A Global Approach in Evaluating Inlet/Engine Compatibility

1991 ◽  
Author(s):  
Frank L. Csavina ◽  
Russell K. Denney
Keyword(s):  
Statistical Approach ◽  
Aircraft Engine ◽  
Total System ◽  
Weapon Systems ◽  
Engine Model ◽  
Inlet Distortion ◽  
Surge Margin ◽  
Predicted Probability ◽  
The Given ◽  
Insight Into

Modern weapon systems demands are forcing engine designers to draw a finer line in their trades between performance and compatibility. Next generation smart engine controls also have the flexibility to optimize (real-time) either performance or compatibility knowing the flight condition and aircraft attitude. This paper presents a global statistical approach for the evaluation of installed aircraft/engine compatibility. The proposed methodology uses a Monte Carlo simulation to analyze the complex interaction of randomly occurring destabilizing events. Planned or projected aircraft operational usage and bleed and power offtake demand data are combined with data from an inlet distortion model and an engine model to predict remaining surge margin for the given operational usage. The result is a predicted probability of surge per thousand engine flight hours. Thus the procedure yields a quantitative total system or global assessment of the probability of engine surge, thereby providing designers expanded insight into inlet/engine compatibility decisions.

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.

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

1982 ◽  
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.

Mobile-Friendly Dashboards to Display Associations Between Cited-by and Similar Journals on Mobile Health Research: A Bibliometric Study (Preprint)

2018 ◽  
Author(s):  
Tsair-Wei Chien ◽  
Hsien-Yi Wang ◽  
Yang Shao ◽  
Willy Chou
Keyword(s):  
Social Network ◽  
Mobile Health ◽  
Health Research ◽  
Similarity Criteria ◽  
Network Density ◽  
Deep Insight ◽  
Density Indices ◽  
The Subject ◽  
The Given ◽  
Insight Into

BACKGROUND Researchers often spend a great deal of time and effort retrieving related journals for their studies and submissions. Authors often designate one article and then retrieve other articles that are related to the given one using PubMed’s service for finding cited-by or similar articles. However, to date, none present the association between cited-by and similar journals related to a given journal. Authors need one effective and efficient way to find related journals on the topic of mobile health research. OBJECTIVE This study aims (1) to show the related journals for a given journal by both cited-by and similarity criteria; (2) to present the association between cited-by and similarity journals related to a given journal; (3) to inspect the patterns of network density indices among clusters classified by social network analysis (SNA); (4) to investigate the feature of Kendall's coefficient(W) of concordance. METHODS We obtained 676 abstracts since 2013 from Medline based on the keywords of ("JMIR mHealth and uHealth"[Journal]) on June 30, 2018, and plotted the clusters of related journals on Google Maps by using MS Excel modules. The features of network density indices were examined. The Kendall coefficient (W) was used to assess the concordance of clusters across indices. RESULTS This study found that (1) the journals related to JMIR mHealth and uHealth are easily presented on dashboards; (2) a mild association(=0.14) exists between cited-by and similar journals related to JMIR mHealth and uHealth; (3) the median Impact Factor were 3.37 and 2.183 based on the representatives of top ten clusters grouped by the cited-by and similar journals, respectively; (4) all Kendall’s coefficients(i.e., 0.82, 0.89, 0.92, and 0.75) for the four sets of density centrality have a statistically significant concordance (p < 0.05). CONCLUSIONS SNA provides deep insight into the relationships of related journals to a given journal. The results of this research can provide readers with a knowledge and concept diagram to use with future submissions to a given journal in the subject category of Mobile Health Research. CLINICALTRIAL Not available

Aero-engine dynamic model based on an improved compact propulsion system dynamic model

2021 ◽  
pp. 095965182098408
Author(s):  
Qiangang Zheng ◽  
Yong Wang ◽  
Chongwen Jin ◽  
Haibo Zhang
Keyword(s):  
Dynamic Model ◽  
Propulsion System ◽  
System Dynamic ◽  
Inlet Temperature ◽  
System Dynamic Model ◽  
Component Level ◽  
Engine Model ◽  
Surge Margin ◽  
Aero Engine ◽  
Engine Dynamic

The modern advanced aero-engine control methods are onboard dynamic model–based algorithms. In this article, a novel aero-engine dynamic modeling method based on improved compact propulsion system dynamic model is proposed. The aero-engine model is divided into inlet, core engine, surge margin and nozzle models for establishing sub-model in the compact propulsion system dynamic model. The model of core engine is state variable model. The models of inlet, surge margin and nozzle are nonlinear models which are similar to the component level model. A new scheduling scheme for basepoint control vector, basepoint state vector and basepoint output vector which considers the change of engine total inlet temperature is proposed to improve engine model accuracy especially the steady. The online feedback correction of measurable parameters is adopted to improve the steady and dynamic accuracy of model. The modeling errors of improved compact propulsion system dynamic model remain unchanged when engine total inlet temperature of different conditions are the same or changes small. The model accuracy of compact propulsion system dynamic model, especially the measurable parameters, is improved by online feedback correction. Moreover, the real-time performance of compact propulsion system dynamic model and improved compact propulsion system dynamic model are much better than component level model.

