A New Approach to Predicting Centrifugal Compressor Sideload Pressure

2002 ◽  
Author(s):  
James R. Hardin
Keyword(s):  
Test Data ◽  
Centrifugal Compressor ◽  
Total Pressure ◽  
New Method ◽  
Cfd Analysis ◽  
New Approach ◽  
Data Points

This paper presents a new method of predicting pressure in a centrifugal compressor sideload. The method is compared with results from a CFD analysis and with test data points from five different sideloads. In all cases for which the sideload exit total pressure was known, the new method predicted the total pressure within 1 percent, usually within 0.5 percent. The new method is simple enough to use in unsophisticated prediction programs or spreadsheets or even hand calculations. Furthermore, the curvature factor developed for this method illustrates how sideload geometry affects sideload pressure.

Fast and simple dataset selection for machine learning

2019 ◽  
Vol 67 (10) ◽  
pp. 833-842
Author(s):  
Timm J. Peter ◽  
Oliver Nelles
Keyword(s):  
New Method ◽  
Complex Method ◽  
Optimal Point ◽  
Point Distribution ◽  
New Approach ◽  
Original Dataset ◽  
Representative Subset ◽  
New Strategy ◽  
Data Points ◽  
Space Filling Design

Abstract The task of data reduction is discussed and a novel selection approach which allows to control the optimal point distribution of the selected data subset is proposed. The proposed approach utilizes the estimation of probability density functions (pdfs). Due to its structure, the new method is capable of selecting a subset either by approximating the pdf of the original dataset or by approximating an arbitrary, desired target pdf. The new strategy evaluates the estimated pdfs solely on the selected data points, resulting in a simple and efficient algorithm with low computational and memory demand. The performance of the new approach is investigated for two different scenarios. For representative subset selection of a dataset, the new approach is compared to a recently proposed, more complex method and shows comparable results. For the demonstration of the capability of matching a target pdf, a uniform distribution is chosen as an example. Here the new method is compared to strategies for space-filling design of experiments and shows convincing results.

scholarly journals A new method for the in vivo identification of degenerated material property ranges of the human eye: feasibility analysis based on synthetic data

2021 ◽  
Author(s):  
Stefan Muench ◽  
Mike Roellig ◽  
Daniel Balzani
Keyword(s):  
Real Time ◽  
Test Data ◽  
Synthetic Data ◽  
New Method ◽  
Data Sets ◽  
New Approach ◽  
Full Field ◽  
Material Parameters ◽  
Virtual Test

AbstractThis paper proposes a new method for in vivo and almost real-time identification of biomechanical properties of the human cornea based on non-contact tonometer data. Further goal is to demonstrate the method’s functionality based on synthetic data serving as reference. For this purpose, a finite element model of the human eye is constructed to synthetically generate full-field displacements from different data sets with keratoconus-like degradations. Then, a new approach based on the equilibrium gap method combined with a mechanical morphing approach is proposed and used to identify the material parameters from virtual test data sets. In a further step, random absolute noise is added to the virtual test data to investigate the sensitivity of the new approach to noise. As a result, the proposed method shows a relevant accuracy in identifying material parameters based on full-field displacements. At the same time, the method turns out to work almost in real time (order of a few minutes on a regular workstation) and is thus much faster than inverse problems solved by typical forward approaches. On the other hand, the method shows a noticeable sensitivity to rather small noise amplitudes rendering the method not accurate enough for the precise identification of individual parameter values. However, analysis show that the accuracy is sufficient for the identification of property ranges which might be related to diseased tissues. Thereby, the proposed approach turns out promising with view to diagnostic purposes.

A New Approach for Determining In-Situ Rock Strength While Drilling

1996 ◽  
Vol 118 (4) ◽  
pp. 249-255 ◽  
Author(s):  
L. L. Hoberock ◽  
G. J. Bratcher
Keyword(s):  
Field Experiment ◽  
Test Data ◽  
Rock Strength ◽  
New Method ◽  
Drill Bit ◽  
New Approach ◽  
Drilling Data

A new method is developed for determining rock strength while drilling with a tri-cone roller bit. The technique employs the well-known “drill-off” test, using commonly measured drilling data, and does not require knowledge of drill bit parameters. The method was evaluated with drill-off test data collected from the Gas Research Institute’s SFE (staged field experiment) well no. 4 and compared with calculated in-situ compressive rock strengths provided by Hareland (1992). The results indicate that the proposed approach produces reasonable results and is easily implemented.

