Centrifugal Compressor Modifications and Their Effect on High-Frequency Pipe Wall Vibration

1998 ◽  
Vol 120 (3) ◽  
pp. 276-282 ◽  
Author(s):  
R. W. Motriuk ◽  
D. P. Harvey
Keyword(s):  
High Frequency ◽  
Pipe Wall ◽  
Centrifugal Compressors ◽  
Partial Removal ◽  
Vibration Attenuation ◽  
Internal Component ◽  
Compressor Performance ◽  
And Performance ◽  
Component Failures ◽  
Fatigue Failures

High-frequency pulsation generated by centrifugal compressors, with pressure wavelengths much smaller than the attached pipe diameter, can cause fatigue failures of the compressor internals, impair compressor performance, and damage the attached compressor piping. There are numerous sources producing pulsation in centrifugal compressors. Some of them are discussed in literature at large (Japikse, 1995; Niese, 1976). NGTL has experienced extreme high-frequency discharge pulsation and pipe wall vibration on many of its radial inlet high-flow centrifugal gas compressor facilities. These pulsations led to several piping attachment failures and compressor internal component failures while the compressor operated within the design envelope. This paper considers severe pulsation conditions at an NGTL compression facility which resulted in unacceptable piping vibration. Significant vibration attenuation was achieved by modifying the compressor (pulsation source) through removal of the diffuser vanes and partial removal of the inlet guide vanes (IGV). Direct comparison of the changes in vibration, pulsation, and performance are made for each of the modifications. The vibration problem, probable causes, options available to address the problem, and the results of implementation are reviewed. The effects of diffuser vane removal on discharge pipe wall vibration as well as changes in compressor performance are described.

Effects of Asymmetric Radial Clearance on Performance of a Centrifugal Compressor

2017 ◽  
Vol 140 (5) ◽  
Author(s):  
Cheng Xu ◽  
Ryoichi S. Amano
Keyword(s):  
Pressure Ratio ◽  
Industrial Applications ◽  
Radial Clearance ◽  
Centrifugal Compressors ◽  
Numerical Studies ◽  
Compressor Design ◽  
Compressor Performance ◽  
Manufacturing Tolerances ◽  
And Performance ◽  
Design Pressure

The centrifugal compressors are widely used in industrial applications. The design, manufacturing, and installation are all critical for the compressor performance. Many studies have been carried out in the past to optimize the compressor performance during compressor design. The manufacturing tolerances and installation errors can cause the performance drop. There are many compressor performance distortions that are not fully understood due to manufacturing and facilities. In this paper, an asymmetrical radial clearance of the impeller due to manufacturing and installation is studied in detail for the performance impacts. The numerical studies and experiments indicated that the asymmetric radial clearance impacts the compressor flow field structure and performance. Experimental results suggested that the manufacturing and installation cause asymmetric radial clearance which decreased the compressor performance in whole operating range. The numerical analysis demonstrated that the impeller asymmetric clearance impacts performance near the design pressure ratio more than other pressure ratios. The numerical studies showed that the maximum clearance location of asymmetric clearance might impact the compressor performance. The proper asymmetricity of diffuser verse the volute may benefit the compressor performance. The excellent compressor performances for centrifugal compressors especially for small centrifugal compressors not only need to have a good aerodynamic design but also need to control manufacturing and installation carefully.

Size and Performance Tradeoffs in Micro-Inductors for High Frequency DC-DC Conversion

2009 ◽  
Vol 45 (10) ◽  
pp. 4234-4237 ◽  
Author(s):  
R. Meere ◽  
T. O'Donnell ◽  
N. Wang ◽  
N. Achotte ◽  
S. Kulkarni ◽  
...  
Keyword(s):  
High Frequency ◽  
And Performance

Fabrication and performance of Fe-based magnetic thin film inductor for high-frequency application

2008 ◽  
Vol 320 (20) ◽  
pp. e963-e966 ◽  
Author(s):  
Yong Zhou ◽  
Zhi-Min Zhou ◽  
Ying Cao ◽  
Xiao-Yu Gao ◽  
Wen Ding
Keyword(s):  
Thin Film ◽  
High Frequency ◽  
Magnetic Thin Film ◽  
High Frequency Application ◽  
And Performance

scholarly journals Variability and Performance of Short to Long-Range Single Baseline RTK GNSS Positioning in Indonesia

