One-Dimensional Performance Prediction of Subsonic Vaned Diffusers

1999 ◽  
Vol 122 (3) ◽  
pp. 494-504 ◽  
Author(s):  
Beat Ribi ◽  
Peter Dalbert
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Performance Prediction ◽  
Continuity Equation ◽  
Pressure Rise ◽  
Prediction Method ◽  
Momentum Thickness ◽  
Dimensional Theory ◽  
Integral Boundary ◽  
One Dimensional

A simple one-dimensional theory to predict the performance of a diffuser using as few empirical factors as possible is presented. The prediction method uses two empirical functions to assess both the pressure recovery and the losses. The functions have been calibrated from experimental data from the company’s standard diffusers. The method is, however, adaptable for any type of subsonic vaned diffusers, provided that the empirical functions can be calibrated from measurements. The pressure rise in the diffuser is calculated from the continuity equation, taking into account the blockage, while the losses are determined by means of displacement and momentum thickness. These values are calculated at design point from an integral boundary layer calculation. To take into account the influence of flow separation at off-design, the calculated displacement and momentum thickness are increased according to empirical functions. When designing a new impeller, the method provides a simple way to evaluate the diffuser, resulting in the best combination in terms of efficiency and range. It further provides a simple means of estimating the change to be expected in a known stage performance characteristic due to a modification of the diffuser geometry.[S0889-504X(00)01703-7]

One-Dimensional Performance Prediction of Subsonic Vaned Diffusers

1999 ◽  
Author(s):  
Beat Ribi ◽  
Peter Dalbert
Keyword(s):  
Experimental Data ◽  
Boundary Layer ◽  
Performance Prediction ◽  
Performance Characteristic ◽  
Continuity Equation ◽  
Pressure Rise ◽  
Prediction Method ◽  
Momentum Thickness ◽  
Integral Boundary ◽  
One Dimensional

A simple 1-d-theory to predict the performance of a diffuser using as few empirical factors as possible is presented. The prediction method uses two empirical functions to assess both the pressure recovery and the losses. The functions have been calibrated from experimental data from the company’s standard diffusers. The method is, however, adaptable for any type of subsonic vaned diffusers provided that the empirical functions can be calibrated from measurements. The pressure rise in the diffuser is calculated from the continuity equation taking into account the blockage, while the losses are determined by means of displacement and momentum thickness. These values are calculated at design point from an integral boundary layer calculation. To take into account the influence of flow separation at off-design the calculated displacement and momentum thickness are increased according to empirical functions. When designing a new impeller the method provides a simple way to evaluate the diffuser resulting in the best combination in terms of efficiency and range. It further provides a simple means of estimating the change to be expected in a known stage performance characteristic due to a modification of the diffuser geometry.

The Effect of Sweep on Conditions at Separation in Turbulent Boundary-Layer/Shock-Wave Interaction

1977 ◽  
Vol 28 (2) ◽  
pp. 111-122 ◽  
Author(s):  
D F Myring
Keyword(s):  
Boundary Layer ◽  
Shock Wave ◽  
Turbulent Boundary Layer ◽  
Pressure Rise ◽  
Prediction Method ◽  
Wave Interaction ◽  
Reynolds Numbers ◽  
Approximate Analysis ◽  
Integral Boundary ◽  
Shock Wave Interaction

SummaryAn approximate analysis of conditions at separation produced by turbulent boundary-layer/shock-wave interaction is presented for swept, cylindrically symmetric flows. An integral boundary-layer prediction method is used, incorporating Johnston crossflow profiles. The results indicate a marked reduction in pressure rise required to produce separation as sweep is increased. At low Reynolds numbers the skin friction at separation is inferred to be small, whereas at higher Reynolds numbers the presence of a vigorous streamwise flow may be detected. In the limiting case of zero sweep, or two-dimensional flow, predictions using the approximate analysis are shown to compare well with experimental results of pressure rise to separation.

Improving a one-dimensional centrifugal compressor performance prediction method

2005 ◽  
Vol 219 (8) ◽  
pp. 653-659 ◽  
Author(s):  
E Swain
Keyword(s):  
Centrifugal Compressor ◽  
Performance Prediction ◽  
Fluid Dynamic ◽  
Three Dimensional ◽  
Axial Compressor ◽  
Prediction Method ◽  
Compressor Cascade ◽  
One Dimensional ◽  
Compressor Performance ◽  
Cfd Analyses

A one-dimensional centrifugal compressor performance prediction technique that has been available for some time is updated as a result of extracting the component performance from three-dimensional computational fluid dynamic (CFD) analyses. Confidence in the CFD results is provided by comparison of overall performance for one of the compressor examples. The extracted impeller characteristic is compared with the original impeller loss model, and this indicated that some improvement was desirable. The position of least impeller loss was determined using a traditional axial compressor cascade method, and suitable algebraic expressions were derived to match the CFD data. The merit of the approach lies with the relative ease that CFD component performance currently can be achieved and adjusting one-dimensional methods to agree with the CFD-derived models.

