An Aerodynamic Method for Control and Range Improvement of Rotary Compressors

1980 ◽  
Author(s):  
N. Kyrtatos ◽  
N. Watson
Keyword(s):  
Cross Flow ◽  
Inlet Pipe ◽  
Axisymmetric Jet ◽  
Inlet Guide Vanes ◽  
Aerodynamic Method ◽  
Compressor Inlet ◽  
Flow Situation ◽  
Combined Action ◽  
Jet Velocities ◽  
Good Agreement

An aerodynamic method is proposed to replace the variable inlet guide vanes used for imparting compressor inlet prewhirl. High pressure jets are injected obliquely into the inflow, from orifices spaced around the periphery of the inlet pipe. A mathematical model of the flow situation was developed, which considers an unbounded axisymmetric jet ejected obliquely at various angles into a cross flow. The solution for the trajectory and growth of the jet was found to be in good agreement with relevant published experimental data. Prewhirl producing jet arrangements were designed and the flow deflection resulting from the combined action of the jets was measured for a range of jet velocities and cross flow velocities.

Investigation of Circular and Shaped Effusion Cooling Arrays for Combustor Liner Application—Part 2: Numerical Analysis

2009 ◽  
Author(s):  
A. Andreini ◽  
C. Bianchini ◽  
A. Ceccherini ◽  
B. Facchini ◽  
L. Mangani ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Cross Flow ◽  
Lateral Spreading ◽  
Elliptical Cross ◽  
Injection Angle ◽  
Blowing Ratio ◽  
Combustor Liner ◽  
Effectiveness Data ◽  
Overall Effectiveness ◽  
Good Agreement

A numerical analysis of two different effusion cooled plates, with a feasible arrangement for combustor liner application, is presented in this paper. Though having the same porosity and very shallow injection angle (17°), the first configuration presents a “conventional” circular drilling, while the other has “shaped” holes with such an elliptical cross-section that leads to a circular imprint on the cooled surface. Either geometries were the object of an experimental survey in which both adiabatic and overall effectiveness were measured. In order to compensate for the lack of detailed aerodynamic measurements, 3D CFD computations were performed for the two geometries. Steady state RANS calculations were carried out using a k–ε Two Layer turbulence model, both in the standard isotropic and in an algebraically corrected non isotropic version specifically tuned to better predict the lateral spreading of jets in a cross flow. Flow characteristic reproduce typical effusion cooled combustor liner conditions with blowing ratio of 5 and coolant jet Reynolds number of 12500. Even though good agreement could not be obtained comparing thermal adiabatic effectiveness with experiments, the findings of the experiments regarding the rating of the cooling efficiency of the two configurations were confirmed. Additionally, conjugate simulations were performed for the circular hole geometry in order to quantify heat transfer effects and to directly compare them with raw experimental overall effectiveness data.

scholarly journals The Effects of Incident Turbulence and Moving Wakes on Laminar Heat Transfer in Gas Turbines

1992 ◽  
Author(s):  
K. Dullenkopf ◽  
R. E. Mayle
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Gas Turbines ◽  
Free Stream ◽  
Cross Flow ◽  
Turbulence Parameter ◽  
Constant Acceleration ◽  
Free Stream Turbulence ◽  
Laminar Boundary Layers ◽  
Good Agreement

The effect of free-stream turbulence and moving wakes on augmenting heat transfer in accelerating laminar boundary layers is considered. First, the the effect of free-stream turbulence is re-examined in terms of a Nusselt number and turbulence parameter which correctly account for the free-stream acceleration and a correlation for both cylinders in cross flow and airfoils with regions of constant acceleration is obtained. This correlation is then used in a simple quasi-steady model to predict the effect of periodically passing wakes on airfoil laminar heat transfer. A comparison of the predictions with measurements shows good agreement.

Wall Boundary Layers in Turbomachines

1972 ◽  
Vol 14 (6) ◽  
pp. 411-423 ◽  
Author(s):  
H. Marsh ◽  
J. H. Horlock
Keyword(s):  
Boundary Layer ◽  
Integral Equations ◽  
Cross Flow ◽  
Inlet Guide Vanes ◽  
Wall Boundary Layer ◽  
Wall Boundary ◽  
Alternative Approach ◽  
Flow Through ◽  
The Many ◽  
Momentum Integral

Equations for the passage-averaged flow in a cascade are used to derive the momentum integral equations governing the development of the wall boundary layer in turbomachines. Several existing methods of analysis are discussed and an alternative approach is given which is based on the passage-averaged momentum integral equations. The analysis leads to an anomaly in the prediction of the cross flow and to avoid this it is suggested that for the many-bladed cascade there should be a variation of the blade force through the boundary layer. This variation of the blade force can be included in the analysis as a force deficit integral. The growth of the wall boundary layer has been calculated by four methods and the predictions are compared with two sets of published experimental results for flow through inlet guide vanes.