A New Inlet Distortion and Pressure Loss Based Design of an Intake System for Stationary Gas Turbines

2013 ◽  
Author(s):  
Jose Rodriguez ◽  
Stephan Klumpp ◽  
Thomas Biesinger ◽  
James O’Brien ◽  
Tobias Danninger
Keyword(s):  
Gas Turbines ◽  
Inlet System ◽  
Inlet Distortion ◽  
Surge Margin ◽  
Compressor Surge ◽  
Compressor Inlet ◽  
The Face ◽  
Flow Quality ◽  
Inlet Manifold ◽  
Distortion Parameters

This paper presents a new design for a Compressor Inlet Manifold (CIM) for a land-based power generation Gas Turbine (turbine). The CIM is the component of the Inlet System (IS) that is directly connected to the turbine via the Compressor Inlet Case (CIC). The design philosophy is to use low fidelity but fast and automated CFD (Computational Fluid Dynamics) for design iterations and then confirm the design with detailed higher accuracy CFD before proceeding to engine tests. New design features include contouring the wall to minimize areas of flow separation and associated unsteadiness and losses, and improvement of the flow quality into the compressor. The CIM in a land-based turbine acts as a nozzle whereas the inlet of an aircraft acts as a diffuser. The flow also enters the CIM at 90 deg to the engine axis. This leads to a pair of counter rotating vortices at the compressor inlet. Three main sources of flow distortions at the face of the compressor are identified: flow separations at outer walls of the IS and CIM struts and the counter rotating vortices. The higher accuracy CFD analysis including the complete IS, CIM and the first compressor stage, simulates the effect of these distortions on the compressor front stage at design conditions. A range of inlet distortion parameters are used to evaluate the inlet design. The well known DC60 based criterion derived from aircraft engines and other less known but published parameters are able to give an indication of how the compressor surge margin of stationary gas turbines is affected.

scholarly journals Aircraft Engine On-Line Diagnostics Through Dual-Channel Sensor Measurements: Development of a Baseline System

2008 ◽  
Author(s):  
Takahisa Kobayashi ◽  
Donald L. Simon
Keyword(s):  
Fault Detection ◽  
Aircraft Engine ◽  
Fault Detection And Isolation ◽  
Channel Measurements ◽  
Sensor Fault ◽  
Engine Model ◽  
Dual Channel ◽  
Sensor Fault Detection ◽  
Baseline System ◽  
On Line

In this paper, a baseline system which utilizes dual-channel sensor measurements for aircraft engine on-line diagnostics is developed. This system is composed of a linear on-board engine model (LOBEM) and fault detection and isolation (FDI) logic. The LOBEM provides the analytical third channel against which the dual-channel measurements are compared. When the discrepancy among the triplex channels exceeds a tolerance level, the FDI logic determines the cause of the discrepancy. Through this approach, the baseline system achieves the following objectives: 1) anomaly detection, 2) component fault detection, and 3) sensor fault detection and isolation. The performance of the baseline system is evaluated in a simulation environment using faults in sensors and components.

How Crystals Form from a Cloud of Atoms

2011 ◽  
Vol 675-677 ◽  
pp. 3-7
Author(s):  
Peter Häussler ◽  
Martin Stiehler
Keyword(s):  
Structure Formation ◽  
Fundamental Equation ◽  
Structural Features ◽  
Local Order ◽  
Total System ◽  
Angular Momenta ◽  
General Dynamics ◽  
Bloch’S Theorem ◽  
The Given ◽  
First Time

Structure formation, the condensation of a cloud of atoms to a crystal is still not well understood. Disordered sytems (amorphous/liquid) should be in the center of this research, they are the precursors of any crystal. We consider elementary systems, as well as binary, or ternary amorphous alloys, irrespective whether they are metallically, covalently or ionically bonded and describe the process of structure formation in the formal language of thermodynamics but, as far as we know for the first time, by an extended version (general dynamics), based on the complete Gibbs fundamental equation, applied to internal subsystems. Major structural features evolve from global resonances between formerly independent internal subsystems by exchanging momenta and angular momenta, both accompanied by energy. By this they adjust mutually their internal features and create spherical-periodic structural order at medium-range distances. Under the given external constraints the resonances get optimized by selforganization. Global resonances of the type considered have clearly to be distinguished from local resonances between individual ions (described by quantum chemistry) forming local order. The global resonances cause anti-bonding (non-equilibrium) as well as bonding (equilibrium) states of the coupled total system, occupying the latter to form new structurally extended order. The transition to equilibrium creates entropy which itself leaves the system together with energy. At resonance the energetical splitting between the bonding and anti-bonding state is largest, the creation of entropy and the decrease of the total energy therefore, too. The crystal, finally, evolves by additionally optimizing a resonance based on angular momentum, and the additional adjustments of the local resonances to the global ones, theoretically done by applying Bloch’s theorem.

