The effects of enhancement devices on flow boiling heat transfer in circular coolant channels, which are heated over a fraction of their perimeters, are studied. The variations were examined in both the mean and local (axial, and circumferential) heat transfer coefficients for a circular coolant channel with either smooth walls or with both a twisted tape and spiral finned walls. Improvements were initiated in the present data reduction analysis. These efforts should lead to the development of heat transfer correlations which include effects of single side heat flux and enhancement device configuration. It is hoped that a stage will be set for the study of heat transfer and pressure drop in single sided heated systems under zero gravity conditions. Author N89-27980*# National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. EXPERIENCE WITH ADVANCED INSTRUMENTATION IN A HOT SECTION CASCADE Frederick C. Yeh and Herbert J. Gladden 1989 14 p Prepared for presentation at the Winter Annual Meeting of the American Society of Mechanical Engineers, San Francisco, CA, 10-15 Dec. 1989 (NASA-TM-102294; E-4962; NAS 1.15:102294) Avail: NTIS HC A03/MF A01 CSCL 20D The Lewis Research Center gas turbine Hot Section Test Facility was developed to provide a real engine environment with known boundary conditions for the aerothermal performance evaluation and verification of computer design codes. This verification process requires experimental measurements in a hostile environment. The research instruments used in this facility are presented, and their characteristics and how they perform in this environment are discussed. The research instrumentation consisted of conventional pressure and temperature sensors, as well as thin-film thermocouples and heat flux gages. The hot gas temperature was measured by an aspirated temperature probe and by a dual-element, fast-response temperature probe. The data acquisition mode was both steady state and time dependent. These experiments were conducted over a wide range of gas Reynolds numbers, exit gas Mach numbers, and heat flux levels. This facility was capable of testing at temperatures up to 1600 K, and at pressures up to 18 atm. These corresponded to an airfoil exit Reynolds number range of 0.5 x 10(6) to 2.5 x 10(6) based on the airfoil chord of 5.55 cm. The results characterize the performance capability and the durability of the instrumentation. The challenge of making measurements in hostile environments is also discussed. The instruments exhibited more than adequate durability to achieve the measurement profile. About 70 percent of the thin-film thermocouples and the dual-element temperature probe survived several hundred thermal cycles and more than 35 hr at gas temperatures up to 1600 K. Within the experimental uncertainty, the steady-state and transient heat flux measurements were comparable and consistent over the range of Reynolds numbers tested. Author and oscillations resulting from the numerical approximation of the convection term, it is common practice to use first order upwind differencing. For example, first order upwind differencing is used in codes like COMMIX and PHOENICS. However, in problems characterized by high Peclet numbers, this approach is highly inaccurate unless an excessive number of nodes is used. To eliminate this difficulty, a method of grid adaptation using central differencing in one-dimensional problems was presented. In the effort to extend this approach to 2-D and 3-D problems a new method was developed for multidimensional problems that is superior to first order upwind differencing even for a few non-adaptive grid points. This method is presented in this work. DOE N89-27982# Argonne National Lab., IL. Reactor Analysis and Presented at the 3rd American Society of Civil Engineers/ASME Conference, San Diego, CA, 9 Jul. 1989 (Contract W-31-109-eng-38) (DE89-013426; CONF-890794-1) Avail: NTIS HC A03/MF A01 Knowledge of local specific interfacial area is required for analysis and prediction of transient and steady characteristics of two-phase flow systems using the two-fluid models. Based on a survey of published work on the subject of specific interfacial area, it is recognized that there is virtually no data base for local specific interfacial area. This report describes the