An investigation of heat transfer from wall to steam near the critical region
Convective heat transfer between high parameter steam and solid wall of nickel or steel tubing in supercritical region
STEAM↗
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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Forbidden tangential orbit transfers between intersecting Keplerian orbits
The classical problem of tangential impulse transfer between coplanar Keplerian orbits is addressed. A completely analytic solution which does not rely on sequential calculation is obtained and this solution is used to demonstrate that certain choices of initial true anomaly can produce singularities in the parameters of the transfer orbit. A necessary and sufficient condition for the existence of such singularities is that the initial and final orbits intersect.
Burns, Rowland E.↗
Robust control with structured perturbations
Two important problems in the area of control systems design and analysis are discussed. The first is the robust stability using characteristic polynomial, which is treated first in characteristic polynomial coefficient space with respect to perturbations in the coefficients of the characteristic polynomial, and then for a control system containing perturbed parameters in the transfer function description of the plant. In coefficient space, a simple expression is first given for the l(sup 2) stability margin for both monic and non-monic cases. Following this, a method is extended to reveal much larger stability region. This result has been extended to the parameter space so that one can determine the stability margin, in terms of ranges of parameter variations, of the closed loop system when the nominal stabilizing controller is given. The stability margin can be enlarged by a choice of better stabilizing controller. The second problem describes the lower order stabilization problem, the motivation of the problem is as follows. Even though the wide range of stabilizing controller design methodologies is available in both the state space and transfer function domains, all of these methods produce unnecessarily high order controllers. In practice, the stabilization is only one of many requirements to be satisfied. Therefore, if the order of a stabilizing controller is excessively high, one can normally expect to have a even higher order controller on the completion of design such as inclusion of dynamic response requirements, etc. Therefore, it is reasonable to have a lowest possible order stabilizing controller first and then adjust the controller to meet additional requirements. The algorithm for designing a lower order stabilizing controller is given. The algorithm does not necessarily produce the minimum order controller; however, the algorithm is theoretically logical and some simulation results show that the algorithm works in general.
Keel, Leehyun↗
ATM Quality of Service Tests for Digitized Video Using ATM Over Satellite: Laboratory Tests
A digitized video application was used to help determine minimum quality of service parameters for asynchronous transfer mode (ATM) over satellite. For these tests, binomially distributed and other errors were digitally inserted in an intermediate frequency link via a satellite modem and a commercial gaussian noise generator. In this paper, the relation- ship between the ATM cell error and cell loss parameter specifications is discussed with regard to this application. In addition, the video-encoding algorithms, test configurations, and results are presented in detail.
Ivancic, William D.↗
Current Sounding Capability From Satellite Meteorological Observation With Ultraspectral Infrared Instruments
Ultraspectral resolution infrared spectral radiance obtained from near nadir observations provide atmospheric, surface, and cloud property information. The intent of the measurement of tropospheric thermodynamic state and trace abundances is the initialization of climate models and the monitoring of air quality. The NPOESS Airborne Sounder Testbed-Interferometer (NAST-I), designed to support the development of future satellite temperature and moisture sounders, aboard high altitude aircraft has been collecting data throughout many field campaigns. An advanced retrieval algorithm developed with NAST-I is now applied to satellite data collected with the Atmospheric InfraRed Sounder (AIRS) on the Aqua satellite launched on 4 May 2002 and the Infrared Atmospheric Sounding Interferometer (IASI) on the MetOp satellite launched on October 19, 2006. These instruments possess an ultra-spectral resolution, for example, both IASI and NAST-I have ~0.25 cm-1 and a spectral coverage from 645 to 2760 cm-1. The retrieval algorithm with a fast radiative transfer model, including cloud effects, is used for atmospheric profile and cloud parameter retrieval. The physical inversion scheme has been developed, dealing with cloudy as well as cloud-free radiance observed with ultraspectral infrared sounders, to simultaneously retrieve surface, atmospheric thermodynamic, and cloud microphysical parameters. A fast radiative transfer model, which applies to the clouded atmosphere, is used for atmospheric profile and cloud parameter retrieval. A one-dimensional (1-d) variational multi-variable inversion solution is used to improve an iterative background state defined by an eigenvector-regression-retrieval. The solution is iterated in order to account for non-linearity in the 1-d variational solution. It is shown that relatively accurate temperature and moisture retrievals can be achieved below optically thin clouds. For optically thick clouds, accurate temperature and moisture profiles down to cloud top level are obtained. For both optically thin and thick cloud situations, the cloud top height can be retrieved with relatively high accuracy (i.e., error less than 1 km). Retrievals of atmospheric soundings, surface properties, and cloud microphysical properties with the AIRS and IASI observations are obtained and presented. These retrievals are further inter-compared with those obtained from airborne FTS system, such as the NPOESS Airborne Sounder Testbed? Interferometer (NAST I), dedicated dropsondes, radiosondes, and ground based Raman Lidar. The capabilities of satellite ultra-spectral sounder such as the AIRS and IASI are investigated. These advanced satellite ultraspectral infrared instruments are now playing an important role in satellite meteorological observation for numerical weather prediction.
