Smoothing strategies for surface temperatures measured during vigorous transient boiling

Conference · Mon Jan 01 00:00:00 EST 1990

OSTI ID:6781935

Park, J E; Chu, W; Ludtka, G M

A vertically oriented hollow nickel cylinder (0.15-m dia, 0.3-m height, 0.095-m wall thickness) has been quenched in cold (22 {degree}C) water from an initial temperature of 810{degree}C. During the quench, the output from surface-mounted intrinsic thermocouples was digitized and recorded at intervals of 0.004 s over a test period of 40 s. The output from one of these thermocouples is examined in detail. A procedure for smoothing and interpreting the output is developed. The raw thermocouple signals exhibit three distinct regimes, stable film boiling (surface temperatures of above 400{degree}C), unstable film boiling (400{degree} to 120-140{degree}C), and nucleate boiling. In the first and second regimes, the data show fluctuations of {plus minus}50{degree}C that are attributed to formation and collapse of bubbles on the vertical surface of the cylinder. Because the measurements are ultimately to be used to predict surface heat fluxes, the high-frequency fluctuations must be removed or averaged without destroying the transient character of the cooling curve. Three strategies are discussed: (1) Beck's Second Inverse Heat Conduction method, (2) a moving window with a linear least-mean-squares (LMS) fit to replace each point in turn, and (3) Fourier series with the highest frequencies deleted from the spectrum before reconstructing the signals. The experiments are summarized, the raw data are analyzed, the methods are explained, and results using each of the methods are presented and discussed. 13 refs., 10 figs.

• Research Organization: Oak Ridge Gaseous Diffusion Plant (K-25), Oak Ridge, TN (United States)
• Sponsoring Organization: DOE/DP
• DOE Contract Number: AC05-84OT21400
• OSTI ID: 6781935
• Report Number(s): K/CSD/INF-89/31/R1; CONF-900619-6; ON: DE90013705
• Resource Relation: Conference: 5. AIAA/ASME thermal physics and heat transfer conference, Seattle, WA (USA), 18-20 Jun 1990
• Country of Publication: United States
• Language: English

Related Subjects

42 ENGINEERING
36 MATERIALS SCIENCE
99 GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
NICKEL
PHYSICAL PROPERTIES
SURFACE PROPERTIES
SURFACES
HEAT TRANSFER
ALGORITHMS
COMPARATIVE EVALUATIONS
DATA ACQUISITION SYSTEMS
DATA ANALYSIS
DATA PROCESSING
FOURIER ANALYSIS
FREQUENCY ANALYSIS
HEAT FLUX
NOISE
OSCILLATIONS
QUENCHING
STABILITY
STRESSES
TEMPERATURE MEASUREMENT
THERMOCOUPLES
TRANSIENTS
VAPORS
ELEMENTS
ENERGY TRANSFER
FLUIDS
GASES
MATHEMATICAL LOGIC
MEASURING INSTRUMENTS
METALS
PROCESSING
TRANSITION ELEMENTS
420400* - Engineering- Heat Transfer & Fluid Flow
360104 - Metals & Alloys- Physical Properties
360103 - Metals & Alloys- Mechanical Properties
990200 - Mathematics & Computers