ongoing development of experimental techniques for measurement of local specific interfacial area in gas-liquid and liquid-liquid two-phase systems. Mathematical relations between local specific interfacial area and measurable quantities are derived based on kinematics and geometry. Two methods for determining local specific interfacial area are identified; both entail detection of passage of interfaces through fixed locations in the flow field. A multiple-sensor electrical-resistivity-probe technique is being developed for determination of local specific interfacial area in vertical gas-liquid bubbly flows. The technique consists of simultaneous measurements at two or four locations in the two-phase flow field of the local electrical resistivity of the two-phase mixture. Methods for data analysis are described. Limitations of the technique are DOE briefly discussed. N89-27983# Du Pont de Nemours (E. I.) and Co., Aiken, SC. SUBCOOLED BOILING OF DOWNWARD FLOW IN A B. S. Johnston 1989 21 p Presented at the ASME/AIChE National Heat Transfer Conference, Philadelphia, PA, 6-9 Aug. 1989 Submitted for publication (Contract DE-AC09-76SR-00001) (DE89-005320; DP-MS-88-217; CONF-890819-1) Avail: NTIS HC A03/MF A01 Measurements of steady state pressure drop were made for the downward flow of water in a vertical annulus at low pressure. The inner wall was uniformly heated to allow subcooled boiling. The minimum in the test section demand curve was compared to the onset of significant void (OSV) at the exit of the annulus. As expected, OSV was found to serve as a conservative predictor for avoiding flow excursions. However, at low flow rates the demand curve minima were significantly different from those obtained for upward flow. Similarly, conditions for OSV in downward flow were not predicted by the correlation of Saha and Zuber. More data are needed to establish a general correlation for OSV in downward flow. N89-27984# DOE Materials and Argonne National Lab., IL. Components Technology Div. ANALYSIS OF PRESSURE DROP AND HEAT TRANSFER DATA FROM THE REVERSING FLOW TEST FACILITY Paul D. Roach and Kenneth J. Bell May 1989 33 p (Contract W-31-109-eng-38) (DE89-013907; ANL/MCT-88/2) Avail: NTIS HC A03/MF A01 The Reversing Flow Test Facility is part of the heat engine R and D capabilities at Argonne National Laboratory. The facility permits the study of heat transfer and pressure drop under conditions of rapidly reversing flow. The results are summarized that were obtained from more than 100 data sets that cover a wide range of temperatures, pressures, and frequencies. Pressure drop data are presented as normalized pressure drop vs. the Reynolds number calculated from the amplitude of the oscillatory flow. Heat transfer data for the regenerators are presented as regenerator effectiveness vs. Reynolds number. Three significant conclusions are derived from the analysis of the data: (1) no frequency dependence is observed in either the pressure drop or the heat transfer data; (2) the measured pressure drops for the heater and coolers are distinctly higher than those calculated from steady-flow correlations; and (3) the heat transfer coefficient in the heater is about 80 percent of that predicted by steady flow correlations. The correlations presented provide the basis for improving existing models. DOE N89-27985# Von Karman Inst. for Fluid Dynamics, Rhode-Saint-Genese (Belgium). AN INTRODUCTION TO COMPUTATIONAL FLUID DYNAMICS 1989 483 p Lecture series held in Rhode-Saint-Genese, Belgium, 16-20 Jan. 1989 (VKI-LS-1989-02; ISSN-0377-8312; ETN-89-94967) Avail: NTIS HC A21/MF A01 Boundary layer equations and methods of solution, finite volume techniques, finite element techniques, and implicit time dependent methods for inviscid and viscous compressible flows, with a discussion of the concept of numerical dissipation, are presented. For individual titles, see N89-27986 through N89-27990. N89-27991# Lehigh Univ., Bethlehem, PA. C. R. Smith and J. D. A. Walker 15 Apr. 1989 73 p (AD-A208624; AFOSR-89-0689TR) Avail: NTIS HC A04/MF A01 CSCL 20/4 The results and accomplishments of a combined analyticalexperimental research program, aimed at understanding and modeling the three-dimensional vortex interactions that take place in turbulent boundary layers, are described. The