Improvements to the Ainley-Mathieson Method of Turbine Performance Prediction

1970 ◽  
Vol 92 (3) ◽  
pp. 252-256 ◽  
Author(s):  
J. Dunham ◽  
P. M. Came
Keyword(s):  
Performance Prediction ◽  
Tip Clearance ◽  
Project Work ◽  
Preliminary Design ◽  
Design Work ◽  
Turbine Performance ◽  
Wide Range ◽  
Blade Row ◽  
Loss Prediction ◽  
Made In

In 1951 Ainley and Mathieson published a method of predicting the design and off-design performance of an axial turbine (British ARC, R & M 2974). The flow and hence the losses were calculated at a single “reference diameter” for each blade row. This method has been widely used ever since. A critical review of the method has been made, based on detailed comparisons between the measured and predicted performance of a wide range of modern turbines. As a result, improvements have been made in the formulas for secondary loss and tip clearance loss prediction. The accuracy of the improved method has been assessed. Despite its relatively simple approach, it is believed that it will remain of great value in project work and preliminary design work.

Using CFD to Enhance the Preliminary Design of High-Pressure Steam Turbines

2013 ◽  
Author(s):  
Juri Bellucci ◽  
Federica Sazzini ◽  
Filippo Rubechini ◽  
Andrea Arnone ◽  
Lorenzo Arcangeli ◽  
...  
Keyword(s):  
High Pressure ◽  
Steam Turbine ◽  
Design Tool ◽  
Tip Clearance ◽  
Large Set ◽  
Preliminary Design ◽  
Steam Turbines ◽  
High Pressure Steam ◽  
Wide Range ◽  
Pressure Steam

This paper focuses on the use of the CFD for improving a steam turbine preliminary design tool. Three-dimensional RANS analyses were carried out in order to independently investigate the effects of profile, secondary flow and tip clearance losses, on the efficiency of two high-pressure steam turbine stages. The parametric study included geometrical features such as stagger angle, aspect ratio and radius ratio, and was conducted for a wide range of flow coefficients to cover the whole operating envelope. The results are reported in terms of stage performance curves, enthalpy loss coefficients and span-wise distribution of the blade-to-blade exit angles. A detailed discussion of these results is provided in order to highlight the different aerodynamic behavior of the two geometries. Once the analysis was concluded, the tuning of a preliminary steam turbine design tool was carried out, based on a correlative approach. Due to the lack of a large set of experimental data, the information obtained from the post-processing of the CFD computations were applied to update the current correlations, in order to improve the accuracy of the efficiency evaluation for both stages. Finally, the predictions of the tuned preliminary design tool were compared with the results of the CFD computations, in terms of stage efficiency, in a broad range of flow coefficients and in different real machine layouts.

Axial Turbine Performance Evaluation. Part B—Optimization With and Without Constraints

1968 ◽  
Vol 90 (4) ◽  
pp. 349-359 ◽  
Author(s):  
O. E. Balje´ ◽  
R. L. Binsley
Keyword(s):  
Reynolds Number ◽  
Performance Evaluation ◽  
Reference Value ◽  
Tip Clearance ◽  
Strong Function ◽  
Turbine Performance ◽  
Wide Range ◽  
Leakage Area ◽  
Partial Admission ◽  
Specific Speed

The maximum obtainable efficiency and associated geometry have been calculated based on the use of generalized loss correlations from Part A and are presented for full and partial admission turbines over a wide range of specific speeds. The calculated effects of varying values of Reynolds number, tip clearance, and trailing edge thickness on turbine performance are presented. Because of the anticipated difficulty in fabricating some of the optimum geometries calculated, the effects of using nonoptimum values of geometric parameters on attainable efficiency have also been investigated. The derating factor for machine Reynolds number is shown to be a strong function of specific speed, varying from 0.96 at a specific speed of 100, to 0.6 at a specific speed of 3, when Reynolds number is 105 compared to a reference value of 106. The derating factor for tip clearance is shown to be similar to what would be expected if the clearance area were considered as a leakage area. The use of blade heights, blade numbers, rotor exit angles, and degrees of reaction varying from the optimum by 25 percent produce maximum derating factors of 0.99, 0.98, 0.985, and 0.97, respectively, when compared to full optimum values.