Prediction of the steady and non-steady flow performance of a highly loaded mixed flow turbine

1998 ◽  
Vol 212 (3) ◽  
pp. 173-184 ◽  
Author(s):  
M Abidat ◽  
M Hachemi ◽  
M K Hamidou ◽  
N C Baines
Keyword(s):  
Steady State ◽  
Performance Prediction ◽  
Internal Combustion Engines ◽  
Prediction Method ◽  
Combustion Engines ◽  
Steady State Flow ◽  
Mixed Flow ◽  
One Dimensional ◽  
Flow Equations ◽  
State Flow

This paper describes a method for predicting the performance under both turbine inlet steady state and non-steady state flow conditions of a mixed flow turbine used for turbocharged internal combustion engines. The mixed flow turbine steady state performances computed with the steady state performance prediction method are in good agreement with the experimental results obtained in the Imperial College turbocompressor cold air test rig. The unsteady state performance is computed using a one-dimensional model based on the solution of the unsteady one-dimensional flow equations. These equations are solved in the volute by a finite difference method using a four-step explicit Runge—Kutta scheme. The instantaneous volute exit condition is provided by the steady state rotor performance prediction model with the assumption of a quasi-steady state flow in the rotor. The computed instantaneous performances are in reasonable agreement with published experimental data for the same mixed flow turbine. The unsteady flow model is also used to study the effects of the frequency and the amplitude of the pulse on the performances of the mixed flow turbine.

Aerodynamic Performance Prediction of Transonic Axial Multistage Compressors Based on One-Dimensional Meanline Method

2020 ◽  
Author(s):  
Yingying Zhang ◽  
Shijie Zhang ◽  
Yunhan Xiao
Keyword(s):  
Performance Prediction ◽  
Pressure Rise ◽  
Direct Calculation ◽  
One Dimensional ◽  
Axial Compressors ◽  
Surge Margin ◽  
Multistage Compressors ◽  
Aerodynamic Parameters ◽  
And Performance ◽  
The One

Abstract The one-dimensional meanline method is of great importance for the design and performance prediction of multistage axial compressors. The models adopted in it, such as incidence, deviation and loss, considering real-fluid effects, determine whether the compressors’ operating behavior can be simulated accurately or not. This paper describes an improved meanline stage-stacking approach for the modelling of modern transonic axial multistage compressors. The improvement embodied in this study is mainly focused on deviation and surge margin prediction, which is the result of a combination of the previous models and models’ correction. One of the coefficients in the deviation angle model is corrected. A new surge model, different from the well-known maximum static pressure rise method of Koch and Smith, is introduced into this program and its advantage lies in higher accuracy and direct calculation instead of proposing a judgment criterion. Three well-documented NASA axial transonic compressors are calculated by this meanline method, and the speedlines and aerodynamic parameters are compared with the experimental data to verify the method presented in this paper. A discussion of the result then follows.

One-dimensional theory of the wave boundary layer

1993 ◽  
Vol 63 (1-2) ◽  
pp. 65-96 ◽  
Author(s):  
D. V. Chalikov ◽  
M. Yu. Belevich
Keyword(s):  
Boundary Layer ◽  
Dimensional Theory ◽  
One Dimensional ◽  
Wave Boundary Layer ◽  
Wave Boundary

Compressible Conical Diffuser Flow Using the Energy Deficit Boundary Layer Method

1975 ◽  
Vol 17 (4) ◽  
pp. 206-213
Author(s):  
J. L. Livesey ◽  
A. O. Odukwe ◽  
W. A. Kamal
Keyword(s):  
Boundary Layer ◽  
Performance Prediction ◽  
Prediction Method ◽  
Energy Deficit ◽  
Layer Method ◽  
Diffuser Flow ◽  
Conical Diffuser ◽  
Boundary Layer Method ◽  
Incompressible Boundary ◽  
Good Agreement

A performance prediction method for high inlet Mach number conical diffusers is developed, which uses the kinetic energy deficit equation in the calculation of the compressible turbulent boundary layer. A power law velocity profile is assumed together with Crocco's relation for the temperature distribution. Following Green, Morkovin's hypothesis is invoked to extend to the compressible flow the existing relations for the shear work integral originally developed for incompressible boundary layers. Comparison of the predicted results with available experimental results shows good agreement.

scholarly journals A Rapid Method for Predicting Global and Local Performance of Cascades With Special Emphasis on the Calculation of the Transition Region

1994 ◽  
Author(s):  
Umit Kus ◽  
Jacques Chauvin
Keyword(s):  
Boundary Layer ◽  
Rapid Method ◽  
Performance Prediction ◽  
Transitional Region ◽  
Extensive Literature ◽  
Integral Boundary ◽  
Local Boundary ◽  
Global Performance ◽  
Boundary Layer Method ◽  
External Turbulence

The principle of a rapid method of cascade performance prediction is presented. It is based on a strong coupling between a potential flow approach and an integral boundary layer method, and takes into account laminar, transitional and turbulent regimes as well as the separated regions. Special emphasis is given to the transitional region. In addition to a pre-existing bubble separation model and following an extensive literature survey, two transition onset and three transition length criteria have been incorporated in the method as well as a Görtler type approach. Comparison of the criteria on typical cascades show that they are relatively coherent between themselves and lead to a satisfactory prediction of the global performance for a large number of different compressor and turbine cascades among which the NACA and DCA cascades discussed in this paper. Local boundary layer performance is compared with Deutsch and Zierke’s data, where, unhappily, transition is chiefly through separation bubbles. The comparison shows the validity of Roberts ‘bubble transition model. Applying the Görtler curvature approach gives similar results to the other criteria. The global performance prediction for this case is also satisfactory. Additionally, parametric studies are carried out on the effect of external turbulence level.

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