Surrogate wastes of specific interest to DOE/DP production facilities (Hanford and Rocky Flats), and the electronics industry have been successfully processed in a laboratory-scale, supercritical water oxidation flow reactor. In all cases, the observed destruction/reduction efficiencies for the organic components were in excess of 99.9%, limited by instrumentation detection capability. Separation of the inorganic components of the Hanford process stream was more difficult to accomplish than destruction of the organic component. Large fractions of all metals contained in this stream were found both in the solids separator effluent and in deposits removed from the reactor. Mass closure was not achieved. Of the process stream`s non-metallic, inorganic components, the sulfates and phosphates precipitated, while the nitrates tended to stay in solution. The inorganic material that did precipitate from the simulated Hanford mixed waste accumulated in zones that may be associated with changes in the chemical and physical properties of the supercritical fluid. Corrosion is expected to be a significant problem. Witness wires of Inconel 625, Hastalloy C-276, and titanium placed in the preheater, reactor and cooldown exchanger indicated selective dissolution of chromium, nickel, and molybdenum for some conditions, and non-selective dissolution for others. While these results are very promising, further researchmore » is required to evaluate the scalability, reliability, and economics of SCWO reactor components and systems, particularly for mixed wastes. Future research must explore a parameter space (temperature, pressure, pH, residence time, etc.) focused on selecting conditions and materials for specific process streams.« less
Neutron radiography is discussed as a line-of-sight gasdynamic diagnostic technique for studying internal flows in opaque, complicated geometry flow systems which are not optically accessible. Because neutron attenuation is very sensitive to nuclear structure, many material combinations that are difficult or impossible to image with optical techniques or x rays can be imaged by means of neutron radiography. The problem presented to demonstrate the neutron radiographic technique is the determination of the time-resolved gas–gas interface location inside a gas transfer system composed of three pressure vessels connected by opaque, thick-walled tubing.
T aspects of the stability of rotating stratified fluids have been discussed by several authors. If viscous effects are neglected, von Karman derived a stability criterion for a rotating liquid by considering the role played by pressure gradient and centrifugal force. For a steady flow, the centrifugal force, pv/r, must be balanced by the pressure gradient. However, if a ring of fluid at radius rx is displaced to a radius r2 (where r2 > rj, the centrifugal force experienced by the ring will be-p^rf/rDv?. For stability, the pressure gradient, p2vt/r2, at the new position must be greater than this centrifugal force. Thus, von Karman's stability criterion becomes d(pvr)/dr ^ 0. Yih has shown that if the effects of viscosity and thermal diffusivity are taken into account, the von Karman stability criterion is neither necessary nor sufficient for stability. Rather, the more restrictive stability criteria dp/dr ^ 0 and d(vr)/dr ^ 0 must be satisfied. This Note presents some experimental results of the stability of the rotating flow that results from the tangential injection of a gas stored at high pressure into a closed cylindrical test vessel containing a gas of different density.
A transient pressure–volume–temperature (PVT) experimental technique for determining true bulk gas temperature during gas discharge from a vessel to the atmosphere is described. The bulk temperature obtained is valid no matter how nonuniform gas temperature is inside the vessel and accounts for all modes of heat transfer during discharge.
In this paper coherent anti-Stokes Raman spectroscopy (CARS) measurements of gas temperature and density in an internal combustion (IC) engine are reported. Two coherent Raman techniques, CARS and inverse Raman spectroscopy (IRS), are also compared with spontaneous Raman scattering for use in internal combustion engine experiments. For sooting environments at engine pressures CARS is shown to have the greatest promise.
A turbulent reacting flow working group has been established through the Department of Energy/Office of Basic Energy Sciences. The purpose of this group is to establish and maintain a strong interaction and active dialogue between workers currently involved in modeling turbulent reacting flows and those involved in related experiments. One objective of this collaboration is to develop an increased understanding of the fundamental interaction between the chemical and fluid dynamical processes occurring in chemically reacting flows and to utilize this understanding to improve predictive capabilities for turbulent combustion. Regular members, who represent academia, private industry, and national laboratories, and guests participate in the meetings. Several guests are invited to each meeting to provide an influx of different ideas and opinions to the discussions. This document is a summary of the discussions that took place during the seventh and eighth meetings, which were held at California Institute of Technology, Pasadena, CA, March 25-26, 1986 and Yale University, New Haven, CT, October 13-14, 1986, respectively.