scholarly journals Development of Inlet for an Axial Compressor

1968 ◽  
Author(s):  
R. C. Reisweber
Keyword(s):  
Axial Compressor ◽  
Axial Flow ◽  
Test Program ◽  
Guide Vanes ◽  
Inlet Guide Vanes ◽  
Compressor Inlet ◽  
Three Stages ◽  
Overall Performance

In development of an axial-flow boiler supercharger, a test program on the compressor inlet was carried out. Tests were run using a test compressor aerodynamically identical to the first three stages of the supercharger compressor. Prototype compressor inlet was compared to an axial inlet, and also to several modified inlets. While the prototype inlet showed considerably more distortion ahead of the inlet guide vanes than the axial inlet, the inlet guide vanes removed most of the distortion. As a result, overall performance of all inlet configurations was essentially the same.

An Additively Manufactured Four Sensor Fast Response Aerodynamic Probe

2020 ◽  
Author(s):  
Alexandros Chasoglou ◽  
Panagiotis Tsirikoglou ◽  
Anestis Kalfas ◽  
Reza Abhari
Keyword(s):  
First Generation ◽  
Incidence Angle ◽  
Three Dimensional ◽  
Fast Response ◽  
Design Development ◽  
Free Jets ◽  
Axisymmetric Jet ◽  
First Results ◽  
Binder Jetting ◽  
Good Agreement

Abstract The current work describes the design, development and testing of a miniature fast response aerodynamic probe (FRAP) with 4 sensors (4S), able to perform measurements in unsteady three-dimensional flow field. Moreover, the calibration and first results with the newly developed probe is also provided. The miniature FRAP-4S demonstrates a 3 mm tip diameter, which represents a 25% reduction in diameter size, in comparison to a first generation FRAP-4S, without any loss in terms of measurement bandwidth. The 3 mm outer casing of the probe is additively manufactured with a high-precision binder jetting technique. In terms of aerodynamic performance, the probe demonstrates high angular sensitivity up to at least ± 18° incidence angle in both directions. To evaluate the measurement accuracy of the newly developed FRAP-4S, measurements are performed at the Laboratory for Energy Conversion (LEC) in both a round axisymmetric jet and an one-and-a-half stage, unshrouded and highly-loaded axial turbine configuration. Turbulence measurements performed with the miniature FRAP-4S are compared against hot-wire studies in round free-jets found in the literature. Good agreement in both trends but also absolute values is demonstrated. Moreover, the performance of the probe is compared against traditional instrumentation developed at LEC, namely miniature pneumatic and FRAP-2S probes. The results indicate that the FRAP-4S, despite its larger size in comparison to the other probes tested, can resolve the main flow patterns, while the highest deviations occur in the presence of highly skewed and sheared flows. Furthermore, the additively manufactured probe was proven to be robust after more than 50 hours of testing in representative turbine environment configuration. Finally, it should be highlighted that the newly developed FRAP reduces measurement time by a factor of three in comparison to FRAP-2S, which directly translates to reduced development time and thus cost, during turbomachinery development phase.

Post-Buckling Analysis of Heavy Columns with Application to Marine Risers

1985 ◽  
Vol 29 (03) ◽  
pp. 162-169
Author(s):  
Theodore Kokkinis ◽  
Michael M. Bernitsas
Keyword(s):  
Boundary Conditions ◽  
Small Strain ◽  
Equilibrium Path ◽  
Drilling Mud ◽  
Tubular Columns ◽  
Buckling Behavior ◽  
Post Buckling ◽  
Combined Action ◽  
Raphson Iteration ◽  
Good Agreement

The post-buckling behavior of heavy tubular columns following static instability under the combined action of weight, tension/compression at the top, and fluid static pressure forces in the gravity field is studied. A two-dimensional nonlinear small-strain large-deflection model of the column is derived, consisting of an integrodifferential equilibrium equation and two end rotation conditions. The equation of equilibrium is discretized using a finite-element method. An approximate solution valid in the neighborhood of the bifurcation point and an incremental solution are used to determine the secondary equilibrium path. The results of both methods are corrected by Newton-Raphson iteration. Conditions for unstable initial post-buckling behavior and existence of limit points on the secondary equilibrium path are presented. The numerical solution is applied to the problem of the elastica and is found to be in good agreement with the analytical solution. The secondary equilibrium path for a 500-m-long (1640 ft) marine drilling riser is calculated for two sets of boundary conditions and various values of the drilling mud density. The effect of the drilling mud density and the boundary conditions on the riser's post-buckling behavior is discussed.

