Three-Dimensional Flow Field in Rocket Pump Inducers—Part 1: Measured Flow Field Inside the Rotating Blade Passage and at the Exit

1973 ◽  
Vol 95 (4) ◽  
pp. 567-578 ◽  
Author(s):  
B. Lakshminarayana
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Layer Growth ◽  
Surface Boundary ◽  
Suction Surface ◽  
Flow Losses ◽  
Rotating Blade ◽  
Order Of Magnitude ◽  
Measured Flow ◽  
Boundary Layer Growth

The measurement of the flow field within the rotating passages as well as three-dimensional characteristics of the exit flow of an inducer model is reported in this paper. The flow within the inducer is probed by means of rotating pitot probe and pressure transfer device and at the exit by means of three hot wires located in three coordinate directions. In a high solidity inducer (4 bladed), considerable boundary layer growth is observed from hub to mid radius, while the flow from mid radius to tip is found to be highly complex, due to interaction of pressure and suction surface boundary layers and the resulting radial inward flow. The flow losses and wall shear stress derived from these measurements are found to be considerably higher than the corresponding stationary channel. The radial velocities are found to be of the same order of magnitude as axial velocities. Considerable improvement in the flow field is observed when the number of blades is decreased from four to three.

scholarly journals Three-Dimensional Boundary Layer on a Compressor Rotor Blade at Peak Pressure Rise Coefficient

1986 ◽  
Author(s):  
B. Lakshminarayana ◽  
P. Popovski
Keyword(s):  
Boundary Layer ◽  
Rotor Blade ◽  
Peak Pressure ◽  
Pressure Coefficient ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Layer Growth ◽  
Leakage Flow ◽  
Suction Surface ◽  
Compressor Rotor

A comprehensive study of the three-dimensional turbulent boundary layer on a compressor rotor blade at peak pressure rise coefficient is reported in this paper. The measurements were carried out at various chordwise and radial locations on a compressor rotor blade using a rotating miniature “V” configuration hot-wire probe. The data are compared with the measurement at the design condition. Substantial changes in the blade boundary layer characteristics are observed, especially in the outer sixteen percent of the blade span. The increased chordwise pressure gradient and the leakage flow at the peak pressure coefficient have a cumulative effect in increasing the boundary layer growth on the suction surface. The leakage flow has a beneficial effect on the pressure surface. The momentum and boundary layer thicknesses increase substantially from those at the design condition, especially near the outer radii of the suction surface.

Numerical study of the impact of water injection holes arrangement on cavitation flow control

2019 ◽  
Vol 103 (1) ◽  
pp. 003685041987774 ◽  
Author(s):  
Wei Wang ◽  
Qingdian Zhang ◽  
Tao Tang ◽  
Shengpeng Lu ◽  
Qi Yi ◽  
...  
Keyword(s):  
Flow Field ◽  
Numerical Study ◽  
Water Injection ◽  
Three Dimensional ◽  
Hydrodynamic Performance ◽  
Cavitation Flow ◽  
Suction Surface ◽  
Double Row ◽  
Suppression Effect ◽  
The Impact

A method of water injection to flow field using distributed holes on the suction surface of hydrofoil is presented in this article to control cavitation flow. Modified renormalization group k–ε turbulence model is coupled with full-cavitation model to calculate periodical cavitation patterns and the dynamic characteristics of the NACA66(MOD) hydrofoil. Water injection is found to be highly effective for cavitation suppression. The cavitation suppression effect of distributed regulation of jet holes and porosities along three-dimensional spanwise hydrofoil is also investigated. The appropriate porosities of single row spanwise jet holes and optimal jet position of double row jet holes are revealed for both cavitation suppression and good hydrodynamic performance. Double row jet holes setting in forward trapezoidal arrangement shows great potential for cavitation suppression and hydrodynamic performance. This research provides a method of water injection to flow field to actively control cavitation, which will facilitate development of engineering designs.

