scholarly journals Three-Dimensional Laser-Interferometric CT Measurement of High-Speed and Unsteady Flow Field Discharged from Open End

2006 ◽  
Vol 26 (Supplement1) ◽  
pp. 349-352
Author(s):  
Masanori Ota ◽  
Toshihiro Koga ◽  
Kazuo Maeno
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
High Speed ◽  
Three Dimensional ◽  
Laser Interferometric ◽  
Ct Measurement

scholarly journals Numerical and Experimental Study of Flow Field between the Main Hull and Demi-Hull of a Trimaran

2020 ◽  
Vol 8 (12) ◽  
pp. 975
Author(s):  
Cong Sun ◽  
Chunyu Guo ◽  
Chao Wang ◽  
Lianzhou Wang ◽  
Jianfeng Lin
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Light Transmission ◽  
Transmission Rate ◽  
Laser Sheet ◽  
Three Dimensional ◽  
Wake Flow ◽  
Navier Stokes ◽  
Unsteady Wake ◽  
Real Flow

The interactions between the main hull and demi-hull of trimarans have been arousing increasing attention, and detailed circumferential flow fields greatly influence trimaran research. In this research, the unsteady wake flow field of a trimaran was obtained by Reynolds-Averaged Navier-Stokes (RANS) equations on the basis of the viscous flow principles with consideration of the heaving and pitching of the trimaran. Then, we designed an experimental method based on particle-image velocimetry (PIV) and obtained a detailed flow field between the main hull and demi-hull of the trimaran. A trimaran model with one demi-hull made of polycarbonate material with 90% light transmission rate and a refractive index 1.58 (close to that of water 1.33) was manufactured as the experiment sample. Using polycarbonate material, the laser-sheet light-source transmission and high-speed camera recording problems were effectively rectified. Moreover, a nonstandard calibration was added into the PIV flow field measurement system. Then, we established an inverse three-dimensional (3D) distortion coordinate system and obtained the corresponding coordinates by using optics calculations. Further, the PIV system spatial mapping was corrected, and the real flow field was obtained. The simulation results were highly consistent with the experimental data, which showed the methods established in this study provided a strong reference for obtaining the detailed flow field information between the main hull and demi-hull of trimarans.

The effect analysis of an engine jet on an aircraft blast deflector

2018 ◽  
Vol 41 (4) ◽  
pp. 990-1001
Author(s):  
Song Ma ◽  
Jianguo Tan ◽  
Xiankai Li ◽  
Jiang Hao
Keyword(s):  
High Temperature ◽  
Flow Field ◽  
High Speed ◽  
Deflection Angle ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Aircraft Engine ◽  
Experimental Results ◽  
Exhaust Gases ◽  
The Impact

This paper establishes a novel mathematical model for computing the plume flow field of a carrier-based aircraft engine. Its objective is to study the impact of jet exhaust gases with high temperature, high speed and high pressure on the jet blast deflector. The working condition of the nozzle of a fully powered on engine is first determined. The flow field of the exhaust jet is then numerically simulated at different deflection angle using the three-dimensional Reynolds averaged Navier–Stokes equations and the standard [Formula: see text]-[Formula: see text] turbulence method. Moreover, infra-red temperature tests are further carried out to test the temperature field when the jet blast deflector is at the [Formula: see text] deflection angle. The comparison between the simulation results and the experimental results show that the proposed computation model can perfectly describe the system. There is only 8–10% variation between them. A good verification is achieved. Moreover, the experimental results show that the jet blast deflector plays an outstanding role in driving the high-temperature exhaust gases. It is found that [Formula: see text] may be the best deflection angle to protect the deck and the surrounding equipment effectively. These data results provide a valuable basis for the design and layout optimization of the jet blast deflector and deck.

