Programs for Computation of Velocities and Streamlines on a Blade-to-Blade Surface of a Turbomachine

1969 ◽  
Author(s):  
Theodore Katsanis ◽  
W. D. McNally
Keyword(s):  
Experimental Data ◽  
Flow Problem ◽  
Flow Direction ◽  
Two Dimensional ◽  
Blade Surface ◽  
Stream Channel ◽  
Numerical Examples ◽  
Through Flow ◽  
Channel Thickness ◽  
Finite Difference Solution

This paper describes Fortran programs that give the solution to the two-dimensional, subsonic, nonviscous flow problem on a blade-to-blade surface of revolution of a turbomachine. Flow may be axial, radial, or mixed. There may be a change in stream channel thickness in the through-flow direction. Either single, tandem, or slotted blades may be handled as well as blade rows with splitter vanes. Also, small regions may be magnified to give more detail where desired, such as around a leading or trailing edge or through a slot. The method is based on a finite difference solution of the stream function equations. Numerical examples are shown to illustrate the type of blades which can be analyzed, and to show results which can be obtained. Results are compared with experimental data.

Straight-Walled, Two-Dimensional Diffusers—Transitory Stall and Peak Pressure Recovery

1980 ◽  
Vol 102 (3) ◽  
pp. 275-282 ◽  
Author(s):  
J. Ashjaee ◽  
J. P. Johnston
Keyword(s):  
Experimental Data ◽  
Reynolds Number ◽  
Mach Number ◽  
Aspect Ratio ◽  
Peak Pressure ◽  
Flow Direction ◽  
Prediction Method ◽  
Pressure Recovery ◽  
Two Dimensional ◽  
Large Aspect Ratio

Straight-walled, two-dimensional diffusers of large aspect ratio were investigated experimentally for the purpose of studying the regime of incipient transitory stall, the location of the geometry of peak diffuser pressure recovery. Twelve symmetric diffusers of constant nondimensional length (L/W1 = 15) with total included angles ranging from 4 to 24 degrees, covering attached, intermittently detaching, and unsteady detached flows were examined. Tests were run at one inlet blockage, 2δ1 / W1 = 0.027, and at an inlet Reynolds number of U1 W1/ν = 2.2 × 105 with air flow at low inlet Mach number. Pressure recovery and flow direction intermittency were obtained along the diffuser walls. An objective comparison of the UIM method of Ghose and Kline and an improved prediction method [Appendix] was performed with respect to these new experimental data. Some new conclusions are drawn concerning the nature of the flow in the vicinity of peak pressure recovery.

Aero-thermal coupled through-flow method for cooled turbines with new cooling model

2017 ◽  
Vol 232 (3) ◽  
pp. 254-265 ◽  
Author(s):  
Wei Ba ◽  
Xuesong Li ◽  
Xiaodong Ren ◽  
Chunwei Gu
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Operating Conditions ◽  
Internal Cooling ◽  
Blade Surface ◽  
Flow Method ◽  
Cooling Channels ◽  
Through Flow ◽  
History Of ◽  
Cooling Model

The aero-thermal–coupled phenomenon is significant in modern cooled turbines, and an aero-thermal coupled through-flow method has previously been developed by the authors for considering the influence of heat transfer and coolant mixing in through-flow design. However, the original cooling model is not capable of calculating the distribution of the coolant mass flow rate and pressure loss in complex cooling structures. Therefore, in this paper, a one-dimensional flow calculation for the internal coolant is introduced into the heat transfer calculation to further improve the through-flow cooling model. Based on various empirical correlations, the cooling model can be used to simulate different cooling structures, such as ribbed channels and cooling holes. Three operating conditions were selected for verification of the NASA-C3X vane, which has 10 internal radial cooling channels. The calculated Nusselt number of internal cooling channels strongly agrees with the experimental data, and the predicted blade surface pressure and temperature distributions at mid span are also in good agreement with the experimental data. The convergence history of the meridional velocity and blade surface temperature demonstrates effective convergence properties. Therefore, the aero-thermal–coupled through-flow method with the new cooling model can provide a reliable tool for cooled turbine through-flow design and analysis.

