Surface Static Pressures in an Inlet Vortex Flow Field

1985 ◽  
Vol 107 (2) ◽  
pp. 387-393 ◽  
Author(s):  
W. Liu ◽  
E. M. Greitzer ◽  
C. S. Tan
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Velocity Ratio ◽  
Ground Plane ◽  
Vortex Formation ◽  
Three Dimensional ◽  
Static Pressure Distribution ◽  
Pressure Distributions ◽  
Parametric Data ◽  
Basic Ideas

An experimental investigation of the three-dimensional flow field associated with an inlet vortex is reported. The specific configuration investigated is an inlet, in proximity to a ground plane, in crosswind. Parametric data are presented to define the regimes of vortex formation in this configuration, as a function of inlet height to diameter ratio and inlet velocity ratio. The detailed static pressure distribution on the inlet is given for two quite different flow regimes, one with a strong inlet vortex and one with no inlet vortex. These new quantitative data are supplemented by flow visualization studies that allow an estimate to be made of the circulation around the inlet vortex. It is argued that the static pressure distributions in both cases can be clearly interpreted using the basic ideas of inlet vortex formation that were previously developed from (qualitative) water tunnel studies.

Study of Flow Field in Compact Spinning with Pneumatic Groove

2011 ◽  
Vol 332-334 ◽  
pp. 260-263
Author(s):  
Shi Rui Liu
Keyword(s):  
Flow Field ◽  
Negative Pressure ◽  
Static Pressure ◽  
Three Dimensional ◽  
Three Dimensional Flow ◽  
Dimensional Flow ◽  
Compact Zone ◽  
Air Flows ◽  
Compact Spinning

In the paper the structure of the compact spinning with pneumatic groove is introduced and the characteristics of three-dimensional flow field of the compact spinning with pneumatic groove are also investigated. Results from this research confirmed that In the compact zone, the air flows to the groove and enters the inner hollow of the slot-roller through the round holes, and the air on both sides of the groove condenses to the center of it and flows to the round holes; It is beneficial to compact the fiber and make the fiber slip to the bottom of the groove with shrink shape; the velocity and negative pressure are both not homogeneous, as the round holes are not continual, and the gradient of static pressure and velocity in compact zones are also perceptible.

Three-dimensional flow in cavities

1963 ◽  
Vol 16 (4) ◽  
pp. 620-632 ◽  
Author(s):  
D. J. Maull ◽  
L. F. East
Keyword(s):  
Static Pressure ◽  
Three Dimensional ◽  
Two Dimensional ◽  
Three Dimensional Flow ◽  
Large Span ◽  
Dimensional Flow ◽  
Pressure Distributions ◽  
Oil Flow ◽  
Two Dimensional Flow

The flow inside rectangular and other cavities in a wall has been investigated at low subsonic velocities using oil flow and surface static-pressure distributions. Evidence has been found of regular three-dimensional flows in cavities with large span-to-chord ratios which would normally be considered to have two-dimensional flow near their centre-lines. The dependence of the steadiness of the flow upon the cavity's span as well as its chord and depth has also been observed.

Ingestion Into the Upstream Wheelspace of an Axial Turbine Stage

1994 ◽  
Vol 116 (2) ◽  
pp. 327-332 ◽  
Author(s):  
T. Green ◽  
A. B. Turner
Keyword(s):  
Pressure Distribution ◽  
Static Pressure ◽  
Three Dimensional ◽  
Computer Code ◽  
Rotor Blades ◽  
Rotor Speed ◽  
Turbine Stage ◽  
Flow Rates ◽  
Static Pressure Distribution ◽  
Axial Clearance