Zhou, Daniel K.↗
A new spectrally-invariant approach to the remote sensing of inhomogeneous clouds
Current operational satellite retrievals of cloud optical and microphysical properties go back to the Nakajima-King technique developed at the end of the 1980s. This technique is based on library calculations for plane-parallel homogeneous clouds. It often works well for overcast skies but leads to substantial errors for inhomogeneous and broken cloud fields where the plane-parallel-geometry assumption is no longer valid. The basic concept of a new technique was first introduced in nuclear physics to quantify the critical conditions of reactors. Based on the eigenvalues of the radiative transfer equation, their approach provides a powerful means to parameterize the structure of 3D media. This parameterization was later successfully applied to relate surface reflectance spectra to 3D canopy structure and is known as the spectrally-invariant approximation. The proposed approach adapts this technique to the remote sensing of cloud properties such as droplet single scattering albedo and the average number of scatterings (which are the fundamental parameters in radiative transfer theory), with an emphasis on quantifying the associated errors and uncertainties. This retrieval is free from the plane-parallel homogeneous cloud assumption.
clouds↗
Free convection in enclosures exposed to compressive heating
An experimental study of heat transfer in a vertical annulus and a three-dimensional gap used to establish the influence of compressive heating on the convective process in enclosures is presented. Test runs were made using helium gas with compressive rates of 6, 15, and 30 psi/min. Temperature and pressure histories were reduced to film coefficients based on nodal modeling of the test geometries. The data are correlated in terms of free convection parameters. The heat transfer correlations show virtually no influence of compression rate and only a slight dependence on geometry. The correlations will be applied to the design of a vented Galileo mission descent module parachuting into the Jupiter atmosphere.
Bobco, R. P.↗
Transient Numerical Modeling of Catalytic Channels
This paper presents a transient model of catalytic combustion suitable for isolated channels and monolith reactors. The model is a lumped two-phase (gas and solid) model where the gas phase is quasi-steady relative to the transient solid. Axial diffusion is neglected in the gas phase; lateral diffusion, however, is accounted for using transfer coefficients. The solid phase includes axial heat conduction and external heat loss due to convection and radiation. The combustion process utilizes detailed gas and surface reaction models. The gas-phase model becomes a system of stiff ordinary differential equations while the solid phase reduces, after discretization, into a system of stiff ordinary differential-algebraic equations. The time evolution of the system came from alternating integrations of the quasi-steady gas and transient solid. This work outlines the numerical model and presents some sensitivity studies on important parameters including internal transfer coefficients, catalytic surface site density, and external heat-loss (if applicable). The model is compared to two experiments using CO fuel: (1) steady-state conversion through an isothermal platinum (Pt) tube and (2) transient propagation of a catalytic reaction inside a small Pt tube. The model requires internal mass-transfer resistance to match the experiments at lower residence times. Under mass-transport limited conditions, the model reasonably predicted exit conversion using global mass-transfer coefficients. Near light-off, the model results did not match the experiment precisely even after adjustment of mass-transfer coefficients. Agreement improved for the first case after adjusting the surface kinetics such that the net rate of CO adsorption increased compared to O2. The CO / O2 surface mechanism came from a sub-set of reactions in a popular CH4 / O2 mechanism. For the second case, predictions improved for lean conditions with increased external heat loss or adjustment of the kinetics as in the first case. Finally, the results show that different initial surface-species distribution leads to different steady-states under certain conditions. These results demonstrate the utility of a lumped two-phase model of a transient catalytic combustor with detailed chemistry.
Struk, Peter M.↗
Flow Boiling and Condensation Experiment (FBCE): Summary of Findings for Flow Boiling based on Completed ISS Experiments
Since 2011, researchers from Purdue University and NASA Glenn Research Center (GRC) have been collaborating to investigate the effects of gravity on several aspects of flow boiling and flow condensation. This massive research endeavor, termed the Flow Boiling and Condensation Experiment (FBCE), has culminated in development of NASA’s largest and most complex facility for investigation of two-phase fluid physics onboard the ISS. FBCE consists of two separate studies: flow boiling, using the Flow Boiling Module (FBM), and flow condensation, using the Condensation Module for Heat Transfer Measurements (CM-HT); this presentation concerns the FBM portion of FBCE. Fitted with FBM, FBCE was launched to the ISS in August 2021 and experiments were successfully performed starting in February 2022 to amass a large microgravity-flow-boiling database supported by extensive visualization of interfacial behavior using high-speed video. Based on FBCE experiments performed previously in Earth gravity and parabolic flight, along with the new ISS data, several empirical correlations, theoretical models, and CFD models have been developed, enabling the prediction of crucial flow boiling parameters, including heat transfer coefficient and critical heat flux (CHF). These predictive tools, which will be summarized in this presentation, are expected to serve as foundation for design of future space systems involving flow boiling.
