On the Challenge of Determining the Surge Limit of Turbocharger Compressors: Part 1 – Experimental and Numerical Analysis of the Operating Limits

2021 ◽  
Author(s):  
T. Dielenschneider ◽  
J. Ratz ◽  
S. Leichtfuß ◽  
H.-P. Schiffer ◽  
W. Eißler
Keyword(s):  
System Approach ◽  
High Accuracy ◽  
Automotive Applications ◽  
Compressor Wheel ◽  
Outlet Pressure ◽  
Benchmark Data ◽  
Operating Limits ◽  
Experimental Pressure ◽  
Key Parameter

Abstract The surge limit of compressors is one key parameter in the design process of modern turbocharger compressors for automotive applications. Since the compressor is operated close to the surge limit, the determination of the surge limit is of high importance. Unfortunately, the determination of the surge limit with any numerical method with high accuracy is still an unsolved challenge. The numerical surge limit is often determined by the operating point with the minimum converged mass flow rate. But, as this investigation will clearly show, this cannot be used as a surge limit of the investigated compressor configuration. In this paper it will be shown that a more differentiated approach is required when it comes to operating limits. Especially, two different operating limits can be determined. A methodology for the determination of each limit will be presented. One is based on the system approach defined by Greitzer and the other one is based on the analysis of the low momentum fluid in the shroud region of the compressor wheel. Finally, experimental data will be used as benchmark data for both limits. The determination of the experimental surge limit is based on the analysis of transient experimental pressure signals. This is achieved through a fourier analysis of the unsteady compressor outlet pressure signal for transient surge runs.

scholarly journals New automatic minidisk infiltrometer: design and testing

2015 ◽  
Vol 63 (2) ◽  
pp. 110-116 ◽  
Author(s):  
Vladimír Klípa ◽  
Michal Sněhota ◽  
Michal Dohnal
Keyword(s):  
Hydraulic Conductivity ◽  
Field Testing ◽  
High Accuracy ◽  
Unsaturated Hydraulic Conductivity ◽  
Cumulative Infiltration ◽  
Flow Through ◽  
Design And Testing ◽  
Recording Change ◽  
Key Parameter

Abstract Soil hydraulic conductivity is a key parameter to predict water flow through the soil profile. We have developed an automatic minidisk infiltrometer (AMI) to enable easy measurement of unsaturated hydraulic conductivity using the tension infiltrometer method in the field. AMI senses the cumulative infiltration by recording change in buoyancy force acting on a vertical solid bar fixed in the reservoir tube of the infiltrometer. Performance of the instrument was tested in the laboratory and in two contrasting catchments at three sites with different land use. Hydraulic conductivities determined using AMI were compared with earlier manually taken readings. The results of laboratory testing demonstrated high accuracy and robustness of the AMI measurement. Field testing of AMI proved the suitability of the instrument for use in the determination of sorptivity and near saturated hydraulic conductivity

Determination of the Prospective Processed Cacao Product and Calculation of the Added Value in Agro-Tourism Based on Cacao Agroindustry in Pidie Jaya Regency

2018 ◽  
Vol 22 (1) ◽  
pp. 33-42
Author(s):  
◽  
Tajuddin Bantacut ◽  
Sapta Raharja
Keyword(s):  
System Approach ◽  
Added Value ◽  
Assessment Criteria ◽  
Cocoa Bean ◽  
Cocoa Beans ◽  
Bayes Method ◽  
Cocoa Products ◽  
Processed Products ◽  
Derivative Products

Abstract Utilization of cocoa bean to be a derivative products in industrial is wide enough, that it is necessary to determine the priority of the processed products development. This study aimed to determine the prospective processed cocoa products with a system approach using Bayes method and assessed the potential of added value by using Hayami method. Based on several assessment criteria indicated that chocolate bar is the priority product that needs to be developed and followed by several other processed products. This development was able to produce the added value of Rp 135.000 per kg of cocoa beans. Result indicated that by processing the cocoa beans into chocolate bar could provide a considerable income for the businessman.

scholarly journals The Degree of Oxidation of Graphene Oxide

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 560
Author(s):  
Alexandra Carvalho ◽  
Mariana C. F. Costa ◽  
Valeria S. Marangoni ◽  
Pei Rou Ng ◽  
Thi Le Hang Nguyen ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Ab Initio ◽  
State Of The Art ◽  
High Accuracy ◽  
Precise Determination ◽  
Photoemission Spectroscopy ◽  
Pristine Graphene ◽  
X Ray ◽  
Degree Of Oxidation

We show that the degree of oxidation of graphene oxide (GO) can be obtained by using a combination of state-of-the-art ab initio computational modeling and X-ray photoemission spectroscopy (XPS). We show that the shift of the XPS C1s peak relative to pristine graphene, ΔEC1s, can be described with high accuracy by ΔEC1s=A(cO−cl)2+E0, where c0 is the oxygen concentration, A=52.3 eV, cl=0.122, and E0=1.22 eV. Our results demonstrate a precise determination of the oxygen content of GO samples.