central theme of the program is that hairpin vortices are the basic building block of boundary-layer turbulence and that many of the observed dynamic features of turbulent shear flows can be explained in terms of how hairpin vortices interact with the background shear, with each other and the viscous flow near solid walls. A basic intent of the program is to cross-compare detailed experimental flow visualization-imaging studies of well-defined three-dimensional hairpin vortices with computational studies of the behavior, evolution and induced effects of comparable vortices. Based on these investigations, a model of the dynamics of turbulent flows near a wall is proposed. GRA N89-27992# Group. Aerospace Corp., El Segundo, CA. Engineering A METHOD FOR CALCULATING ASYMMETRIC FLOW THROUGH NOZZLES Final Report, Jan. - Aug. 1988 Rudolf X. Meyer Jan. 1989 24 P (Contract F04701-88-C-0089) (AD-A209689; TR-0088(4392-11)-1; SD-TR-89-20) Avail: NTIS HC A03/MF A01 CSCL 20/4 The asymmetric steady state, inviscous, adiabatic flow of a perfect gas through a subsonic/supersonic nozzle is considered. The nozzle itself is either of rectangular cross section or is axisymmetric. A first-order small asymmetry induced by an entrance flow which is oblique to the nozzle axis and has a transverse pressure gradient is allowed. The cross section of the nozzle is assumed to vary only slowly as a function of the axial distance; the case considered here is therefore an extension of the well known theory of the quasi-1-D flow of a perfect gas treated in standard textbooks. An integral method is used to obtain approximate results. The method is simple, yet in a test case (supersonic flow at an angle of attack through a rectangular channel) where the exact first-order result is known, a comparison shows surprisingly good agreement. Numerical results are tabulated for axisymmetric nozzles with polynomial Mach number dependence. GRA N89-27993# Clarkson Univ., Potsdam, NY. Dept. of Mathematics and Computer Science. NONLINEAR WAVES Mark J. Ablowitz and Athanassios S. Fokas 15 Jun. 1989 9 p (Contract N00014-88-K-0447) (AD-A209822) Avail: NTIS HC A02/MF A01 CSCL 20/4 The investigators have been working in the general area of nonlinear wave propagation for over twenty years. The main focus herein is the understanding of the nonlinear phenomena involved with the wave propagation arising in physical problems. The work has application to numerous areas of physics, engineering and mathematics. Applications include fluid dynamics, waves in stratified fluids, surface gravity waves and wave excitation phenomena related to moving pressure distributions; numerical approximation and computation; nonlinear optics; and plasma physics. Moreover the study of solutions to some of the underlying nonlinear evolution equations has led naturally to the investigation and new results in the separate but closely related field of inverse scattering. Developments to both one and multidimensional inverse problems were made. 35 INSTRUMENTATION AND PHOTOGRAPHY GRA Includes remote sensors; measuring instruments and gages; detectors; cameras and photographic supplies; and holography. For aerial photography see 43 Earth Resources and Remote Sensing. For related information see also 06 Aircraft Instrumentation, and 19 Spacecraft Instrumentation. N89-27994*# Microtronics Associates, Pittsburgh, PA. HIGH DYNAMIC RANGE INFRARED RADIOMETRY AND IMAGING Final Report Darryl D. Coon, R. P. G. Karunasiri, and K. M. S. V. Bandara Aug. 1988 33 p Original contains color illustrations (Contracts NAS5-30282; DASG60-86-C-0075) (NASA-CR-183439; NAS 1.26:183439) Avail: NTIS HC A03/MF A01 CSCL 14B The use is described of cryogenically cooled, extrinsic silicon infrared detectors in an unconventional mode of operation which offers an unusually large dynamic range. The system performs intensity-to-frequency conversion at the focal plane via simple circuits with very low power consumption. The incident IR intensity controls the repetition rate of short duration output pulses over a pulse rate dynamic range of about 10(6). Theory indicates the possibility of monotonic and approx. linear response over the full dynamic range. A comparison between the theoretical and the experimental results shows that the model provides a reasonably