scholarly journals Constitutional Dilemma of Pakistan: 1947 -1956

2018 ◽  
Vol III (I) ◽  
pp. 1-9
Author(s):  
Muhammad Rizwan ◽  
Manzoor Ahmad ◽  
Syed Asif Anwar Bukhari
Keyword(s):  
Human Rights ◽  
Political Leadership ◽  
Deep Insight ◽  
Constitutional Development ◽  
The World ◽  
Refugee Problem ◽  
The Right ◽  
The Given ◽  
The Relationship ◽  
Insight Into

Soon after its creation, Pakistan confronted many issues including refugee problem, scarcity of able political leadership, absence of mutual consensus between both wings of the country and confusing nature of the relationship between Islam and state etc. took almost nine years to frame the permanent constitution for Pakistan. Constitution, the basic document of a state, determines the shape of its laws, structure of governance and system of rights and duties. The effectiveness of a constitution is judged by its practicability in the given area where it is enforced by the state machinery. Although, all civilized states of the world do possess a constitution, yet a good constitution is one which must protect the basic human rights by ensuring the independence of judiciary. Due to countless hurdles at the beginning of its journey, Pakistan’s constitutional development in the right direction could not take place. The main objective of the present study is to provide deep insight into the events and factors causing a delay in the constitution-making for the newly created state of Pakistan. The various events which took place from 1947 to 1956 have been analyzed in a subtle way.

scholarly journals Scientific methods of public administration in migration research

2020 ◽  
Vol 68 (2) ◽  
pp. 109-122
Author(s):  
András László Szabó
Keyword(s):  
Public Administration ◽  
Research Methods ◽  
Methodological Approach ◽  
Point Of View ◽  
Scientific Methods ◽  
Migration Research ◽  
Independent Field ◽  
The Subject ◽  
The Given ◽  
Insight Into

In my study, I list the directions of migration research, all from the point of view of public administration science. The emergence of migration research as an independent field is necessitated by the growth of migration. Researchers are researching the phenomenon of migration from their own field. Public administration uses a multidisciplinary, i.e. methodological approach of several disciplines, all of which is determined by the knowledge and nature of the subject of the given research. In the following, I review and evaluate the methodological directions of the research, which can provide an answer to a segment of the phenomenon of migration. The study gives an insight into research methods for migration research. It is not intended to present specific examples and procedures. At the end of the study, in possible directions, beyond the science of public administration, I list the organizations and faculties that are able to use the methodology of migration research.

UNDERSTANDING BLOGGERS POSTING ABOUT POP CULTURE: LINGUAPRAGMATICS OF «UNPOPULAR OPINION» IN THE ENGLISH INTERNET-DISCOURSE

2021 ◽  
Author(s):  
A.V. Kukovskaya
Keyword(s):  
Discourse Analysis ◽  
Cognitive Processes ◽  
Pop Culture ◽  
Computer Mediated ◽  
The Subject ◽  
The Given ◽  
Insight Into ◽  
Blog Posts ◽  
Subcultural Community

The paper explores communication within the English blogosphere in which the discourse manifests itself in blog posts, devoted, in particular, to reactions to a variety of pop-culture works. These posts are characterized by specific linguapragmatics. The article examines the language and the discourse of bloggers from the standpoint of the Linguistic Creativity approach, which may help to have an in-depth insight into the mechanisms of cognitive processes. The topicality of this topic is justified by the interest that modern linguists have in text studies, discourse analysis and computer-mediated Internet-discourse. The novelty of the article lies in the fact that the given discourse and the linguapragmatics of the posts in question in the English blogosphere have not so far received the attention they deserve and should be the subject of more research and analysis. The paper supplies relevant conclusions made on the basis of the empiric material. The research demonstrates that within the English Internet-discourse of bloggers, who interpret modern pop culture and can be considered a subcultural community, among other types of posts there can be singled out the so-called “unpopular opinion”, that boasts a number of linguapragmatic peculiarities coinciding with the communicative goals of bloggers. Decoding such posts may be a challenge and we, among other things, want to draw researchers’ attention to the “language of bloggers” and its study.

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