Modelling of Moisture Movement in Wood during Outdoor Storage

2001 ◽  
Vol 6 (2) ◽  
pp. 3-14 ◽  
Author(s):  
R. Baronas ◽  
F. Ivanauskas ◽  
I. Juodeikienė ◽  
A. Kajalavičius
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Climatic Conditions ◽  
Two Dimensional ◽  
Moisture Movement ◽  
Finite Difference Technique ◽  
Long Term Storage ◽  
Space Formulation ◽  
Term Storage

A model of moisture movement in wood is presented in this paper in a two-dimensional-in-space formulation. The finite-difference technique has been used in order to obtain the solution of the problem. The model was applied to predict the moisture content in sawn boards from pine during long term storage under outdoor climatic conditions. The satisfactory agreement between the numerical solution and experimental data was obtained.

Temperature field evaluation of a two-dimensional partial heat flow problem through Green's Functions

2019 ◽  
Author(s):  
Guilherme Ramalho Costa ◽  
José Aguiar santos junior ◽  
José Ricardo Ferreira Oliveira ◽  
Jefferson Gomes do Nascimento ◽  
Gilmar Guimaraes
Keyword(s):  
Temperature Field ◽  
Heat Flow ◽  
Green's Functions ◽  
Flow Problem ◽  
Green’S Functions ◽  
Field Evaluation ◽  
Two Dimensional

scholarly journals Modelling Weirs in Two-Dimensional Shallow Water Models

Water ◽  
2021 ◽  
Vol 13 (16) ◽  
pp. 2152
Author(s):  
Gonzalo García-Alén ◽  
Olalla García-Fonte ◽  
Luis Cea ◽  
Luís Pena ◽  
Jerónimo Puertas
Keyword(s):  
Experimental Data ◽  
Shallow Water ◽  
Shallow Water Equations ◽  
Water Model ◽  
Two Dimensional ◽  
Shallow Water Model ◽  
Experimental Dataset ◽  
River Hydraulics ◽  
Shallow Water Models ◽  
Water Models

2D models based on the shallow water equations are widely used in river hydraulics. However, these models can present deficiencies in those cases in which their intrinsic hypotheses are not fulfilled. One of these cases is in the presence of weirs. In this work we present an experimental dataset including 194 experiments in nine different weirs. The experimental data are compared to the numerical results obtained with a 2D shallow water model in order to quantify the discrepancies that exist due to the non-fulfillment of the hydrostatic pressure hypotheses. The experimental dataset presented can be used for the validation of other modelling approaches.

Compressor Performance 2D Modelling at Reverse Flow Conditions

2010 ◽  
Author(s):  
L. Gallar ◽  
I. Tzagarakis ◽  
V. Pachidis ◽  
R. Singh
Keyword(s):  
Experimental Data ◽  
Reverse Flow ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Engine Performance ◽  
Two Dimensional ◽  
Flow Conditions ◽  
Compressor Surge ◽  
Compressor Performance ◽  
Shaft Failure

After a shaft failure the compression system of a gas turbine is likely to surge due to the heavy vibrations induced on the engine after the breakage. Unlike at any other conditions of operation, compressor surge during a shaft over-speed event is regarded as desirable as it limits the air flow across the engine and hence the power available to accelerate the free turbine. It is for this reason that the proper prediction of the engine performance during a shaft over-speed event claims for an accurate modelling of the compressor operation at reverse flow conditions. The present study investigates the ability of the existent two dimensional algorithms to simulate the compressor performance in backflow conditions. Results for a three stage axial compressor at reverse flow were produced and compared against stage by stage experimental data published by Gamache. The research shows that due to the strong radial fluxes present over the blades, two dimensional approaches are inadequate to provide satisfactory results. Three dimensional effects and inaccuracies are accounted for by the introduction of a correction parameter that is a measure of the pressure loss across the blades. Such parameter is tailored for rotors and stators and enables the satisfactory agreement between calculations and experiments in a stage by stage basis. The paper concludes with the comparison of the numerical results with the experimental data supplied by Day on a four stage axial compressor.

scholarly journals An experimental and theoretical investigation of particle–wall impacts in a T-junction

2013 ◽  
Vol 727 ◽  
pp. 236-255 ◽  
Author(s):  
D. Vigolo ◽  
I. M. Griffiths ◽  
S. Radl ◽  
H. A. Stone
Keyword(s):  
Flow Direction ◽  
Three Dimensional ◽  
Stokes Number ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Viscous Boundary Layer ◽  
Particle Tracing ◽  
Two Dimensional Model ◽  
Viscous Boundary ◽  
The Impact

AbstractUnderstanding the behaviour of particles entrained in a fluid flow upon changes in flow direction is crucial in problems where particle inertia is important, such as the erosion process in pipe bends. We present results on the impact of particles in a T-shaped channel in the laminar–turbulent transitional regime. The impacting event for a given system is described in terms of the Reynolds number and the particle Stokes number. Experimental results for the impact are compared with the trajectories predicted by theoretical particle-tracing models for a range of configurations to determine the role of the viscous boundary layer in retarding the particles and reducing the rate of collision with the substrate. In particular, a two-dimensional model based on a stagnation-point flow is used together with three-dimensional numerical simulations. We show how the simple two-dimensional model provides a tractable way of understanding the general collision behaviour, while more advanced three-dimensional simulations can be helpful in understanding the details of the flow.