The upstream wheelspace of an axial air turbine stage complete with nozzle guide vanes (NGVs) and rotor blades (430 mm mean diameter) has been tested with the objective of examining the combined effect of NGVs and rotor blades on the level of mainstream ingestion for different seal flow rates. A simple axial clearance seal was used with the rotor spun up to 6650 rpm by drawing air through it from atmospheric pressure with a large centrifugal compressor. The effect of rotational speed was examined for several constant mainstream flow rates by controlling the rotor speed with an air brake. The circumferential variation in hub static pressure was measured at the trailing edge of the NGVs upstream of the seal gap and was found to affect ingestion significantly. The hub static pressure distribution on the rotor blade leading edges was rotor speed dependent and could not be measured in the experiments. The Denton three-dimensional C.F.D. computer code was used to predict the smoothed time-dependent pressure field for the rotor together with the pressure distribution downstream of the NGVs. The level and distribution of mainstream ingestion, and thus the seal effectiveness, was determined from nitrous oxide gas concentration measurements and related to static pressure measurements made throughout the wheelspace. With the axial clearance rim seal close to the rotor the presence of the blades had a complex effect. Rotor blades in connection with NGVs were found to reduce mainstream ingestion seal flow rates significantly, but a small level of ingestion existed even for very high levels of seal flow rate.

Effects of Stator Wakes and Spanwise Nonuniform Inlet Conditions on the Rotor Flow of an Axial Turbine Stage

1993 ◽  
Vol 115 (1) ◽  
pp. 128-136 ◽  
Author(s):  
J. Zeschky ◽  
H. E. Gallus
Keyword(s):  
Flow Field ◽  
Three Dimensional ◽  
Axial Flow ◽  
Tip Clearance ◽  
Hot Wire ◽  
Turbine Stage ◽  
Static Pressure Distribution ◽  
Inlet Conditions ◽  
Experimental Values ◽  
Rotor Flow

Detailed measurements have been performed in a subsonic, axial-flow turbine stage to investigate the structure of the secondary flow field and the loss generation. The data include the static pressure distribution on the rotor blade passage surfaces and radial-circumferential measurements of the rotor exit flow field using three-dimensional hot-wire and pneumatic probes. The flow field at the rotor outlet is derived from unsteady hot-wire measurements with high temporal and spatial resolution. The paper presents the formation of the tip clearance vortex and the passage vortices, which are strongly influenced by the spanwise nonuniform stator outlet flow. Taking the experimental values for the unsteady flow velocities and turbulence properties, the effect of the periodic stator wakes on the rotor flow is discussed.

Numerical and Experimental Investigation of Return Channel Vane Aerodynamics With Two-Dimensional and Three-Dimensional Vanes

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
A. Hildebrandt ◽  
F. Schilling
Keyword(s):  
Experimental Investigation ◽  
Flow Field ◽  
Static Pressure ◽  
Three Dimensional ◽  
Pressure Rise ◽  
Field Performance ◽  
Two Dimensional ◽  
Flow Angle ◽  
Overall Performance ◽  
Return Channel

The present paper deals with the numerical and experimental investigation of the effect of return channel (RCH) dimensions of a centrifugal compressor stage on the aerodynamic performance. Three different return channel stages were investigated, two stages comprising three-dimensional (3D) return channel blades and one stage comprising two-dimensional (2D) RCH vanes. The analysis was performed regarding both the investigation of overall performance (stage efficiency, RCH total pressure loss coefficient) and detailed flow-field performance. For detailed experimental flow-field investigation at the stage exit, six circumferentially traversed three-hole probes were positioned downstream the return channel exit in order to get two-dimensional flow-field information. Additionally, static pressure wall measurements were taken at the hub and shroud pressure and suction side (SS) of the 2D and 3D return channel blades. The return channel system overall performance was calculated by measurements of the circumferentially averaged 1D flow field downstream the diffuser exit and downstream the stage exit. Dependent on the type of return channel blade, the numerical and experimental results show a significant effect on the flow field overall and detail performance. In general, satisfactory agreement between computational fluid dynamics (CFD)-prediction and test-rig measurements was achieved regarding overall and flow-field performance. In comparison with the measurements, the CFD-calculated stage performance (efficiency and pressure rise coefficient) of all the 3D-RCH stages was slightly overpredicted. Very good agreement between CFD and measurement results was found for the static pressure distribution on the RCH wall surfaces while small CFD-deviations occur in the measured flow angle at the stage exit, dependent on the turbulence model selected.