A New Approach for the Analysis of Mixture Toxicity Data

1992 ◽  
Vol 26 (9-11) ◽  
pp. 2345-2348 ◽  
Author(s):  
C. N. Haas
Keyword(s):  
Quantitative Analysis ◽  
Mixture Toxicity ◽  
New Method ◽  
Metal Exposure ◽  
Positive Interactions ◽  
Toxicity Data ◽  
Data Set ◽  
New Approach ◽  
Negative Interactions

A new method for the quantitative analysis of multiple toxicity data is described and illustrated using a data set on metal exposure to copepods. Positive interactions are observed for Ni-Pb and Pb-Cr, with weak negative interactions observed for Ni-Cr.

scholarly journals New Method for Generating New Families of Distributions

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 726
Author(s):  
Lamya A. Baharith ◽  
Wedad H. Aljuhani
Keyword(s):  
Exponential Distribution ◽  
Real Data ◽  
Rate Function ◽  
New Method ◽  
Likelihood Method ◽  
Alpha Power ◽  
Unknown Parameters ◽  
Failure Rate Function ◽  
New Approach ◽  
Numerical Studies

This article presents a new method for generating distributions. This method combines two techniques—the transformed—transformer and alpha power transformation approaches—allowing for tremendous flexibility in the resulting distributions. The new approach is applied to introduce the alpha power Weibull—exponential distribution. The density of this distribution can take asymmetric and near-symmetric shapes. Various asymmetric shapes, such as decreasing, increasing, L-shaped, near-symmetrical, and right-skewed shapes, are observed for the related failure rate function, making it more tractable for many modeling applications. Some significant mathematical features of the suggested distribution are determined. Estimates of the unknown parameters of the proposed distribution are obtained using the maximum likelihood method. Furthermore, some numerical studies were carried out, in order to evaluate the estimation performance. Three practical datasets are considered to analyze the usefulness and flexibility of the introduced distribution. The proposed alpha power Weibull–exponential distribution can outperform other well-known distributions, showing its great adaptability in the context of real data analysis.

scholarly journals Genetic Algorithm Optimization of the Volute Shape of a Centrifugal Compressor

2016 ◽  
Vol 2016 ◽  
pp. 1-13 ◽  
Author(s):  
Martin Heinrich ◽  
Rüdiger Schwarze
Keyword(s):  
Numerical Model ◽  
Centrifugal Compressor ◽  
Total Pressure ◽  
Pressure Ratio ◽  
Pressure Rise ◽  
Maximum Efficiency ◽  
Algorithm Optimization ◽  
Cross Sectional ◽  
Design Variables ◽  
Design Speed

A numerical model for the genetic optimization of the volute of a centrifugal compressor for light commercial vehicles is presented. The volute cross-sectional shape is represented by cubic B-splines and its control points are used as design variables. The goal of the global optimization is to maximize the average compressor isentropic efficiency and total pressure ratio at design speed and four operating points. The numerical model consists of a density-based solver in combination with the SSTk-ωturbulence model with rotation/curvature correction and the multiple reference frame approach. The initial validation shows a good agreement between the numerical model and test bench measurements. As a result of the optimization, the average total pressure rise and efficiency are increased by over1.0%compared to the initial designs of the optimization, while the maximum efficiency rise is nearly 2.5% atm˙corr=0.19 kg/s.

Comparison of New Telescopic Video Microlaryngoscopic and Standard Microlaryngoscopic Techniques

1992 ◽  
Vol 101 (1) ◽  
pp. 51-60 ◽  
Author(s):  
Eiji Yanagisawa ◽  
Ken Yanagisawa ◽  
Jay B. Horowitz ◽  
Lawrence J. Mambrino
Keyword(s):  
Video Camera ◽  
New Method ◽  
Depth Of Field ◽  
Microscopic Technique ◽  
New Approach ◽  
Advantages And Disadvantages ◽  
Laryngeal Surgery ◽  
Valuable Method ◽  
Microlaryngeal Surgery ◽  
Television Image