scholarly journals Flow and Fast Fourier Transform Analyses for Tip Clearance Effect in an Operating Kaplan Turbine

Energies ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 264 ◽  
Author(s):  
Hyoung-Ho Kim ◽  
Md Rakibuzzaman ◽  
Kyungwuk Kim ◽  
Sang-Ho Suh
Keyword(s):  
Fourier Transform ◽  
Fast Fourier Transform ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Tip Clearance Flow ◽  
Kaplan Turbine ◽  
Turbine Performance ◽  
Wide Range ◽  
Clearance Flow ◽  
Fft Analysis

The Kaplan turbine is an axial propeller-type turbine that can simultaneously control guide vanes and runner blades, thus allowing its application in a wide range of operations. Here, turbine tip clearance plays a crucial role in turbine design and operation as high tip clearance flow can lead to a change in the flow pattern, resulting in a loss of efficiency and finally the breakdown of hydro turbines. This research investigates tip clearance flow characteristics and undertakes a transient fast Fourier transform (FFT) analysis of a Kaplan turbine. In this study, the computational fluid dynamics method was used to investigate the Kaplan turbine performance with tip clearance gaps at different operating conditions. Numerical performance was verified with experimental results. In particular, a parametric study was carried out including the different geometrical parameters such as tip clearance between stationary and rotating chambers. In addition, an FFT analysis was performed by monitoring dynamic pressure fluctuation on the rotor. Here, increases in tip clearance were shown to occur with decreases in efficiency owing to unsteady flow. With this study’s focus on analyzing the flow of the tip clearance and its effect on turbine performance as well as hydraulic efficiency, it aims to improve the understanding on the flow field in a Kaplan turbine.

Unsteady Performance Prediction of a Single Entry Mixed Flow Turbine Using 1-D Gas Dynamic Code Extended With Meanline Model

2012 ◽  
Author(s):  
Meng Soon Chiong ◽  
Srithar Rajoo ◽  
Alessandro Romagnoli ◽  
Ricardo Martinez-Botas
Keyword(s):  
Performance Prediction ◽  
Computational Models ◽  
Power Prediction ◽  
Mixed Flow ◽  
Pulse Flow ◽  
Turbine Performance ◽  
Gas Dynamic ◽  
Wide Range ◽  
Single Entry ◽  
Turbine Model

Turbochargers are widely regarded as one of the most promising enabling technology for engine downsizing, in the aim to achieve better specific fuel consumption, thermal efficiency and most importantly carbon reduction. The increasing demand for higher quality engine-turbocharger matching, leads to the development of computational models capable of predicting the unsteady behaviour of a turbocharger turbine when subjected to pulsating inlet flow. Due to the wide range of engine loads and speed variations, an automotive turbocharger turbine model must be able to render all the frequency range of a typical exhaust pulse flow. A purely one-dimensional (1-D) turbine model is capable of good unsteady swallowing capacity prediction, provided it is accurately validated. However, the unsteady turbine power evaluation still heavily relies on the quasi-steady assumption. On the other hand, meanline model is capable of resolving the turbine work output but it is limited to steady state flow due to its zero dimensional nature. This paper explores an alternative methodology to realize turbine unsteady power prediction in 1-D by integrating these two independent modelling methods. A single entry mixed-flow turbine is first modelled using 1-D gas dynamic method to solve the unsteady flow propagation in turbine volute while the instantaneous turbine power is subsequently evaluated using a mean-line model. The key in the effectiveness of this methodology relies on the synchronization of the flow information with different time-scales. In addition to the turbine performance parameters, the common level of unsteadiness was also compared based on the Strouhal number evaluations. Comparison of the quasi-steady assumption using the experiment results was made in order to further understand the strength and weaknesses of corresponding method in unsteady turbine performance prediction. The outcomes of the simulation showed a good agreement in the shape and trend profile for the instantaneous turbine power. Meanwhile the predicted cycle-averaged value indicates a positive potential of the current turbine model to be expanded to a whole engine simulation after few minor improvements.

