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Title: Critical speed measurements in the Tevatron cold compressors

Abstract

The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high energy operations. Nominal operating range for these compressors is 43,000 to 85,000 rpm. Past foil bearing failures prompted investigation to determine if critical speeds for operating compressors fall within operating range. Data acquisition hardware and software settings will be discussed for measuring liftoff, first critical and second critical speeds. Several tests provided comparisons between an optical displacement probe and accelerometer measurements. Vibration data and analysis of the 20 Tevatron ring cold compressors will be presented.

Authors:
; ; ; ;
Publication Date:
Research Org.:
Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
897189
Report Number(s):
FERMILAB-CONF-05-636-AD
TRN: US0701252
DOE Contract Number:
AC02-07CH11359
Resource Type:
Conference
Resource Relation:
Journal Name: AIP Conf.Proc.823:1392-1398,2006; Conference: Prepared for 2005 Cryogenic Engineering Conference and International Cryogenic Materials Conference (CEC-ICMC 2005), Keystone, Colorado, 29 Aug - 2 Sep 2005
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 47 OTHER INSTRUMENTATION; ACCELEROMETERS; BEARINGS; COMPRESSORS; CRYOGENICS; DATA ACQUISITION; FERMILAB TEVATRON; PROBES; VELOCITY; Accelerators

Citation Formats

DeGraff, B., Bossert, R., Martinez, A., Soyars, W.M., and /Fermilab. Critical speed measurements in the Tevatron cold compressors. United States: N. p., 2006. Web.
DeGraff, B., Bossert, R., Martinez, A., Soyars, W.M., & /Fermilab. Critical speed measurements in the Tevatron cold compressors. United States.
DeGraff, B., Bossert, R., Martinez, A., Soyars, W.M., and /Fermilab. Sun . "Critical speed measurements in the Tevatron cold compressors". United States. doi:. https://www.osti.gov/servlets/purl/897189.
@article{osti_897189,
title = {Critical speed measurements in the Tevatron cold compressors},
author = {DeGraff, B. and Bossert, R. and Martinez, A. and Soyars, W.M. and /Fermilab},
abstractNote = {The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high energy operations. Nominal operating range for these compressors is 43,000 to 85,000 rpm. Past foil bearing failures prompted investigation to determine if critical speeds for operating compressors fall within operating range. Data acquisition hardware and software settings will be discussed for measuring liftoff, first critical and second critical speeds. Several tests provided comparisons between an optical displacement probe and accelerometer measurements. Vibration data and analysis of the 20 Tevatron ring cold compressors will be presented.},
doi = {},
journal = {AIP Conf.Proc.823:1392-1398,2006},
number = ,
volume = ,
place = {United States},
year = {Sun Jan 01 00:00:00 EST 2006},
month = {Sun Jan 01 00:00:00 EST 2006}
}

Conference:
Other availability
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  • This paper discusses performance of a final prototype cold compressor and the specification and purchase of production units for the Fermilab Tevatron. Cold helium vapor compressors will be added to the satellite refrigeration system in order to operate the accelerator at higher beam energy. A final machine specification emerged from extensive prototype testing in actual Tevatron refrigerators. These tests resulted in a decision to use high speed turbomachines instead of reciprocating units. The choice was based on performance, size, maintenance requirements, and reliability. IHI Co., Ltd. was selected to provide a final prototype centrifugal machine. Thermodynamic as well as mechanicalmore » performance of this unit is described. Satisfactory performance of the final prototype enabled the author to solicit bids for the full 27 unit order. Cryostat details differ from the prototype although the performance specification is identical. IHI received the order and has delivered all machines. A brief description of the design, purchase, and acceptance testing of these units is given.« less
  • The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/sec of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/sec. Operating speeds are between 40 and 95 krpm, with a speed of 80 krpm at the design point. Different heat loads and magnet quench performance of each of the twenty-four satellite refrigerators dictates different process pressure and flow rates of the cold compressors. Reducing the process flow rate canmore » cause the centrifugal cold compressor to stop pumping and subsequently surge. Tests have been conducted at the Cryogenic Test Facility at Fermilab to map the pressure field and appropriate efficiency of the IHI hydrodynamic cold compressor. The information allows tuning of each of the twenty-four Tevatron satellite refrigerators to avoid cold compressor operation near the surge and choke lines. A new impeller has also been tested. The Tevatron cold compressor pressure field and efficiency data with the new impeller are presented in this paper.« less
  • The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, made by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations [1]. The compressor is designed to pump 60 g/s of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/s and operating speeds between 40 and 95 krpm. Since initial commissioning in 1993, Tevatron transient conditions such as quench recovery have led to multiple-location machine trips as a result of the cold compressors entering the surge regime. Historically, compressors operating at lower inlet pressures and higher speeds have beenmore » especially susceptible to these machine trips and it was not uncommon to have multiple compressor trips during large multiple-house quenches. In order to cope with these events and limit accelerator down time, surge recovery techniques have been implemented in an attempt to prevent the compressors from tripping once the machine entered this surge regime. This paper discusses the different methods of surge recovery that have been employed. Data from tests performed at the Cryogenic Test Facility at Fermilab as well as actual Tevatron operational data were utilized. In order to aid in the determination of the surge region, a full mapping study was undertaken to characterize the entire pressure field of the cold compressor. These techniques were then implemented and tested at several locations in the Tevatron with some success.« less
  • The Fermilab Tevatron cryogenic system utilizes high-speed centrifugal cold compressors, manufactured by Ishikawajima-Harima Heavy Industries Co. Ltd. (IHI), for high-energy operations. The compressor is designed to pump 60 g/sec of 3.6 K saturated helium vapor at a pressure ratio of 2.8, with an off-design range of 40 to 70 g/sec. Operating speeds are between 40,000 and 95,000 rpm, with a speed of 80,000 rpm at the design point. Different heat loads and magnet quench performance of each of the twenty-four satellite refrigerators dictates different process pressure and flow rates of the cold compressors. Reducing the process flow rate can causemore » the centrifugal cold compressor to stop pumping and subsequently surge. Tests have been conducted at the Cryogenic Test Facility at Fermilab to map the pressure field and appropriate efficiency of the IHI hydrodynamic cold compressor. The information allows tuning of each of the twenty-four Tevatron satellite refrigerators to avoid cold compressor operation near the surge and choke lines. A new impeller has also been tested. The Tevatron cold compressor pressure field and efficiency data with the new impeller are presented in this paper.« less