Babcock & Wilcox

About: Babcock & Wilcox is a based out in . It is known for research contribution in the topics: Boiler (power generation) & Flue gas. The organization has 3085 authors who have published 3732 publications receiving 39437 citations.

Ultrasonic testing of materials

Abstract: An ultrasonic apparatus for testing a material comprises an oscillator (10) which generates a selected frequency in the ultrasonic range. A transducer (1) is connected to the oscillator (10) for applying an ultrasonic signal to the material and for receiving an echo signal back from the material. A phase detector (5) receives the echo signal and an in-phase oscillator signal to generate a first display signal, and a phase detector (6) receives a quadrature signal (90° out of phase from the oscillator signal) and the echo signal to generate a second display signal. The first and second display signals are utilised in a visual display, such as a cathode ray tube (8), to generate an image. The image changes according to the phase shift between the ultrasonic signal transmitted into the material and the echo signal, which, in turn, can be utilised to determine the presence and depth of a flaw or boundary in the material.

Discrete-Ordinates Solutions of the Radiative Transport Equation for Rectangular Enclosures

Abstract: Utilisation de la methode des Sn ordonnees discretes au calcul numerique du transfert radiatif de chaleur dans une enceinte rectangulaire bidimensionnelle remplie d'un milieu gris absorbant, emissif et diffusant isotrope. Presentation des resultats pour les approximations S 2 , S 4 et S 6 et comparaison aux solutions exactes obtenues par la methode numerique des zones de Hottel

U.S. program on materials technology for ultra-supercritical coal power plants

Abstract: The efficiency of conventional fossil power plants is a strong function of the steam temperature and pressure. Research to increase both has been pursued worldwide, since the energy crisis in the 1970s. The need to reduce CO2 emissions has recently provided an additional incentive to increase efficiency. More recently, interest has been evinced in advanced combustion technologies utilizing oxygen instead of air for combustion. The main enabling technology in achieving the above goals is the development of stronger high temperature materials. Extensive research-and-development programs have resulted in numerous high-strength alloys for heavy section piping and for tubing needed to build boilers. The study reported on here is aimed at identifying, evaluating, and qualifying the materials needed for the construction of the critical components of coal-fired boilers that are capable of operating with steam at temperatures of 760 °C (1400 °F) and pressures of 35 MPa (5000 psi). The economic viability of such a plant has been explored. Candidate alloys applicable to various ranges of temperatures have been identified. Stress rupture tests have been completed on the base metal and on welds to a number of alloys. Steamside oxidation tests in an autoclave at 650 °C (1200 °F) and 800 °C (1475 °F) have been completed. Fireside corrosion tests have been conducted under conditions simulating those of waterwalls and superheater/reheater tubes. The weldability and fabricability of the alloys have been investigated. The capabilities of various overlay coatings and diffusion coatings have been examined. This article provides a status report on the progress achieved to date on this project.

Three-dimensional radiative heat-transfer solutions by the discrete-ordinates method

Abstract: Radiative heat transfer in a three-dimensional participating medium was predicted using the discrete-ordinates method. The discrete-ordinates equations are formulated for an absorbing, anisotropically scattering, and re-emitting medium enclosed by gray walls. The solution strategy is discussed and the conditions for computational stability are presented. Several test enclosures are modeled. Results have been obtained for the S2, S4, S6, and S8 approximation s that correspond to 8, 24, 48, and 80 fluxes, respectively, and are compared with the exact-zone solution and the P3 differential approximation. Solutions are found for conditions that simulate absorbing media and isotropically and anisotropically scattering media. Solution accuracy and convergence are discussed for the various flux approximations. The S4, S6, and S8 solutions compare favorably with the other methods and can be used to predict radiant intensity, incident energy, and surface heat flux. A an bn B C E G / L n q r S x y z a /U,,£,TJ p a a © V Nomenclature = north-south areas, m2 = coefficients of a Legendre series = coefficients of a modified Legendre series = east-west areas, m2 = front-back areas, m2 = emissive power ( = aT4), W/m2 = incident energy, /4w/d6, W/m2 = radiant intensity, W/(m2 • Sr) = enclosure dimension, m = unit normal = heat flux, W/m2 = position vector, m = source term, W/m3 = volume of pth control volume, m3 = weight function in a direction - m (fractional area of a unit sphere) = coordinate, m = coordinate, m = coordinate, m — finite-difference weighting factor = extinction coefficient, a -f K,m~l = surface emittance = absorption coefficient, m"1 = ordinates p = cos0, £ = sin0 sin , TJ = sinG cos = outgoing direction of radiation = phase function = surface reflectance = scattering coefficient, m"1 = Boltzmann's constant, 5.669 X 1(T 8 W/(m2