Performance Prediction of Centrifugal Impellers Using a Two-Zone Model

2008 ◽  
Author(s):  
Ian Britton ◽  
J. E. Donald Gauthier
Keyword(s):  
Performance Prediction ◽  
Pressure Ratio ◽  
Model Development ◽  
Computer Code ◽  
Centrifugal Impeller ◽  
Zone Model ◽  
Preliminary Design ◽  
Wide Range ◽  
Mass Flow Rates ◽  
Isentropic Efficiency

This paper outlines the methodology and theory required for the development of a computer code for the performance prediction of centrifugal impellers. The theory is blended from two main sources on two-zone model development. The equations provided show a simplified version of previous two-zone models published while maintaining a similar level of accuracy in the prediction of pressure ratio and isentropic efficiency. The idea behind the development of the algorithm is the production of an impeller map which can be used in the preliminary design phase with a minimum amount of input information, namely basic geometry which could be determined from simple design point calculations. Validation of the model was performed against compressor maps and geometries available in the literature. It was subsequently shown that with the blending of inlet, diffusion ratio and two-zone models, a centrifugal impeller model was constructed which agreed well over a wide range of rotational speeds and mass flow rates.

Exhaust Volume Dependency of Turbocharger Turbine Design for a Heavy Duty Otto Cycle Engine

2017 ◽  
Author(s):  
Nicholas Anton ◽  
Magnus Genrup ◽  
Carl Fredriksson ◽  
Per-Inge Larsson ◽  
Anders Erlandsson-Christiansen
Keyword(s):  
Simulation Software ◽  
Exhaust Manifold ◽  
Otto Cycle ◽  
Heavy Duty ◽  
Design Work ◽  
Turbine Performance ◽  
Design Variables ◽  
Starting Point ◽  
Wide Range ◽  
Turbine Design

This study is considering turbocharger turbine performance at “on-engine” conditions with respect to turbine design variables and exhaust manifold volume. The highly unsteady nature of the internal combustion engine will result in a very wide range of turbine operation, far from steady flow conditions. As most turbomachinery design work is conducted at steady state, the influence of the chosen turbine design variables on the crank-angle-resolved turbine performance will be of prime interest. In order to achieve high turbocharger efficiency with the greatest benefits for the engine, the turbine will need high efficiency at the energetic exhaust pressure pulse peak. The starting point for this paper is a target full load power curve for a heavy duty Otto-cycle engine, which will dictate an initial compressor and turbine match. Three radial turbine designs are investigated, differing with respect to efficiency characteristics, using a common compressor stage. The influence of the chosen turbine design variables considering a main contributor to unsteadiness, exhaust manifold volume, is evaluated using 1D engine simulation software. A discussion is held in conjunction with this regarding the efficiency potential of each turbine design and limitations of turbine types.

Axial Turbine Performance Evaluation. Part A—Loss-Geometry Relationships

1968 ◽  
Vol 90 (4) ◽  
pp. 341-348 ◽  
Author(s):  
O. E. Balje´ ◽  
R. L. Binsley
Keyword(s):  
Reynolds Number ◽  
Performance Evaluation ◽  
Operating Conditions ◽  
Tip Clearance ◽  
Published Data ◽  
Blade Height ◽  
Blade Number ◽  
Turbine Performance ◽  
Wide Range ◽  
Partial Admission

Generalized loss correlations for full and partial admission turbines have been derived and critically compared with recently published data. Effects included are Reynolds number, blade angles, blade height, blade number, blade trailing edge thickness, tip clearance, and reaction. These generalized loss relationships are for use in optimization of turbines over a wide range of possible operating conditions.

scholarly journals On the Performance Prediction of a Centrifugal Compressor Scaled Up

1982 ◽  
Author(s):  
T. Mashimo ◽  
I. Ariga ◽  
T. Sakai ◽  
I. Watanabe
Keyword(s):  
Centrifugal Compressor ◽  
Performance Prediction ◽  
Prediction Method ◽  
Tip Clearance ◽  
Wall Friction ◽  
Test Results ◽  
Flow Losses ◽  
Wide Range ◽  
Compressor Performance ◽  
The Individual

A centrifugal compressor performance prediction method, in which each loss generated within the compressor stage was estimated by recognizing the individual relationship with Mach number, was investigated over a wide range of sizes and types. Calculation formulae for the losses were established by analyzing test results. It was confirmed that the formulae could be applied to predict the performance levels of compressors with impeller diameters from 78 mm to 640 mm by refering to unpublished test data obtained experimentally by other researchers. From the results, it could be deduced that: (1) The wall friction losses and the secondary flow losses within the compressor decreased with increase of impeller size. (2) The leakage flow losses were found to increase when scaling up the compressor, even when tip clearance/blade height were held constant. The present paper presents a progress report of work still underway.