Two-phase flow and phase transition↗
Transfer function modeling of damping mechanisms in distributed parameter models
This work formulates a method for the modeling of material damping characteristics in distributed parameter models which may be easily applied to models such as rod, plate, and beam equations. The general linear boundary value vibration equation is modified to incorporate hysteresis effects represented by complex stiffness using the transfer function approach proposed by Golla and Hughes. The governing characteristic equations are decoupled through separation of variables yielding solutions similar to those of undamped classical theory, allowing solution of the steady state as well as transient response. Example problems and solutions are provided demonstrating the similarity of the solutions to those of the classical theories and transient responses of nonviscous systems.
Slater, J. C.↗
Theory of distributed parameter systems
Lumped and distributed parameter systems, discussing transfer matrix elements, connecting lines, etc
Oldenburger, R.↗
Stability conditions for a class of distributed-parameter systems
Distributed parameter systems with transfer function as ratio of output and input multiple transforms, deriving open and closed loop stability criteria
Khatri, H. C.↗
Design of redundant systems
Algorithmic approach is useful for analysis of systems with noisy inputs and when outputs are required in terms of statistical quantities and probabilities of signal excursions beyond desired levels. Procedure can be used with circuits, chemical processes, material design, and other systems with known transfer functions and parameter tolerances.
Doty, L. F.↗
The intensified charge coupled device as a photon counting imager
Actual and projected performance of an intensified charge coupled device (ICCD) to be used as a photon counting imager will be presented. Effects of tube processing on such important CCD parameters as charge transfer efficiency and dark current are discussed.
Williams, J. T.↗
Comparison of LANDSAT-2 and field spectrometer reflectance signatures of south Texas rangeland plant communities
The accuracy was assessed for an atmospheric correction method that depends on clear water bodies to infer solar and atmospheric parameters for radiative transfer equations by measuring the reflectance signature of four prominent south Texas rangeland plants with the LANDSAT satellite multispectral scanner (MSS) and a ground based spectroradiometer. The rangeland plant reflectances produced by the two sensors were correlated with no significant deviation of the slope from unity or of the intercept from zero. These results indicated that the atmospheric correction produced LANDSAT MSS estimates of rangeland plant reflectances that are as accurate as the ground based spectroradiometer.
Richardson, A. J.↗
Evaluation of the potential of one to three SEASAT-SMMR channels in retrieving sea surface temperature
The scanning multichannel microwave radiometer (SMMR) aboard the SEASAT satellite measured emitted radiation in both horizontal and vertical polarizations at microwave frequencies of 6.6, 10.69, 18.0, 21.0 and 37.0 GHz. Retrieval algorithms, for sea surface temperature (SST) determination, from subsets of one to three SMMR channels are obtained by a two step statistical technique. The technique first selects the best subsets of a given size defined by an R2 criterion (coefficient of determination), of a given size by the application of an efficient 'leaps and bounds' technique on a statistical data base. It then performs a regression analysis on the selected subsets. The statistical data base employed a large (600) set of seasonally and geographically diverse atmospheric and surface parameters for radiative transfer calculations. The results of the study of one to three channel subset retrieval algorithms indicate the possibility of using 6.6V, 6.6H and 18V channels for SST determination from SEASAT-SMMR data.
Pandey, P. C.↗
Climate studies with a multilayer energy balance model. III - Climatic impact of stratospheric volcanic aerosols
A multilayer energy balance model is applied in an examination of the sensitivity of climate to stratospheric aerosols induced by volcanic eruptions. Zonally and annually averaged quantities are considered, with ocean and land temperatures computed separately and the atmosphere below the 200 mb level divided into eight layers of 24 sublayers each. The aerosol is assumed to form in the 150-200 mb range. Aerosol parameters for radiative transfer calculations are reflection in the solar spectral region and absorption in the solar and IR regions. A 75 percent aqueous solution of sulfuric acid is assumed for the aerosols. The sensitivity of the hemispherically averaged surface temperature is enhanced 37 percent, with a 20 percent uncertainty, when the thermal IR radiation is excluded. The solar radiation enhances the surface temperatures to a higher degree than the thermal radiation. The maximum response to the evenly distributed aerosols is in the 60-70 deg N latitudes and propagates, weakening, to lower latitudes.
Chou, M.-D.↗
Tethered orbital refueling study
Objectives are to evaluate the feasibility and limitations of fluid acquisition and transfer under an accleration induced in a tethered orbital refueling facility and to provide conceptual designs. Program tasks consist of recommendation of fluid transfer method and parameters; evaluation of disturbances, fluid motion, and damping; selection of passive devices to augment inherent fluid damping and determination of the resultant envelope of operation; assessment of the effect of tether lengths on hazards; and identification of ground and flight tests necessary to prove the tethered orbital refueling concepts.
Fester, D. A.↗