good description of experimental data. Some measurements of survivability with a very intense IR source were made on these devices and found to be very encouraging. Evidence continues to indicate that some variations in interpulse time intervals are deterministic rather than probabilistic. Author N89-27995*# National Aeronautics and Space Administration. Langley Research Center, Hampton, VA. PHOTOGRAMMETRIC TECHNIQUE FOR IN-FLIGHT RANGING OF TRAILING VORTICES USING ENTRAINED BALLOONS Walter L. Snow, Alpheus W. Burner, and William K. Goad 1989 1 p (NASA-TM-4129; L-16551; NAS 1.15:4129) Avail: NTIS HC A03/MF A01 CSCL 14E A method for experimentally determining the radial distance of a probe aircraft from a trailing vortex is described. The method relies on photogrammetric triangulation of targets entrained in the vortex core. The theory and preliminary testing were described using laboratory mock-ups. Solid state video cameras were to provide data at 300 Hz rates. Practical methods for seeding the vortex are under separate investigation and are not addressed. Author A method has been developed that can determine the motion of a stereo-camera platform and the relative three-dimensional position of image features using data from stereo image sequences as input. In the first step of the method, the motion is found from a set of linear equations whose coefficients are averages of functions of the measured positions and velocities of image features. In the second step of the method, the same equations are used with the computed translational velocities to determine the correspondence of features in the left and right images. Separate theories were developed which use the full optical flow as input or the normal flow at contours as input. The theory using the full optical flow as derived for six-component, threedimensional motions, while the theory for the normal flow was derived for translational motion only. The theories require only that the data in the left and right images come from regions corresponding to objects with the same relative velocity. Thus, in the case of a camera platform moving through a stationary environment these regions include the entire images. The theories have been tested with synthetic image sequences and appear to be promising. A stereo camera system for use in the laboratory has just been constructed and will be used to test the methods with real images from laboratory scenes. In the following, the theory for motion recovery with the full optical flow data is presented first. This is followed by the theory for the recovery of the translational motion from the normal flow data. A discussion of the determination of stereo correspondence follows. Then the results of experiments with synthetic images are presented and the conclusions are given. DOE A01 During the past year, considerable effort was applied to the development of scintillating fiber detectors in several areas: new scintillation liquids and studies of their fluorescence properties; new fluorescent dyes based on non-intramolecular proton transfer, new dyes based on intramolecular proton transfer; incorporation of these new dyes in plastic (polystyrene) and liquid scintillation solutions; development of small cross section glass capillaries for the containment of liquid scintillators; studies of waveguide characteristics; and studies of image intensifier phosphor screen characteristics. Other areas are: initial steps to form a collaboration to study and develop appropriate new properties of the Solid State Photomultiplier. Construction of a new laboratory at Notre Dame to enhance the capabilities for further measurements and studies; and organization of and execution of a Workshop on Scintillating Fiber Detector Development for the SSC, held at Fermilab, November 14 to 16, 1988. N89-27998*# DOE National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. COMPENSATION FOR EFFECTS OF AMBIENT TEMPERATURE ON RARE-EARTH DOPED FIBER OPTIC THERMOMETER G. Adamovsky, J. L. Sotomayor, M. J. Krasowski, and J. G. Eustace 14 p Presented at (John Carroll Univ., Cleveland, OH.) 1989 the Fiber Optic and Laser Sensors 7, Boston, MA, 5-8 Sep. 1989; sponsored by the Society of Photo-Optical Instrumentation Engineers (Grant NAG3-984) (NASA-TM-102282; E-4946; NAS 