EXPERIMENTAL AND NUMERICAL INVESTIGATION OF HYPERSONIC JAWS INLET

2010 ◽  
Vol 24 (13) ◽  
pp. 1409-1412 ◽  
Author(s):  
HAO DONG ◽  
CHENG-PENG WANG ◽  
KE-MING CHENG
Keyword(s):  
Boundary Layer ◽  
Flow Field ◽  
Static Pressure ◽  
Free Stream ◽  
Flow Coefficient ◽  
Plane Symmetric ◽  
Pressure Distributions ◽  
Planar Shock ◽  
Flow Field Characteristics ◽  
Planar Shock Wave

In order to obtain the flow field characteristics and the influence of boundary layer, numerical simulations and wind tunnel tests are conducted for two streamline traced Jaws inlets at Mach number 7. The inlets are designed based on a flow field with 8-7 planar shock wave (the ramp in pitch plane is inclined at 8° to the free stream and in yaw plane is inclined at 7° to the free stream, yielding planar shocks). In the study, the static pressure distributions were measured and analyzed along the plane-symmetric centerline of the inlet with and without the boundary layer correction, respectively. Results show that boundary layer correction can obviously weaken the viscous influence to the inlet, increasing the mass flow coefficient and improving total pressure recovery.

Investigation of the Flow Field on a Transonic Turbine Nozzle Guide Vane With Rim Seal Cavity Flow Ejection

2009 ◽  
Author(s):  
M. Pau ◽  
G. Paniagua
Keyword(s):  
Flow Field ◽  
Static Pressure ◽  
Numerical Study ◽  
Guide Vane ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Cavity Flow ◽  
Trailing Edge ◽  
Dynamic Simulations ◽  
Purge Flow

Ensuring an adequate life of high pressure turbines requires efficient cooling methods, such as rim seal flow ejection from the stator-rotor wheel space cavity interface, which prevents hot gas ingress into the rotor disk. The present work addresses the potential to improve the efficiency in transonic turbines at certain rim seal ejection rates. To understand this process a numerical study was carried out combining computational fluid dynamic simulations (CFD) and experiments on a single stage axial test turbine. The three dimensional steady CFD analysis was performed modeling the purge cavity flow ejected downstream of the stator blade row, at three flow regimes, subsonic M2 = 0.73, transonic M2 = 1.12 and supersonic M2 = 1.33. Experimental static pressure measurements were used to calibrate the computational model. The main flow field-purge flow interaction is found to be governed by the vane shock structures at the stator hub. The interaction between the vane shocks at the hub and the purge flow has been studied and quantitatively characterized as function of the purge ejection rate. The ejection of 1% of the core flow from the rim seal cavity leads to an increase of the hub static pressure of approximately 7% at the vane trailing edge. This local reduction of the stator exit Mach number decreases the trailing edge losses in the transonic regime. Finally, a numerically predicted loss breakdown is presented, focusing on the relative importance of the trailing edge losses, boundary layer losses, shock losses and mixing losses, as a function of the purge rate ejected. Contrary to the experience in subsonic turbines, results in a transonic model demonstrate that ejecting purge flow improves the vane efficiency due to the shock structures modification downstream of the stator.

Time-Averaged and Time-Accurate Aerodynamic Effects of Rotor Purge Flow for a Modern, One and One-Half Stage High-Pressure Turbine—Part II: Analytical Flow Field Analysis

2013 ◽  
Vol 136 (1) ◽  
Author(s):  
Brian R. Green ◽  
Randall M. Mathison ◽  
Michael G. Dunn
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Film Cooling ◽  
Gas Flow ◽  
Static Pressure ◽  
Pressure Ratio ◽  
Three Dimensional ◽  
Field Analysis ◽  
High Pressure Turbine ◽  
Purge Flow

