Michael W. Golay

Droplet Impacts Upon Liquid Surfaces

The absorption and rebounding of single droplets and streams of droplets (of diameter less than 1200 micrometers) impacting upon the surface of a deep liquid have been examined experimentally. Conservation of mechanical energy and momentum have been used to explain rebounding droplet interactions, and impaction criteria have been established regarding the absorption of droplet streams. Surface tension is the dominant mechanism governing the observed behavior. Single droplets were never observed to rebound.

Modular design and construction techniques for nuclear power plants

Abstract Modularization has been proposed as a nuclear power plant design-fabrication approach for increasing the quality and reducing the costs of future plants. The work reported describes a methodology for making the modular design and construction process more systematic and efficient. This methodology is applied to both the design and fabrication processes for power plant modules. The design process is enhanced by the utilization of a matrix reordering technique that reveals natural groupings in complex data sets. This technique allows a layout which groups plant systems functionally so that modules increase self-sufficiency and minimize inter-module interaction costs. In an illustration of modular design the ship fabrication methods of product work breakdown structure are applied to a modular nuclear power plant to be built at an on-site factory facility. A comparison of a new modular power plant and a conventional power plant design is performed. Cost penalty indices are defined in order to guide maximization of the economic benefits of a modular design. Economic analyses, for both modular and conventional construction methods, are performed over a range of construction schedules and monetary interest rates to illustrate the potential savings of modular construction. The results of the analyses reported here indicate a typical potential savings of 15% in the capital cost of the modular nuclear power plant versus a conventional one. The most interesting result of this work is that the potential savings derive equally from the design and construction processes.

An integrated method for comprehensive sensor network development in complex power plant systems

Abstract The rapid advancement of powerful monitoring devices and computers permits one to design a comprehensive sensor network as the foundation of an efficient plant condition monitoring and diagnosis system. For the development of such a comprehensive sensor network in complex power plant systems, the work presented here describes the rationale and implementation of an integrated method incorporating a structural system hierarchy and a functional system hierarchy, a fault–symptom matrix, sensor selection criteria, use of a sensor installation feasibility study, and advanced instrumentation steps. In selecting instrumentation to use we include the state of the art technologies concerning data processing and data integration as a means of extending the plants feasible diagnostic coverage. The application of the design technique described here to the specific example component of the turbine generator demonstrates how each step of the presented method contributes to completion of the sensor network development in a systematic way.

A method for reduction of numerical diffusion in the donor cell treatment of convection

Abstract This article is concerned with the donor cell treatment of convection in numerical simulations of convective-diffusive flow. The two sources of numerical diffusion in this treatment, truncation error and crossflow diffusion, are explained and quantified. Truncation error occurs due to the use of approximate profile assumptions while crossflow diffusion arises due to cell-wise homogenization of the convected quantity in multidimensional problems. Crossflow diffusion is the dominant source of error in many cases. A corrective scheme is introduced in this article which compensates for the effect of crossflow diffusion by reducing the effective anisotropic diffusion coefficient used in the diffusion portion of the simulation. Relationships are developed quantifying the crossflow diffusional error and requirements for explicit numerical stability when the error correction technique is employed. The magnitudes of the diffusional error and the improvements realized using the corrective scheme are demonstrated through computational examples.

Comparative performance evaluation of current design evaporative cooling tower drift eliminators

Abstract An analysis of the performance of standard industrial evaporative cooling tower drift eliminators using both numerical simulation methods and experimental techniques is reported. The simulation methods make use of the computer code SOLA as a subroutine of the computer code DRIFT to calculate the two-dimensional laminar flow velocity field and pressure loss in a drift eliminator geometry. This information is then used in the main program to obtain the eliminator collection efficiency by performing trajectory calculations for droplets of a given size by a fourth order Runge-Kutta numerical method. The experimental technique makes use of laser light scattering techniques for measurement of the droplet size spectra both at the inlet and outlet of the eliminator. From these measured spectra, the collection efficiency as a function of droplet size can be deduced. The results are found to be in good agreement with calculated collection efficiencies using no-slip boundary conditions. The pressure loss data for the eliminators are measured by an electronic manometer. The agreements between the measured and calculated pressure loss are good. The results show that both particle collection efficiency and pressure loss increase as the eliminator geometry becomes more complex, and as the flow rate through the eliminator increases. In ascending order of collection efficiency the eliminators tested are ranked as follows: sinus-shaped eliminator, three-segment eliminator and zig-zag eliminator.