A Viscous-Inviscid Interaction Procedure—Part 1: Method for Computing Two-Dimensional Incompressible Separated Channel Flows

1986 ◽  
Vol 108 (1) ◽  
pp. 64-70 ◽  
Author(s):  
O. K. Kwon ◽  
R. H. Pletcher
Keyword(s):  
Experimental Data ◽  
Finite Difference ◽  
Turbulent Flows ◽  
Inviscid Flow ◽  
Companion Paper ◽  
Separated Flows ◽  
Two Dimensional ◽  
Boundary Layer Equations ◽  
Interaction Scheme ◽  
Laminar And Turbulent Flows

A viscous-inviscid interaction scheme has been developed for computing steady incompressible laminar and turbulent flows in two-dimensional duct expansions. The viscous flow solutions are obtained by solving the boundary-layer equations inversely in a coupled manner by a finite-difference scheme; the inviscid flow is computed by numerically solving the Laplace equation for streamfunction using an ADI finite-difference procedure. The viscous and inviscid solutions are matched iteratively along displacement surfaces. Details of the procedure are presented in the present paper (Part 1), along with example applications to separated flows. The results compare favorably with experimental data. Applications to turbulent flows over a rearward-facing step are described in a companion paper (Part 2).

scholarly journals ONSHORE-OFFSHORE SEDIMENT MOVEMENT ON A BEACH

1978 ◽  
Vol 1 (16) ◽  
pp. 87 ◽  
Author(s):  
P. Nielsen ◽  
I.A. Svensen ◽  
C. Staub
Keyword(s):  
Experimental Data ◽  
Diffusion Coefficient ◽  
Oscillatory Flow ◽  
Sediment Flux ◽  
Three Dimensions ◽  
Two Dimensional ◽  
Present Formulation ◽  
Exact Analytical Solutions ◽  
Net Flux ◽  
Loose Sediments

A theoretical model is developed for the movement of loose sediments in oscillatory flow with or without a net current. In the present formulation the model is two-dimensional, but may readily be extended to three dimensions. It is assumed that all movement of sediments occurs in suspension, and exact analytical solutions are given for the time variation of the concentration profile, the instantaneous sediment flux and the net flux of sediment over a wave period. The model requires as empirical input a diffusion coefficient e and pick-up function p(t), for which experimental data are presented. Two examples are discussed in detail, illustrating important aspects of the onshore-offshore sediment motion.

scholarly journals Numerical Analysis of Unsteady Laminar Flow past a Pentagonal Obstacle

2021 ◽  
Vol 10 (2) ◽  
pp. 968-974
Keyword(s):  
Laminar Flow ◽  
Flow Direction ◽  
Rectangular Channel ◽  
Time Frame ◽  
Two Dimensional ◽  
Fluid Inertia ◽  
Time Step ◽  
The Face ◽  
Computational Fluid Dynamics Cfd ◽  
Current Article

The current article dispenses the numerical investigation of a two dimensional unsteady laminar flow of incompressible fluid passing a regular pentagonal obstacle in an open rectangular channel. The centre of attention of this work is the comparison of drag coefficients estimated for two distinct cases based on the orientation of face and corner of an obstacle against the flow direction. The numerical results shows that the corner – oriented obstacle bring about 42% larger value of drag coefficient at Re = 500 than face – oriented obstacle. The substantial growth in the expanse of vortex behind obstacle (presented as a function of fluid inertia 25 < Re < 500) is analyzed through the contours and streamline patterns of velocity field. The two eddies in the downstream become entirely unsymmetrical at Re = 500 for both the cases, whereas; the flow separation phenomena occurs a bit earlier in the face – oriented case at Re = 250. Two dimensional Pressure – Based – Segregated solver is employed to model the governing equations written in velocity and pressure fields. The numerical simulations of unsteady flow are presented for 50 seconds time frame with time step 0.01 by using one of the best available commercial based Computational Fluid Dynamics (CFD) software, ANSYS 15.0.

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