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Title: In situ heat exchanger tube fouling thickness measurements using ultrasonics. Final report on a laboratory feasibility study

Abstract

The growth of fouling layers on heat exchanger surfaces and the corrosion of heat exchanger materials exposed to seawater have been recognized since the beginning of OTEC research as basic problems which could render the concept uneconomical. Consequently, a significant effort has been directed toward predicting, measuring, identifying, explaining and solving potential biofouling and corrosion phenomena. To address this problem, the feasibility of establishing a practical microacoustic technique to measure fouling film thickness in situ on typical OTEC heat exchanger tasks was studied. Seven techniques were studied for this application, including velocity measurements, acoustic diffraction, acoustic interferometer, Doppler flow velocity, pulse echo, critical angle, and surface (shear) wave effects. Of these, the latter five were laboratory tested using conventional microacoustic system components in various configuratons. Only the pulse echo technique yielded promising results. On fouled aluminum plates, thin film layers of 40 ..mu..m and greater were measured using a focused 30 MHz ceramic transducer operated at 25 MHz; this represents a resolution of about 2/3 wavelength. Measurements made on the inside of fouled 1'' aluminum pipes yielded film thicknesses of 75 to 125 ..mu..m. The thinnest layer resolved was approximately 1-1/4 wavelength. The resolution of slime layer thicknesses in themore » magnitudes of OTEC interest (5 to 30 ..mu..m) using pulse echo microacoustics will require transducer development. In particular, a higher operating frequency (150 to 200 MHz) and advanced material construction is recommended for further research.« less

Authors:
;
Publication Date:
Research Org.:
Army Nuclear Agency, Fort Bliss, TX (USA); Tracor Marine, Port Everglades, FL (USA)
Sponsoring Org.:
USDOE
OSTI Identifier:
6720773
Report Number(s):
ANL/OTEC-BCM-014
DOE Contract Number:  
W-31-109-ENG-38
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
14 SOLAR ENERGY; HEAT EXCHANGERS; DEPOSITS; OCEAN THERMAL ENERGY CONVERSION; ALUMINIUM; BACTERIA; BIOLOGICAL FOULING; CORROSION; FOULING; HEAT TRANSFER; INTERFEROMETRY; LAYERS; MEASURING METHODS; PIPES; SEAWATER; THICKNESS; TUBES; ULTRASONIC TESTING; ACOUSTIC TESTING; CHEMICAL REACTIONS; CONVERSION; DIMENSIONS; ELEMENTS; ENERGY CONVERSION; ENERGY TRANSFER; HYDROGEN COMPOUNDS; MATERIALS TESTING; METALS; MICROORGANISMS; NONDESTRUCTIVE TESTING; OXYGEN COMPOUNDS; SOLAR ENERGY CONVERSION; TESTING; WATER; 140800* - Solar Energy- Ocean Energy Systems

Citation Formats

Hirshman, J, and Munier, R S.C. In situ heat exchanger tube fouling thickness measurements using ultrasonics. Final report on a laboratory feasibility study. United States: N. p., 1980. Web. doi:10.2172/6720773.
Hirshman, J, & Munier, R S.C. In situ heat exchanger tube fouling thickness measurements using ultrasonics. Final report on a laboratory feasibility study. United States. doi:10.2172/6720773.
Hirshman, J, and Munier, R S.C. Mon . "In situ heat exchanger tube fouling thickness measurements using ultrasonics. Final report on a laboratory feasibility study". United States. doi:10.2172/6720773. https://www.osti.gov/servlets/purl/6720773.
@article{osti_6720773,
title = {In situ heat exchanger tube fouling thickness measurements using ultrasonics. Final report on a laboratory feasibility study},
author = {Hirshman, J and Munier, R S.C.},
abstractNote = {The growth of fouling layers on heat exchanger surfaces and the corrosion of heat exchanger materials exposed to seawater have been recognized since the beginning of OTEC research as basic problems which could render the concept uneconomical. Consequently, a significant effort has been directed toward predicting, measuring, identifying, explaining and solving potential biofouling and corrosion phenomena. To address this problem, the feasibility of establishing a practical microacoustic technique to measure fouling film thickness in situ on typical OTEC heat exchanger tasks was studied. Seven techniques were studied for this application, including velocity measurements, acoustic diffraction, acoustic interferometer, Doppler flow velocity, pulse echo, critical angle, and surface (shear) wave effects. Of these, the latter five were laboratory tested using conventional microacoustic system components in various configuratons. Only the pulse echo technique yielded promising results. On fouled aluminum plates, thin film layers of 40 ..mu..m and greater were measured using a focused 30 MHz ceramic transducer operated at 25 MHz; this represents a resolution of about 2/3 wavelength. Measurements made on the inside of fouled 1'' aluminum pipes yielded film thicknesses of 75 to 125 ..mu..m. The thinnest layer resolved was approximately 1-1/4 wavelength. The resolution of slime layer thicknesses in the magnitudes of OTEC interest (5 to 30 ..mu..m) using pulse echo microacoustics will require transducer development. In particular, a higher operating frequency (150 to 200 MHz) and advanced material construction is recommended for further research.},
doi = {10.2172/6720773},
journal = {},
number = ,
volume = ,
place = {United States},
year = {1980},
month = {9}
}