Comparison of methods for measurement of cooling tower drift

Abstract An international comparison of methods for measurement of cooling tower drift has been performed at the Massachusetts Institute of Technology. Participants from Belgium, the United States and the Federal Republic of Germany participated in measurements of a spectrum of test environments, which span the range of cases which would typically be encountered in operating cooling towers. The environments differed according to droplet mass flux, droplet size distribution and gas speed. A wind tunnel was built to provide the various test environments, and a special optical drift measurement system was built to permit simultaneous monitoring of the environment sampled in the tests. Cases tested included both mechanical and natural draft cooling tower environments. Among the types of instruments tested are the pulsed laser light scattering system (PILLS), sensitive paper and other sensitive surface droplet impaction systems, isokinetic drift mass flux measurement systems and photographic systems. The results indicate that the instruments tested vary widely in their capabilities, with droplet sizing instruments being more effective in low load, small droplet size spectrum situations, and isokinetic mass and chemical assay techniques being most accurate in high load, large droplet distribution cases. Instruments relying upon thermodynamic state measurements in most cases agreed mutually within an order of magnitude. Their major source of error is believed to arise in the measurement of the gas stream relative humidity. This quantity is necessary for inferring the drift mass flux from the measurement provided by such instruments, which is the mixture saturation deficit or excess. For these tests the relative humidity was typically ⩽ 98%.

Light scattering device for sizing and velocimetry of large droplets utilizing a ring-shaped laser beam.

A newly developed light scattering device for sizing and velocimetry of large droplets is described. A novel beam shaping technique is employed in conjunction with a laser operating in the circular TEM(01) (doughnut) mode as a light source to achieve a ring-shaped source beam. This particular beam geometry allows definition of a sheetlike scattering volume with an approximately constant power density across it resulting in improved sizing and sampling accuracy. The size resolution of the instrument is better than 7%, and the overall sizing accuracy for an input size range of 30 dB (droplets of ~45-1500 microm in radius) is ~10%. While the instrument reported in this paper was designed to analyze water droplets entrained in air, it should also be useful in other sizing applications if appropriate modifications are made.

Diagnostic entropy: a quantitative measure of the effects of signal incompleteness on system diagnosis

Abstract A set of measures quantifying the effects of signal incompleteness upon system diagnosis are defined and investigated. The most important is diagnostic entropy, a new quantitative measure of the effects of signal incompleteness upon system uncertainty. Diagnostic entropy is defined as the average uncertainty of a system when the system is indicated to be in an undesired state. This measure appears to be more useful for quantifying the difficulty of system diagnosis than conventional system entropy or conditional system entropy measures due to its relevance to the difficulty of human diagnosis of the system when it is in an undesired state. The magnitude of the diagnostic entropy is shown to be usually larger than that of the conditional entropy for typical highly reliable systems. This means that the uncertainty of the system is larger than usual when a reliable system is in an undersired state. We also suspect, but have not identified, the existence of a relationship between the diagnostic entropy of a system and the average physiological stress of human operators in diagnosing the system.

Nuclear power plant design innovation through simplification

Abstract In light of growing interest in LWR redesign and simplification of currently-used systems, an overview of the problems arising in implementation of design simplification can be valuable. The concept of nuclear plant design simplification is explored with the goal of achieving useful results. Two schools of thought - performing numerous individual simplification exercises or developing a general methodology - are explained. The results of a study of eliminating the soluble poison control function in PWRs are reported. Design, reliability, safety, licensing, economics and alternative schemes are addressed but no conclusive answer is achieved. Given the inadequacies of this exercise, a comprehensive simplification process including criteria definition, proposal prioritization and specification, development of an analytical evaluation model, implementation and data requirements is proposed. The reported work demonstrates the complexity of the design simplification process but also provides a framework for future progress.

Numerical modeling of buoyant plumes in a turbulent, stratified atmosphere

Sponsored by the Consolidated Edison Company of New York and Northeast Utilities Service Corporation.