Strength and Deformation of Combined Beams with Side Reinforced Plates

2019 ◽  
Vol 968 ◽  
pp. 234-239
Author(s):  
Talyat Azizov ◽  
Oleksii Melnik ◽  
Oleksandr Myza
Keyword(s):  
Experimental Data ◽  
Reinforced Concrete ◽  
Experimental Studies ◽  
Calculated Data ◽  
Concrete Plate ◽  
Combined Action ◽  
Strength And Deformation ◽  
Concrete Plates ◽  
Good Agreement

The results of experimental studies of combined beams consisting of a stone part, reinforced with side reinforced concrete plates are given. Experimentally shown the viability of the proposed structures. The conditions for ensuring the combined action of a stone beam and a reinforced concrete plate are given. Cases are shown when one-sided plates can be used and when double-sided reinforced concrete plates can be used. A comparison of experimental data with the data calculated by the authors developed methods is given. A good agreement between theoretical and calculated data is shown.

Control of light gas releases in ventilated tunnels

2019 ◽  
Vol 872 ◽  
pp. 515-531 ◽  
Author(s):  
L. Jiang ◽  
M. Creyssels ◽  
G. R. Hunt ◽  
P. Salizzoni
Keyword(s):  
Richardson Number ◽  
Cross Flow ◽  
Smooth Transition ◽  
Ventilation Strategy ◽  
Simplified Models ◽  
Formula One ◽  
Source Radius ◽  
Reduced Scale ◽  
Specific Health ◽  
Good Agreement

The release of buoyant harmful gases within enclosed spaces, such as tunnels and corridors, may engender specific health, industrial and transportation risks. For safety, a simple ventilation strategy for these spaces is to impose a flow along the tunnel, whose velocity is defined as ‘critical’, that confines the front of harmful buoyant gases immediately downstream of the source of emission. Determining the critical velocity as a function of the geometrical and dynamical conditions at the source is a fundamental fluid mechanics problem which has yet to be elucidated; this problem concerns the dynamics of non-Boussinesq releases relating to large differences between the densities of the buoyant and the ambient fluids. We have investigated this problem theoretically, by means of a simplified model of a top-hat plume in a cross-flow, and in complementary experiments by means of tests in a reduced-scale ventilated tunnel, examining releases from circular sources. Experimental results reveal: (i) the existence of two flow regimes depending on the plume Richardson number at the source $\unicode[STIX]{x1D6E4}_{i}$, one for momentum-dominated releases, $\unicode[STIX]{x1D6E4}_{i}\ll 1$, and a second for buoyancy-dominated releases, $\unicode[STIX]{x1D6E4}_{i}\gg 1$, with a smooth transition between the two; and (ii) the presence of relevant non-Boussinesq effects only for momentum-dominated releases. All these features can be conveniently predicted by the plume-based model, whose validity is, strictly speaking, limited to releases issuing from ‘small’ sources in ‘weak’ ventilation flows. Analytical solutions of the model are generally in good agreement with the experimental data, even for values of the governing parameters that are beyond the range of validity for the model. The solutions aid to clarify the effect of the source radius, and reveal interesting behaviours in the limits $\unicode[STIX]{x1D6E4}_{i}\rightarrow 0$ and $\unicode[STIX]{x1D6E4}_{i}\rightarrow \infty$. These findings support the adoption of simplified models to simulate light gas releases in confined ventilated spaces.

A Simple Fluid/Structure and Structure/Structure Interaction Problem in Flow-Induced Vibration

2002 ◽  
Author(s):  
Y. Liu ◽  
R. M. C. So ◽  
Y. L. Lau
Keyword(s):  
Vortex Formation ◽  
Cross Flow ◽  
Reynolds Numbers ◽  
Quantitative Agreement ◽  
Splitter Plate ◽  
Flow Induced Vibration ◽  
Vibration Behavior ◽  
Interaction Problem ◽  
Plate System ◽  
Good Agreement

It is known that a splitter plate can moderate the vortex formation behind a cylinder, and consequently the vibration behavior of the cylinder and the plate. This paper uses the standard k-ε model and a modified wall function to simulate the flow-induced vibration of a 2D cylinder-plate system in a cross flow. Good agreement between available measurements and calculations is obtained for a single cylinder in a cross flow at Reynolds numbers up to 105. The flow-induced vibration of a cylinder-plate system in a cross flow is attempted using the same numerical method. It is possible to replicate the vibration behavior for the cylinder and the splitter plate, even though quantitative agreement with measurements is not obtained.

Sign in / Sign up

Export Citation Format

Share Document