1.15:102282) Avail: NTIS HC A03/MF A01 CSCL 14B Variations in ambient temperature have a negative effect on the performance of any fiber optic sensing system. A change in ambient temperature may alter the design parameters of fiber optic cables, connectors, sources, detectors, and other fiber optic components and eventually the performance of the entire system. The thermal stability of components is especially important in a system which employs intensity modulated sensors. Several referencing schemes have been developed to account for the variable losses that occur within the system. However, none of these conventional compensating techniques can be used to stabilize the thermal drift of the light source in a system based on the spectral properties of the sensor material. The compensation for changes in ambient temperature becomes especially important in fiber optic thermometers doped with rare earths. Different approaches to solving this problem are searched and analyzed. N89-27999*# Author National Aeronautics and Space Administration. Lewis Research Center, Cleveland, OH. SPECKLE INTERFEROMETRY USING FIBER OPTIC PHASE STEPPING Carolyn R. Mercer and Glenn Beheim Aug. 1989 9 p Presented at the Symposium on Optical and Optoelectronic Applied Science and Engineering, San Diego, CA, 6-11 Aug. 1989; sponsored in part by Society of Photo-Optical Instrumentation Engineers (NASA-TM-102331; E-5040; NAS 1.15:102331) Avail: NTIS HC A02/MF A01 CSCL 14B A system employing closed-loop phase-stepping is used to measure the out-of-plane deformation of a diffusely reflecting object. Optical fibers are used to provide reference and object beam illumination for a standard two-beam speckle interferometer, providing set-up flexibility and ease of alignment. Piezoelectric fiber-stretchers and a phase-measurement/servo system are used to provide highly accurate phase steps. Intensity data is captured with a charge-injection-device camera, and is converted into a phase map using a desktop computer. The closed-loop phase-stepping system provides 90 deg phase steps which are accurate to 0.02 deg, greatly improving this system relative to open-loop interferometers. The system is demonstrated on a speckle interferometer, measuring the rigid-body translation of a diffusely reflecting object with an accuracy + or 10 deg, or roughlyor 15 nanometers. This accuracy is achieved without the use of a pneumatically mounted optics table. N89-28000# Author Lawrence Livermore National Lab., CA. Environmental Sciences Div. HIGH-TEMPERATURE OPTICAL-FIBER PH SENSOR Final Report Jun. 1989 31 P Prepared for S. M. Angel and J. F. Poco Electric Power Research Inst. (Contract W-7405-eng-48) (DE89-014103; UCRL-21083; EPRI-RP-2614-5) Avail: NTIS HC A03/MF A01 The results of research on high-temperature optical-fiber pH sensors will be presented. It is shown that these sensors (optrodes) can be made to work in very-high-temperature (300 C) water for long periods and that it is possible to measure pH using fluorescent inorganic ions doped into solid matrices. A high-temperature pH optrode can be made using these techniques; however, more research is needed into the chemistry of the carrier matrices and fluorescent dopants. New types of materials should be studied, including solid polymer ionic conductors and high-temperature epoxies. Particular emphasis should be placed on developing an Eh optrode because it also will be very useful and probably more easily developed. Transition-metal ions and complexes, as well as certain stable organic dyes, (materials that are very stable at high temperature) should also be investigated as dopants. DOE N89-28001# Army Missile Command, Redstone Arsenal, AL. Research Directorate. COMPUTER GENERATED MATCHED FILTERS WITH SPATIAL FREQUENCY TAILORING Final Technical Report, Jun.