Comparison of Two Base-Potentials for a Slender-Body Method

2012 ◽  
Author(s):  
Mahmoud Alidadi ◽  
Sander Calisal
Keyword(s):  
Three Dimensional ◽  
Slender Body ◽  
Surface Boundary ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Wave Elevation ◽  
Surface Boundary Conditions ◽  
Perturbation Potential ◽  
Order Of Magnitude ◽  
Body Method

The effects of two base-potentials on the accuracy of a slender-body method are studied in this paper. In the formulation for this method which is developed for the slender ships, the velocity potential is decomposed into a base-potential and a perturbation potential. Then using an order of magnitude analysis, the three-dimensional flow problem is simplified into a series of two-dimensional problems for the perturbation potential. These two-dimensional problems are solved with the linearized free surface boundary conditions, using a mixed Eulerian-Lagrangian method. Finally for the two base-potentials, the numerical wave elevation along a Wigleyull are compared with the experimental results.

Measurements and Prediction of the Effects of Surface Roughness on Profile Losses and Deviation in a Turbine Cascade

1998 ◽  
Vol 120 (1) ◽  
pp. 20-27 ◽  
Author(s):  
R. J. Kind ◽  
P. J. Serjak ◽  
M. W. P. Abbott
Keyword(s):  
Surface Roughness ◽  
Three Dimensional ◽  
Leading Edge ◽  
Computational Method ◽  
Roughness Height ◽  
Surface Boundary ◽  
Turbine Cascade ◽  
Suction Surface ◽  
Roughness Effects ◽  
Profile Losses

Measurements of pressure distributions, profile losses, and flow deviation were carried out on a planar turbine cascade in incompressible flow to assess the effects of partial roughness coverage of the blade surfaces. Spanwise-oriented bands of roughness were placed at various locations on the suction and pressure surfaces of the blades. Roughness height, spacing between roughness elements, and band width were varied. A computational method based on the inviscid/viscous interaction approach was also developed; its predictions were in good agreement with the experimental results. This indicates that good predictions can be expected for a variety of cascade and roughness configurations from any two-dimensional analysis that couples an inviscid method with a suitable rough surface boundary-layer analysis. The work also suggests that incorporation of the rough wall skin-friction law into a three-dimensional Navier–Stokes code would enable good predictions of roughness effects in three-dimensional situations. Roughness was found to have little effect on static pressure distribution around the blades and on deviation angle, provided that it does not precipitate substantial flow separation. Roughness on the suction surface can cause large increases in profile losses; roughness height and location of the leading edge of the roughness band are particularly important. Loss increments due to pressure-surface roughness are much smaller than those due to similar roughness on the suction surface.

The boundary layer due to a three-dimensional vortex loop

1987 ◽  
Vol 185 ◽  
pp. 569-598 ◽  
Author(s):  
S. Ersoy ◽  
J. D. A. Walker
Keyword(s):  
Boundary Layer ◽  
Three Dimensional ◽  
Symmetry Plane ◽  
Layer Growth ◽  
Plane Wall ◽  
Vortex Loop ◽  
Loop Shape ◽  
Layer Flow ◽  
Boundary Layer Growth ◽  
Moving Vortex

The nature of the boundary layer induced by the motion of a three-dimensional vortex loop towards a plane wall is considered. Initially the vortex is taken to be a ring approaching a plane wall at an angle of attack in an otherwise stagnant fluid; the ring rapidly distorts into a loop shape due to the influence of the wall and the trajectory is computed from a numerical solution of the Biot-Savart integral. As the vortex loop moves, an unsteady boundary-layer flow develops on the wall. A method is described which allows the computation of the flow velocities on and near the symmetry plane of the vortex loop within the boundary layer. The computed results show the development of a variety of complex three-dimensional separation phenomena. Some of the solutions ultimately show strong localized boundary-layer growth and are suggestive that a boundary-layer eruption and a strong viscous-inviscid interaction will be induced by the moving vortex.