Electrochemical device based on nonspecific DNAzyme for the high-accuracy determination of Ca2+ with Pb2+ interference

2020 ◽  
pp. 107732
Author(s):  
Hui Wang ◽  
Qingyao Luo ◽  
Yiguang Zhao ◽  
Xuemei Nan ◽  
Fan Zhang ◽  
...  
Keyword(s):  
High Accuracy ◽  
Electrochemical Device ◽  
Accuracy Determination

scholarly journals A Machine Vision Approach for Bioreactor Foam Sensing

2021 ◽  
pp. 247263032110088
Author(s):  
Jonas Austerjost ◽  
Robert Söldner ◽  
Christoffer Edlund ◽  
Johan Trygg ◽  
David Pollard ◽  
...  
Keyword(s):  
Machine Learning ◽  
Machine Vision ◽  
State Of The Art ◽  
Low Cost ◽  
High Accuracy ◽  
Consumer Electronics ◽  
Learning System ◽  
Automotive Applications ◽  
Fine Grained

Machine vision is a powerful technology that has become increasingly popular and accurate during the last decade due to rapid advances in the field of machine learning. The majority of machine vision applications are currently found in consumer electronics, automotive applications, and quality control, yet the potential for bioprocessing applications is tremendous. For instance, detecting and controlling foam emergence is important for all upstream bioprocesses, but the lack of robust foam sensing often leads to batch failures from foam-outs or overaddition of antifoam agents. Here, we report a new low-cost, flexible, and reliable foam sensor concept for bioreactor applications. The concept applies convolutional neural networks (CNNs), a state-of-the-art machine learning system for image processing. The implemented method shows high accuracy for both binary foam detection (foam/no foam) and fine-grained classification of foam levels.

Based on Atomic Spectrometry for the Determination of Titanium Element in Molten Steel

2012 ◽  
Vol 622-623 ◽  
pp. 1528-1531
Author(s):  
Cui Hong Ma ◽  
Wei Qiang Zhang
Keyword(s):  
Molten Steel ◽  
Emission Spectroscopy ◽  
Atomic Emission ◽  
Lag Time ◽  
High Accuracy ◽  
Atomic Spectrometry ◽  
Atomic Emission Spectrometry ◽  
Emission Spectrometry ◽  
Important Significance

Atomic emission spectrometry with high accuracy, short lag time, and low detection limit, it has been widely applied in various fields. The application of atomic emission spectrometry in the converter steelmaking process has an important significance to improve the smelting of speed and steel quality. This article describes the principle of atomic emission spectroscopy (AES) analysis. Spectra obtained by the experimental for qualitative analysis, detected molten steel containing titanium element.

scholarly journals High accuracy determination of the thermal properties of supported 2D materials

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
Jarosław Judek ◽  
Arkadiusz P. Gertych ◽  
Michał Świniarski ◽  
Anna Łapińska ◽  
Anna Dużyńska ◽  
...  
Keyword(s):  
Thermal Properties ◽  
2D Materials ◽  
High Accuracy ◽  
Accuracy Determination

DIGITAL ZENITH CAMERA FOR VERTICAL DEFLECTION DETERMINATION

2012 ◽  
Vol 38 (4) ◽  
pp. 123-129 ◽  
Author(s):  
Māris Abele ◽  
Jānis Balodis ◽  
Inese Janpaule ◽  
Ieva Lasmane ◽  
Augusts Rubans ◽  
...  
Keyword(s):  
Data Processing ◽  
Digital Imaging ◽  
High Accuracy ◽  
Reference Star ◽  
Research Groups ◽  
Vertical Deflection ◽  
Digital Imaging Technology ◽  
Prototype Instrument ◽  
Automated Determination

Recent accomplishments in advancement of accurate astrometric reference star catalogues, development of digital imaging technology, high accuracy tiltmeter technology, and geocentric coordinate availability provided by GNSS, have made possible accurate, fast and automated determination of vertical deflections using astrometric methods. Zenith cameras for this kind of measurements have been developed or are being developed by several research groups. The paper describes a research project by Institute of Geodesy and Geoinformation, intended to design a portable digital zenith camera for vertical deflection determination with 0.1” expected accuracy. Camera components are described, proposed data processing algorithm and preliminary results, obtained with prototype instrument, are presented.

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