NASA Logo

NTRS

NTRS - NASA Technical Reports Server

Back to Results
In-Service Monitoring of Steam Pipe Systems at High TemperaturesAn effective, in-service health monitoring system is needed to track water condensation in real time through the walls of steam pipes. The system is required to measure the height of the condensed water from outside the pipe, while operating at temperatures that are as high as 250 C. The system needs to account for the effects of water flow and cavitation. In addition, it is desired that the system does not require perforating the pipes and thereby reducing the structural integrity. Generally, steam pipes are used as part of the district heating system carrying steam from central power stations under the streets to heat, cool, or supply power to high-rise buildings and businesses. This system uses ultrasonic waves in pulse-echo and acquires reflected signal data. Via autocorrelation, it determines the water height while eliminating the effect of noise and multiple reflections from the wall of the pipe. The system performs nondestructive monitoring through the walls of steam pipes, and automatically measures the height of condensed water while operating at the high-temperature conditions of 250 C. For this purpose, the ultrasonic pulse-echo method is used where the time-of-flight of the wave reflections inside the water are measured, and it is multiplied by the wave velocity to determine the height. The pulse-echo test consists of emitting ultrasonic wave pulses from a piezoelectric transducer and receiving the reflections from the top and bottom of the condensed water. A single transducer is used as a transmitter as well as the receiver of the ultrasonic waves. To obtain high resolution, a broadband transducer is used and the frequency can be in the range of 2.25 to 10 MHz, providing sharp pulses in the time domain allowing for higher resolution in identifying the individual reflections.
Document ID
20120000440
Acquisition Source
Jet Propulsion Laboratory
Document Type
Other - NASA Tech Brief
Authors
Bar-Cohen, Yoseph
(California Inst. of Tech. Pasadena, CA, United States)
Lih, Shyh-Shiuh
(California Inst. of Tech. Pasadena, CA, United States)
Badescu, Mircea
(California Inst. of Tech. Pasadena, CA, United States)
Bao, Xiaoqi
(California Inst. of Tech. Pasadena, CA, United States)
Sherrit, Stewart
(California Inst. of Tech. Pasadena, CA, United States)
Scott, James S.
(California Inst. of Tech. Pasadena, CA, United States)
Blosiu, Julian O.
(California Inst. of Tech. Pasadena, CA, United States)
Widholm, Scott E.
(California Inst. of Tech. Pasadena, CA, United States)
Date Acquired
August 25, 2013
Publication Date
September 1, 2011
Publication Information
Publication: NASA Tech Briefs, September 2011
Subject Category
Man/System Technology And Life Support
Report/Patent Number
NPO-47518
Distribution Limits
Public
Copyright
Public Use Permitted.
No Preview Available