ON THE MEASUREMENT OF THE DYNAMIC PROPERTIES OF THE STEAM VOID FRACTION IN BOILING WATER CHANNELS

Technical Report · Thu Jun 01 04:00:00 EDT 1961

DOI:https://doi.org/10.2172/4840752· OSTI ID:4840752

Eurola, A. T.

The problem of determining the dynamic properties of the steam void fraction undergoing random variations at a particular location in a boiling channel was studied. Emphasis was placed on a gamma attenuation method and on a method employing sensitive flowmeters at suitable locations of the channel. The dynamic properties of interest were the autocorrelation function and the power density spectrum of the variations. Equations were derived for computing the desired quantities on the basis of gamma records obtained during actual boiling experiments and from runs with empty and full, nonboiling channels. The equations consider the statistical variations of the gamma source and detector. A procedure was outlined for estimating the measurement effort to obtdin a predetermined accuracy. Two models were developed to correlate the variations of flow with fluctuations of the steam void. Both models were based on the mass continuity equation for a two-phase fluid. The simpler model leads to a first- order, linear differential equation with randomly varying coefficients. The desired quantities can be computed from the equation. The second model leads to a linear integral equation of the third kind. This equation relates the power density spectrum of the void fraction with the spectra of the water velocities. A frequency range from zero to five cycles per second was investigated. A comparison of the results obtained with the gamma-ray and velocity methods on a 42-atm heat-transfer loop indicated that neither model satisfactorily relates the velocity variations with the steam void variations over the entire range of frequencies studied. However, if the steam transit time is about 0.1 sec and the frequency range of interest less than one cycle per second, both models are useful and have approximately the same accuracy. At frequencies greater than one cycle per three decibels for a 0.1-sec steam transit time. The second model gives slightly better results than the first. The accuracy of the models increases with decreasing steam transit time. (auth)

• Research Organization: Argonne National Lab., Ill.
• DOE Contract Number: W-31109-ENG-38
• NSA Number: NSA-15-029348
• OSTI ID: 4840752
• Report Number(s): ANL-6369
• Country of Publication: United States
• Language: English

Related Subjects

BOILING
COMPUTERS
COOLANT LOOPS
DIFFERENTIAL EQUATIONS
ENGINEERING AND EQUIPMENT
EQUATIONS
EVAPORATION
FLOW MODELS
FLOWMETERS
FLUID FLOW
FREQUENCY
GAMMA RADIATION
MATHEMATICS
MEASURED VALUES
MECHANICS
PERFORMANCE
RADIATION DETECTORS
RECORDING SYSTEMS
SENSITIVITY
STANDARDS
STATISTICS
STEAM
STEAM QUALITY
THERMAL DIFFUSION
TUBES
VARIATIONS
VELOCITY
WATER