic stiffness and damping, which is dependent on the number of pads. Cross-coupled coefficients influence is discussed, showing that their absence makes an accurate model for the mean values. The results indicate that simulation of vertical rotors with 8-pad bearings can be simplified which allow more effective simulations and dynamic analysis.

Sign in / Sign up

Export Citation Format

Share Document