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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Journal of nondestructive evaluation 3 (1982), S. 99-109 
    ISSN: 1573-4862
    Keywords: thermography ; infrared scanning ; calibration ; inverse problems ; cavity detection ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An approach for treating nondestructive testing as the solution of inverse problems in mathematical physics has been used for the detection of cavities. The approach is developed based on the use of an additional boundary condition of scanned temperature on the surface to solve for the cavity geometry. For the present study, the condition at the cavity side is taken to be that of a specified temperature, and the experiment is carried out to meet this condition. Two specimens are tested in this paper, a plane slab and a rectangular prism. In both bodies the cavity is rectangular in shape. For the testing of the plane slab, the method is able to detect the cavity wall with high accuracy, whereas the cavity depth error is larger (6%). The detection of the cavity position in the rectangular prism has an error ranging from −9.7 to 7.7%. Errors in the experiment are attributed to the uncertainties in the measurements of temperature and the Biot number. The former is read off from the analog data output of the infrared scanner. The latter is not measured separately, but is computed from the scanned data and thus becomes a portion of the total nondestructive testing output. A final note is also made in this paper to relate how the presented method can be used in actual practice.
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Journal of nondestructive evaluation 4 (1984), S. 133-140 
    ISSN: 1573-4862
    Keywords: Thermography ; infrared scanning ; calibration ; inverse problem ; cavity detection ; NDE
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Mathematics
    Notes: Abstract An inverse problem technique has been developed for detecting irregular cavities in circular cylinders. In this method, the cavity is considered a part of the unknown geometry of the investigated system, and the evaluated temperature is used to locate this geometry. An auxiliary problem is introduced in the solution of this problem; and in the solution, the cavity wall is located by forcing the temperature to satisfy the condition imposed at the cavity. The new methodology is validated by an experiment presented in this paper, and the test results indicate that this method is highly successful in locating cavities. The accuracy of the method is closely related to the accuracy of the temperature that can be measured at the surface. A small error in the surface temperature results in a slight cavity error for deep cavities, while a shallow cavity is not severely affected by a surface temperature error. This method is particularly attractive in detecting shallow cavities in nondestructive evaluation.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 15 (1992), S. 865-881 
    ISSN: 0271-2091
    Keywords: Gas turbine combustors ; CFD ; Emissions ; Airblast atomizers ; Dilution jet mixing ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: A numerical study was performed to investigate chemically reactive flows with sprays inside a staged turbine combustor (STC) using a modified version of the KIVA-II code. This STC consists of a fuel nozzle (FN), a rich-burn (RB) zone, a converging connecting pipe, a quick-quench (QQ) zone, a diverging connecting pipe and a lean-combustion (LC) zone. From the computational viewpoint, it is more efficient to split the STC into two subsystems, called FN/RB zone and QQ/LC zones, and the numerical solutions were obtained separately for each subsystem. This paper addresses the numerical results of the STC which is equipped with an advanced airblast fuel nozzle. The airblast nozzle has two fuel injection passages and four air flow passages. The input conditions used in this study were chosen similar to those encountered in advanced combustion systems. Preliminary results generated illustrate some of the major features of the flow and temperature fields inside the STC. Velocity, temperature and some critical species information inside the FN/RB zone are given. Formation of the co- and counter-rotating bulk flow and the sandwiched-ring-shaped temperature field, typical of the confined inclined jet-in-cross-flow, can be seen clearly in the QQ/LC zones. The calculations of the mass-weighted standard deviation and the pattern factor of temperature revealed that the mixing performance of the STC is very promising. The temperature of the fluid leaving the LC zone is very uniform. Prediction of the NOx emission shows that there is no excessive thermal NOx produced in the QQ/LC zones for the case studied. From the results obtained so far, it appears that the modified KIVA-II code can be used to guide the low-emission combustion experiments.
    Additional Material: 15 Ill.
    Type of Medium: Electronic Resource
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