Measurement of 3D Flow Structure of Viscoelastic Fluid Using Digital Holographic Microscope

2015 ◽  
Author(s):  
Xiao-Bin Li ◽  
Masamichi Oishi ◽  
Tsukasa Matsuo ◽  
Marie Oshima ◽  
Feng-Chen Li ◽  
...  
Keyword(s):  
Flow Field ◽  
Real Time ◽  
Viscoelastic Fluid ◽  
Three Dimensional ◽  
Complex Flow ◽  
Micro Particle Image Velocimetry ◽  
Dimensional Measurement ◽  
Tracer Particles ◽  
Three Dimensional Measurement ◽  
Measured Flow

This paper aims to develop a three-dimensional measurement approach to investigate the flow structures of viscoelastic fluid in the curved microchannel by using digital holographic microscope (DHM). With the advantage of DHM, the real-time three-dimensional measurement for the complex flow field can be accomplished. The measurment system uses off-axis holographic / interferometric optical setup for the target, and 3D3C particle tracking velocimetry (PTV) can be achieved based on the analysis of phase information of holograms. To diagnose the chaotic flow inside the microchannel, the 3D temporal positions of tracer particles in the volume of 282μm × 282μm × 60μm have been detected and real-time velocity vectors were calculated based on the PTV algorithm. The measured flow field was then compared with the results obtained by using confocal micro particle image velocimetry (PIV). This technique is proven to be successful for the measurements of microfluidic flow, especially for the truly real-time 3D motions.

Three Components- and Tomographic-PIV Measurements of a Cyclone Cooling Flow in a Swirl Tube

2013 ◽  
Author(s):  
Christoph Biegger ◽  
Bernhard Weigand ◽  
Alice Cabitza
Keyword(s):  
Flow Field ◽  
Vortex Breakdown ◽  
Tracer Particle ◽  
Three Dimensional ◽  
Axial Flow ◽  
Leading Edge ◽  
Generic Model ◽  
Tube Axis ◽  
Tomographic Piv ◽  
Order Of Magnitude

Swirl cooling is a very efficient method for turbine blade cooling. However, the flow in such a system is quite complicated. In order to gain understanding of the flow structure, the velocity field in a leading edge swirl cooling chamber with two tangential inlet ducts is experimentally studied via Particle Image Velocimetry (PIV). The examined swirl tube is 1 m long and has a diameter of 50 mm. It represents an upscaled generic model of a leading edge swirl chamber. The Reynolds number, defined by the bulk velocity and the swirl tube diameter, ranges from 10,000 to 40,000, and the swirl number is 5.3. Velocity fields are measured in the center plane of the tube axis with stereo- and tomographic-PIV using two and four CCD cameras respectively. Tomographic-PIV is a three-dimensional PIV technique relying on the illumination, recording, reconstruction and cross correlation of a tracer particle distribution in a measurement volume opposed to a plane in stereo-PIV. For statistical analysis 2,000 vector maps are calculated and evaluations show a sample size of 1,000 ensembles is sufficient. Our experiment showed, that the flow field is characterized by a vortex system around the tube axis. Near the tube wall we observed an axial flow towards the outlet with a circumferential velocity component in the same order of magnitude. In contrast the vortex core consists of an axial backflow (vortex breakdown). The gained understanding of the flow field allows to predict regions of enhanced heat transfer in swirl chambers.

Unsteady Flow Behavior due to Breakdown of Tip Leakage Vortex in an Axial Compressor Rotor at Near-Stall Condition

2000 ◽  
Author(s):  
Masato Furukawa ◽  
Kazuhisa Saiki ◽  
Kazutoyo Yamada ◽  
Masahiro Inoue
Keyword(s):  
Unsteady Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Surface Boundary ◽  
Pressure Side ◽  
Suction Surface ◽  
Tip Leakage Vortex ◽  
Tip Leakage ◽  
Pressure Surface ◽  
Compressor Rotor