Numerical Simulation of Three Dimensional Unsteady Flow of the Ruston Turbine in Stirred Tank

2014 ◽  
Vol 1008-1009 ◽  
pp. 906-909
Author(s):  
Xiao Bing Wang
Keyword(s):  
Flow Field ◽  
Unsteady Flow ◽  
Three Dimensional ◽  
Stirred Tank ◽  
Eddy Simulation ◽  
Cavitation Phenomenon ◽  
Large Size ◽  
Velocity Flow ◽  
Large Eddy ◽  
Turbine Installation

Unsteady flow of a single six-blade ruston turbine in stirred tank is numerically simulated by using the large eddy simulation. Then the effect of the turbine installation position on mixing flow field is studied. The result shows that with a relatively low paddle installation position, mixing effect at the bottom of tank is obvious, while which go against the materials at the top layer mixing. When the paddle is installed at the top of the stirred tank, liquid splash and a concave downward liquid surface are easily caused. Finally the cavitation phenomenon is generated. When the paddle is installed from 1/3H to 2/3H, there are a uniform flow field distribution and higher average velocity flow. Large size vortex structures at the top and the bottom of the paddle are obvious which is beneficial to mix the materials.

scholarly journals Wake Region Measurements of a Highly Three-Dimensional Nozzle Guide Vane Tested at DRA Pyestock Using Particle Image Velocimetry

1994 ◽  
Author(s):  
M. Funes-Gallanzi ◽  
P. J. Bryanston-Cross ◽  
K. S. Chana
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Guide Vane ◽  
Three Dimensional ◽  
Light Sheet ◽  
Test Facility ◽  
Velocity Mapping ◽  
Nozzle Guide Vane ◽  
Nozzle Guide ◽  
Annular Cascade

The quantitative whole field flow visualization technique of PIV has over the last few years been successfully demonstrated for transonic flow applications. A series of such measurements has been made at DRA Pyestock. Several of the development stages critical to a full engine application of the work have now been achieved using the Isentropic Light Piston Cascade (ILPC) test facility operating with high inlet turbulence levels: • A method of seeding the flow with 0.5μm diameter styrene particles has provided an even coverage of the flow field. • A method of projecting a 1 mm thick high power Nd/YAG laser light sheet within the turbine stator cascade. This has enabled a complete instantaneous intra-blade velocity mapping of the flow field to be visualized, by a specially developed diffraction-limited optics arrangement. • Software has been developed to automatically analyze the data. Due to the sparse nature of the data obtained, a spatial approach to the extraction of the velocity vector data was employed. • Finally, a comparison of the experimental results with those obtained from a three-dimensional viscous flow program of Dawes; using the Baldwin-Lomax model for eddy viscosity and assuming fully turbulent flow. The measurements provide an instantaneous quantitative whole field visualization of a high-speed unsteady region of flow in a highly three-dimensional nozzle guide vane; which has been successfully compared with a full viscous calculation. This work represents the first such measurements to be made in a full-size transonic annular cascade at engine representative conditions.

Time Accurate Euler Simulation of Interaction of Nozzle Wake and Secondary Flow With Rotor Blade in an Axial Turbine Stage Using Nonreflecting Boundary Conditions

1995 ◽  
Author(s):  
S. Fan ◽  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Boundary Conditions ◽  
Unsteady Flow ◽  
Secondary Flow ◽  
Rotor Blade ◽  
Three Dimensional ◽  
Computational Domain ◽  
Turbine Stage ◽  
Axial Turbine ◽  
Unsteady Pressure

The objective of this paper is to investigate the three dimensional unsteady flow interactions in a turbomachine stage. A three-dimensional time accurate Euler code has been developed using an explicit four-stage Runge-Kutta scheme. Three-dimensional unsteady non-reflecting boundary conditions are formulated at the inlet and at the outlet of the computational domain to remove the spurious numerical reflections. The three-dimensional code is first validated for 2-D and 3-D cascades with harmonic vortical inlet distortions. The effectiveness of non reflecting boundary conditions is demonstrated. The unsteady Euler solver is then used to simulate the propagation of nozzle wake and secondary flow through rotor and the resulting unsteady pressure field in an axial turbine stage. The three dimensional and time dependent propagation of nozzle wakes in the rotor blade row and the effects of nozzle secondary flow on the rotor unsteady surface pressure and passage flow field are studied. It was found that the unsteady flow field in the rotor is highly three-dimensional and the nozzle secondary flow has significant contribution to the unsteady pressure on the blade surfaces. Even though the steady flow at the midspan is nearly two-dimensional, the unsteady flow is 3-D and the unsteady pressure distribution can not by predicted by a 2-D analysis.

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