- Oct. 1988 Don A. Gregory, Kevin Worchester, Larry Z. Kennedy, and J. Computer generated Fourier transform matched filters have been constructed using e-beam lithography. These filters were then evaluated by placing them in a VanderLugt optical correlator and addressing them with the original scene used to make the filters. Results show that the spatial frequency content of a filter may be tailored so as to obtain good signal-to-noise correlations while maintaining high diffraction efficiency. GRA N89-28002# SRI International Corp., Menlo Park, CA. (AD-A207297; DPG-FR-89-901) Avail: NTIS HC A03/MF A01 CSCL 17/5 Infrared differential adsorption lidar (IR DIAL) was used for real time vapor concentration measurements. As part of the 1988 Thermal Image Test Program, a correlation study was made between conventional sequentially aspirated bubblers and the DIAL system. Six lidar bubbler correlation trials were performed using diethyl malonate (DEM) as a simulant. The DEM was disseminated from a 100 m line source with the lidar aimed along a single line of sight directly over 21 bubbler stations spaced at approximately 30 m intervals. High correlations between lidar and bubbler DEM vapor concentration measurements were observed. For the 1 min integration period generally used the lidar sensitivity limit is estimated to be less than 1mg/cu m for DEM. GRA N89-28003# Naval Research Lab., Washington, DC. EFFICIENT SECOND HARMONIC CONVERSION OF BROADBAND HIGH-PEAK-POWER ND:GLASS LASER RADIATION USING LARGE-APERTURE KDP CRYSTALS IN QUADRATURE M. Pronko, R. Lehmberg, S. Obenschain, C. Pawley, C. Manka, and R. Eckardt (Stanford Univ., CA.) 23 Jun. 1989 41 p (Contract DE-A103-79DP-40092) (DE89-012961; NRL-MR-6453) Avail: NTIS HC A03/MF A01 We have investigated the second harmonic conversion efficiency of broadband Nd:glass laser light (delta nu/c is less than 30/cm FWHM). Using two KDP crystals in a quadrature arrangement we obtained energy conversion efficiencies approximately 55 percent with an initial bandwidth for the fundamental of delta nu/c is approximately 17/cm FWHM. For these conditions, we observed a modest increase (approximately 70 percent) in the harmonic bandwidth (FWHM) relative to the fundamental. The usual theory of three-wave mixing in dispersive birefringent nonlinear crystals is extended to describe the broadband harmonic conversion process; the generalized theory includes the statistical properties of the light and phase mismatch effects on the spectral components in the complex field amplitudes. Good agreement is shown between the code calculations and the measurements. DOE N89-28004*# Planning Research Corp., Hampton, VA. Aerospace Technologies Div. APPROACHES TOWARD A BLUE SEMICONDUCTOR LASER Report, Sep. 1987 - Sep. 1988 I. Ladany Washington Sep. 1989 90 p (Contract NAS1-18000) (NASA-CR-4252; NAS 1.26:4252) Avail: NTIS HC A05/MF A01 CSCL 20E Possible approaches for obtaining semiconductor diode laser action in the blue region of the spectrum are surveyed. A discussion of diode lasers is included along with a review of the current status of visible emitters, presently limited to 670 nm. Methods are discussed for shifting laser emission toward shorter wavelengths, including the use of II-IV materials, the increase in the bandgap of III-V materials by addition of nitrogen, and changing the bandstructure from indirect to direct by incorporating interstitial atoms or by constructing superlattices. Non-pn-junction injection methods are surveyed, breakdown, including avalanche Langmuir-Blodgett diodes, heterostructures, carrier accumulation, and Berglund diodes. Prospects of inventing new multinary semiconducting materials are discussed, and a number of novel materials described in the literature are tabulated. New approaches available through the development of quantum wells and superlattices are described, including resonant tunneling and the synthesis of arbitrary bandgap materials through multiple quantum Author wells. N89-28005# California Univ., Berkeley. Lawrence Berkeley Lab. Accelerator and Fusion Research Div. HIGH-POWER, HIGH-EFFICIENCY FELS Andrew M. Sessler Apr. 1989 17 p Presented at the CERN Accelerator School, Chester, United Kingdom, 6 Apr. 1989 (Contract DE-AC03-76SF-00098) (DE89-013002; LBL-27035; CONF-8904228-2) Avail: NTIS HC A03/MF A01 High power, high efficiency free electron lasers (FELS) require tapering, as the particles loose energy, so as to maintain resonance between the electromagnetic wave and the particles. They also require focusing of the particles (usually done with curved pole faces) and focusing of the electromagnetic wave (i.e., optical guiding). In addition, one must avoid transverse beam instabilities (primarily resistive wall) and longitudinal instabilities (ie., DOE sidebands). |