The unsteady flow nature caused by the breakdown of the tip leakage vortex in an axial compressor rotor at near-stall conditions has been investigated by unsteady three-dimensional Navier-Stokes flow simulations. The simulations show that the spiral-type breakdown of the tip leakage vortex occurs inside the rotor passage at the near-stall conditions. Downstream of the breakdown onset, the tip leakage vortex twists and turns violently with time, thus interacting with the pressure surface of the adjacent blade. The motion of the vortex and its interaction with the pressure surface are cyclic. The vortex breakdown causes significant changes in the nature of the tip leakage vortex, which result in the anomalous phenomena in the time-averaged flow fields near the tip at the near-stall conditions: no rolling-up of the leakage vortex downstream of the rotor, disappearance of the casing wall pressure trough corresponding to the leakage vortex, large spread of the low-energy fluid accumulating on the pressure side, and large pressure fluctuation on the pressure side. As the flow rate is decreased, the movement of the tip leakage vortex due to its breakdown becomes so large that the leakage vortex interacts with the suction surface as well as the pressure one. The interaction with the suction surface gives rise to the three-dimensional separation of the suction surface boundary layer.

scholarly journals A Quasi-Three Dimensional Analysis of Choking Flow for Radial Gas Turbines

1978 ◽  
Author(s):  
Yoshiyuki Nakase ◽  
Junichiro Fukutomi ◽  
Masanobu Inubushi ◽  
Takashi Watanabe ◽  
Yoshiyasu Hama ◽  
...  
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Energy Recovery ◽  
Three Dimensional ◽  
Layer Growth ◽  
Meridional Plane ◽  
Mixed Flow ◽  
Numerical Examples ◽  
Annular Cascade ◽  
Boundary Layer Growth

A quasi-three dimensional.flow analysis has previously been reported for a mixed flow impeller by one of the present authors. In the analysis, the velocity gradient method has been used in meridional plane and the rotating annular cascade theory has been used for blade-to-blade solution. In this report, the analysis is generalized to allow prediction and analysis of choking flow for a radial inflow gas turbine. Moreover, this analysis is corrected to include passage contraction effects and passage loss effects due to boundary-layer growth. The efficiency and choking flow rate of gas turbine may be obtained in a single computer run without the complicated throat area estimation. Some numerical examples for a burst furnace gas energy recovery turbine are presented.

Control of separations in a highly loaded diffusion cascade by tailored boundary layer suction

2013 ◽  
Vol 228 (8) ◽  
pp. 1363-1374 ◽  
Author(s):  
Zhiyuan Cao ◽  
Bo Liu ◽  
Ting Zhang
Keyword(s):  
Boundary Layer ◽  
Static Pressure ◽  
Three Dimensional ◽  
Flow Fields ◽  
Separated Flows ◽  
Surface Boundary ◽  
Suction Surface ◽  
Surface Boundary Layer ◽  
Boundary Layer Suction ◽  
Highly Loaded

In order to explore the control mechanism of boundary layer suction on the separated flows of highly loaded diffusion cascades, a linear compressor cascade, which has separated flows on the whole span and three-dimensional separations over the suction surface/endwall corner, was investigated by tailored boundary layer suction. Three suction surface-slotted schemes and two combined suction surface/endwall-slotted schemes were designed. The original cascade and the cascade with part blade span suction were experimentally investigated on a high-subsonic cascade wind tunnel. In addition, numerical simulation was employed to study the flow fields of different suction schemes in detail. The results shows that while tailored boundary layer suction at part blade span can effectively remove the separations at the suction span, the flow fields of other spans deteriorated. The reasons are the ‘C’ shape or reverse ‘C’ shape spanwise distribution of static pressure after part blade span boundary layer suction. Suction surface boundary layer suction over the whole span can obviously eliminate the separation at the suction surface. However, because of the endwall boundary layer, suction surface boundary layer suction cannot effectively remove the corner three-dimensional separation. The separation over the whole span and the three-dimensional separation at the corner are completely eliminated by combined suction surface/endwall boundary layer suction. After combined boundary layer suction, the static pressure distribution over the blade span just like the shape of ‘C’ is good for the transport of the low-energy fluid near the endwall to the midspan.

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