Characteristics of turbine-type flowmeters in two sizes and with various types of bearings are presented. Calibration procedures of instruments are described. Accuracies obtainable under various conditions are analyzed

Hobart, H. F.

Minkin, H. L.

Warshawsky, I.

English

NASA Technical Reports Server

July 1972	 B72-10331 
S	 NASA TECH BRIEF 
Lewis Research Center	
_4V 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage 
commercial application. Tech Briefs are available on a subscription basis from the National Technical Information 
Service, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Office, NASA, Code KT, Washington, D.C. 20546. 
Small Turbine-Type Flowmeters for Liquid Hydrogen 
Statistical data have been obtained on the repro-
ducibility and linearity of turbine-type flowmeters in 2.5 
and 4 cm sizes and with various types of bearings. The 
results indicate design principles, installation practices, 
and inspection procedures that are conducive to re-
liability. Comparisons are made between calibrations 
obtained with liquid hydrogen, with water, and with 
high-pressure nitrogen gas. Actual calibration in liquid 
hydrogen is required to identify meters of good quality 
(calibration reproducibility with less than 0.3 percent 
probable error) and to establish the mean calibration 
curve with minimum error. 
The results showed that designs operating at fluid 
velocities up to 30 m/sec can yield a calibration factor 
that is constant to 0.5 percent over a 10:1 flow range. 
The experiments also indicated that it is now possible to 
obtain meters whose calibration factor is reproducible to 
a probable error on the order of 0.1 percent at full scale. 
The worst value of probable error was only 0.2 percent. 
Curves were obtained from which probable error can be 
determined at velocities lower than that at full scale. 
Water calibrations are unlikely to yield values of calibra-
tion factor with values of probable error as small as those 
derivable from a liquid-hydrogen calibration. Small 
blade-tip clearance, which is feasible in a clean fluid like 
hydrogen, appears to improve meter performance. 
Observations on reliability suggest that a meter that 
has passed preliminary inspection should be run in for a 
few hours at a variety of positive and negative velocities, 
and then calibrated at least four times preferably over an 
interval of several days. If all calibrations consistently
show a probable error of a single observation of less than 
0.3 percent . of the calibration factor, the meter is usable. 
Good meters showed a probable error on the same order 
as that of the calibration facility. The cleanliness, fit, and 
alignment of bearings is considered most important. This 
fact should dominate the packaging, storage, repair, and 
handling of any meter. 
Notes: 
1. The following documentation may be obtained from: 
National Technical Information Service 
Springfield, Virginia 22151 
Single document price $3.00 
(or microfiche $0.95) 
Reference: NASA TM-X-52984 (N71-19703), 
Small Turbine-Type Flowmeters for Liquid 
Hydrogen 
Technical questions may be directed to: 
Technology Utilization Officer 
Lewis Research Center 
21000 Brookpark Road 
Cleveland, Ohio 44135 
Reference 1372-10331 
Patent status: 
No patent action is contemplated by NASA. 
Source: Isidore Warshawsky, Howard F. Hobart, and

Herbert L. Minkin
Lewis Research Center

(LEW-1 1535) 
Category 06 
Thisdocumentwas prepared underthe sponsorship of the National
	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States
	 will be free from privately owned rights.
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Small turbing-type flowmeters for liquid hydrogen

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