A Comprehensive Review on C-3 Functionalization of β-Lactams

2019 ◽  
Vol 16 (1) ◽  
pp. 3-16 ◽  
Author(s):  
Reshma Nagpal ◽  
Jitender Bhalla ◽  
Shamsher S. Bari
Keyword(s):  
Scientific Community ◽  
Organometallic Reagent ◽  
Reaction Conditions ◽  
Biological Potential ◽  
Wide Range ◽  
Economic Strategies ◽  
Synthetic Utility ◽  
Recent Advancement ◽  
Equivalent Method ◽  
Made In

Background:A lot of advancement has been made in the area of β-lactams in recent times. Most of the research is targeted towards the synthesis of novel β-lactams, their functionalization and exploring their biological potential. The C-3 functionalization of β-lactams has continued to attract considerable interest of the scientific community due to their utility as versatile intermediates in organic synthesis and their therapeutic applications. This has led to the significant increase in efforts towards developing efficient and economic strategies for C-3 functionalized β-lactams.Objective:The present review aims to highlight recent advancement made in C-3 functionalization of β-lactams.Conclusion:To summarize, functionalization of β-lactams at C-3 is an essential aspect of β-lactam chemistry in order to improve/modify its synthetic utility as well as biological potential. The C-3 carbocation equivalent method has emerged as an important and convenient strategy for C-3 functionalization of β-lactam heterocycles which provides a wide range of β-lactams viz. 3-alkylated β-lactams, 3-aryl/heteroarylated β-lactams, 3- alkoxylated β-lactams. On the other hand, base mediated functionalization of β-lactams via carbanion intermediate is another useful approach but their scope is limited by the requirement of stringent reaction conditions. In addition to this, organometallic reagent mediated α-alkylation of 3-halo/3-keto-β-lactams also emerged as interesting methods for the synthesis of functionalized β-lactams having good yields and diastereoselectivities.

scholarly journals Multiplexed Genetic Analysis Using an Expanded Genetic Alphabet

2004 ◽  
Vol 50 (11) ◽  
pp. 2019-2027 ◽  
Author(s):  
Scott C Johnson ◽  
David J Marshall ◽  
Gerda Harms ◽  
Christie M Miller ◽  
Christopher B Sherrill ◽  
...  
Keyword(s):  
Newborn Screening ◽  
Cftr Gene ◽  
Transmembrane Conductance Regulator ◽  
Transmembrane Conductance ◽  
Genetic Tests ◽  
Wide Range ◽  
Additional Base ◽  
A Prospective Study ◽  
Cystic Fibrosis Transmembrane ◽  
Made In

Abstract Background: All states require some kind of testing for newborns, but the policies are far from standardized. In some states, newborn screening may include genetic tests for a wide range of targets, but the costs and complexities of the newer genetic tests inhibit expansion of newborn screening. We describe the development and technical evaluation of a multiplex platform that may foster increased newborn genetic screening. Methods: MultiCode® PLx involves three major steps: PCR, target-specific extension, and liquid chip decoding. Each step is performed in the same reaction vessel, and the test is completed in ∼3 h. For site-specific labeling and room-temperature decoding, we use an additional base pair constructed from isoguanosine and isocytidine. We used the method to test for mutations within the cystic fibrosis transmembrane conductance regulator (CFTR) gene. The developed test was performed manually and by automated liquid handling. Initially, 225 samples with a range of genotypes were tested retrospectively with the method. A prospective study used samples from >400 newborns. Results: In the retrospective study, 99.1% of samples were correctly genotyped with no incorrect calls made. In the perspective study, 95% of the samples were correctly genotyped for all targets, and there were no incorrect calls. Conclusions: The unique genetic multiplexing platform was successfully able to test for 31 targets within the CFTR gene and provides accurate genotype assignments in a clinical setting.

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