A new approach to microlaryngeal surgery using a specially designed video microlaryngoscope with a rigid endoscopic telescope and an attached video camera was introduced by Kantor et al in 1990. The ability to video document and perform surgery of the larynx by viewing a high-resolution television image was demonstrated. This method was recommended over the standard microscopic technique for increased visibility with greater depth of field, unimpeded instrument access, instant documentation, and superior teaching value. The authors tried this new method and the standard microscopic technique at the same sitting on a series of patients. This paper will compare these two different techniques and discuss their advantages and disadvantages. Although the new method has many advantages, the standard microscopic technique remains as a valuable method in laryngeal surgery.

Strength of cold-formed steel shear diaphragms

1979 ◽  
Vol 6 (1) ◽  
pp. 5-17 ◽  
Author(s):  
Paul Fazio ◽  
Kinh Ha ◽  
S. Chockalingam
Keyword(s):  
Air Force ◽  
Test Data ◽  
Seismic Design ◽  
Shear Capacity ◽  
Rational Method ◽  
New Approach ◽  
Iron And Steel ◽  
Cold Formed Steel ◽  
The U.S ◽  
Steel Institute

The design of light-gage steel corrugated shear diaphragms is not yet covered by the structural codes of many countries, including Canada. The shear capacity of steel diaphragms may be predicted by various approaches currently available, namely, those proposed by: (1) the American Iron and Steel Institute; (2) the Manual of seismic design of buildings, published by the U.S. Departments of the Army, Navy, and Air Force; and (3) the recommendations outlined in the current British code. In this paper, a rational method is proposed and the application of all the above methods is illustrated with reference to a specific example. Finally, the shear strengths of many diaphragms are predicted by the new approach developed by the authors and the results are compared to test data.

The Effect of Inlet Distortion on the Performance Characteristics of a Centrifugal Compressor

1983 ◽  
Vol 105 (2) ◽  
pp. 223-230 ◽  
Author(s):  
I. Ariga ◽  
N. Kasai ◽  
S. Masuda ◽  
Y. Watanabe ◽  
I. Watanabe
Keyword(s):  
Centrifugal Compressor ◽  
Total Pressure ◽  
Performance Characteristics ◽  
Performance Tests ◽  
Velocity Measurements ◽  
Test Rig ◽  
Low Speed ◽  
Inlet Distortion ◽  
Surge Margin ◽  
The Given

The present paper concerns itself with the effects of total pressure (and thus velocity) distortion on performance characteristics and surge margin of centrifugal compressors. Both radial and circumferential distortions were investigated. The performance tests as well as the velocity measurements within the impeller passages were carried out with a low-speed compressor test rig with the inlet honeycomb as the distortion generators and compared with the case of “no distortion” as a datum. The results indicated that the inlet distortion exerted unfavorable influences on the efficiency and the surge margin of the given compressor, though the influence of the radial distortion was much stronger than that of the circumferential one. Various distortion indices were further examined in order to correlate the performance to the inlet distortion.

Inferring age from otolith measurements: a review and a new approach

2004 ◽  
Vol 61 (7) ◽  
pp. 1269-1284 ◽  
Author(s):  
RIC Chris Francis ◽  
Steven E Campana
Keyword(s):  
Simulation Experiment ◽  
Cost Benefit Analysis ◽  
Cost Benefit ◽  
New Method ◽  
Population Parameters ◽  
Benefit Analysis ◽  
Mixture Analysis ◽  
New Approach ◽  
Individual Fish ◽  
The Cost

In 1985, Boehlert (Fish. Bull. 83: 103–117) suggested that fish age could be estimated from otolith measurements. Since that time, a number of inferential techniques have been proposed and tested in a range of species. A review of these techniques shows that all are subject to at least one of four types of bias. In addition, they all focus on assigning ages to individual fish, whereas the estimation of population parameters (particularly proportions at age) is usually the goal. We propose a new flexible method of inference based on mixture analysis, which avoids these biases and makes better use of the data. We argue that the most appropriate technique for evaluating the performance of these methods is a cost–benefit analysis that compares the cost of the estimated ages with that of the traditional annulus count method. A simulation experiment is used to illustrate both the new method and the cost–benefit analysis.

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