2019 ◽  
Vol 94 ◽  
pp. 01012 ◽  
Author(s):  
Irwan Gumilar ◽  
Brian Bramanto ◽  
Fuad F. Rahman ◽  
I Made D. A. Hermawan
Keyword(s):  
Long Range ◽  
High Frequency ◽  
Carrier Phase ◽  
Satellite System ◽  
High Accuracy ◽  
Gnss Positioning ◽  
And Performance ◽  
Gnss Network ◽  
Single Baseline ◽  
Global Navigation Satellite

As the modernized Global Navigation Satellite System (GNSS) method, Real Time Kinematic (RTK) ensures high accuracy of position (within several centimeters). This method uses Ultra High Frequency (UHF) radio to transmit the correction data, however, due to gain and power issues, Networked Transport of RTCM via Internet Protocol (RTCM) is used to transmit the correction data for a longer baseline. This Research aims to investigate the performance of short to long-range single baseline RTK GNSS (Up to 80 KM) by applying modified LAMBDA method to resolve the ambiguity in carrier phase. The RTK solution then compared with the differential GNSS network solution. The results indicate that the differences are within RTK accuracy up to 80 km are several centimeter for horizontal solution and three times higher for vertical solution.

An Overview of Aircraft Accident Investigation and Component Failures

2021 ◽  
pp. 778-786
Author(s):  
Ellen E. Wright ◽  
Suzanne F. Uchneat
Keyword(s):  
Case Studies ◽  
Environmental Effects ◽  
System Level ◽  
Accident Investigation ◽  
Materials Engineering ◽  
Aircraft Component ◽  
And Performance ◽  
Aircraft Accident ◽  
Component Failures ◽  
Structure Properties

Abstract This article focuses on failure analyses of aircraft components from a metallurgical and materials engineering standpoint, which considers the interdependence of processing, structure, properties, and performance of materials. It discusses methodologies for conducting aircraft investigations and inspections and emphasizes cases where metallurgical or materials contributions were causal to an accident event. The article highlights how the failure of a component or system can affect the associated systems and the overall aircraft. The case studies in this article provide examples of aircraft component and system-level failures that resulted from various factors, including operational stresses, environmental effects, improper maintenance/inspection/repair, construction and installation issues, manufacturing issues, and inadequate design.

scholarly journals Design and Performance of a High‐Frequency Electrostatic Speaker

1955 ◽  
Vol 27 (1) ◽  
pp. 211-211
Author(s):  
Lloyd Bobb ◽  
R. B. Goldman ◽  
R. W. Roof
Keyword(s):  
High Frequency ◽  
And Performance

Sexual behavior and sexual problems among patients with severe chronic psychoses

2003 ◽  
Vol 18 (2) ◽  
pp. 70-76 ◽  
Author(s):  
Michele Raja ◽  
Antonella Azzoni
Keyword(s):  
Sexual Behavior ◽  
High Frequency ◽  
Ad Hoc ◽  
Psychiatric Patients ◽  
Female Gender ◽  
Sexual Performance ◽  
Negative Effects ◽  
Sexually Transmitted ◽  
And Performance ◽  
The Impact

AbstractThe aim of the present study was to investigate sexual behavior in a population of psychiatric patients affected by schizophrenia, schizoaffective disorder or bipolar disorder by means of an ad hoc questionnaire designed to explore the three phases of the sexual response: desire (or interest), arousal, and performance. The study assessed patients’ attitude toward sexuality, several aspects of their sexual behavior, including patients’ awareness of the risk of sexually transmitted diseases (STD), contraceptive strategy preferred by patients, and sexual effects of psychotropic medication. Patients reported a high frequency of sexual dysfunction, in particular, hyposexuality. Schizophrenia diagnosis and female gender were associated with lower levels of sexual performance. The impact of psychotropic drugs on patients’ sexuality was significant, with both positive and negative effects. Although 65.8% of patients reported to be concerned about the risk of contracting infections during sexual intercourse, most of them engaged in sexual behavior at high risk for acquisition and transmission of STD. Patients’ compliance with contraceptive measures was poor.

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