The detailed mechanisms of purge flow interaction with the hot-gas flow path were investigated using both unsteady computationally fluid dynamics (CFD) and measurements for a turbine operating at design corrected conditions. This turbine consisted of a single-stage high-pressure turbine and the downstream, low-pressure turbine nozzle row with an aerodynamic design equivalent to actual engine hardware and typical of a commercial, high-pressure ratio, transonic turbine. The high-pressure vane airfoils and inner and outer end walls incorporated state-of-the-art film cooling, and purge flow was introduced into the cavity located between the high-pressure vane and disk. The flow field above and below the blade angel wing was characterized by both temperature and pressure measurements. Predictions of the time-dependent flow field were obtained using a three-dimensional, Reynolds-averaged Navier–Stokes CFD code and a computational model incorporating the three blade rows and the purge flow cavity. The predictions were performed to evaluate the accuracy obtained by a design style application of the code, and no adjustment of boundary conditions was made to better match the experimental data. Part I of this paper compared the predictions to the measurements in and around the purge flow cavity and demonstrated good correlation. Part II of this paper concentrates on the analytical results, looking at the primary gas path ingestion mechanism into the cavity as well as the effects of the rotor purge on the upstream vane and downstream rotor aerodynamics and thermodynamics. Ingestion into the cavity is driven by high static pressure regions downstream of the vane, high-velocity flow coming off the pressure side of the vane, and the blade bow waves. The introduction of the purge flow is seen to have an effect on the static pressure of the vane trailing edge in the lower 5% of span. In addition, the purge flow is weak enough that upon exiting the cavity, it is swept into the mainstream flow and provides no additional cooling benefits on the platform of the rotating blade.

3-D Numerical Simulation on Unsteady Turbulent Flow of Rotational Flow Self-Priming Pump

2012 ◽  
Vol 562-564 ◽  
pp. 899-902 ◽  
Author(s):  
Chun Lin Wang ◽  
Tian Fang Zhang ◽  
Chun Lei Zhao ◽  
Dong Liu
Keyword(s):  
Turbulent Flow ◽  
Static Pressure ◽  
Three Dimensional ◽  
Rotational Flow ◽  
Coupled Models ◽  
Simple Arithmetic ◽  
Sliding Mesh ◽  
Static Pressure Distribution ◽  
Mesh Model ◽  
Interior Flow

The three-dimensional unsteady turbulent flow of rotational flow self-priming pump was simulated by using Reynolds time-averaged N-S equations and the standard k-ε turbulent model, sliding mesh model of static-dynamic coupled models and SIMPLE arithmetic. The static pressure distribution of the pump central rotative surface and relative velocity of the impeller central rotative surface in a complete application cycle were analyzed. The rule of instantaneous head in a impeller channel cycle was studied, and the positions of maximal head and minimal head were analyzed. It revealed that the unsteady method can truly simulate the changes of the rotational flow self-priming pump interior flow, and the unsteady characteristic of interior flow in rotational flow self-priming pump is obvious and it changes as the relative position of impeller and volute change. The change is periodical, and its frequency is relate to the impeller number and the rotate speed of the pump.

Laminar Fluid Flow around Two Wall-Mounted Cubes of Arbitrary Configuration

2010 ◽  
Vol 224 (11) ◽  
pp. 2396-2407 ◽  
Author(s):  
M Eslami ◽  
M M Tavakol ◽  
E Goshtasbirad
Keyword(s):  
Fluid Flow ◽  
Flow Field ◽  
Free Stream ◽  
Three Dimensional ◽  
Bluff Bodies ◽  
Vortical Structures ◽  
Laminar Fluid Flow ◽  
Pressure Distributions ◽  
Arbitrary Configuration ◽  
Computational Fluid Dynamics Cfd

The problem of flow field around multiple bluff bodies mounted on a surface is of great significance in different fields of engineering. In this study, a computational fluid dynamics (CFD) code is developed to calculate three-dimensional (3D) steady state laminar fluid flow around two cuboids of arbitrary size and configuration mounted on a surface in free stream conditions. This study presents the results for two cubes of the same size mounted on a surface in both inline and staggered arrangements. Streamlines are plotted for various combinations of the distance between the two cubes and Reynolds number. Moreover, the effects of different parameters on vortical structures, separation, and reattachment points are discussed. Also, velocity and pressure distributions are plotted in the wake region behind the two cubes. It is clearly shown that how the presence of the second cube changes the flow field and the vortical structures in comparison with the case of a single cube.

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