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NASA NTRSDate not supplied

Projecting the Lasting Fate of the Hunga Tonga-Hunga Ha’apai Eruption on the Stratosphere through Connecting Measurements to Models

On 15th Jan. 2022 the submarine volcano Hunga Tonga-Hunga Ha’apai (HTHH) injected approximately 0.5 Tg of sulfur dioxide into the stratosphere, but more significantly added 150-170 Tg of water vapor to the stratospheric background (over a 10% perturbation) in a matter of several hours. The sulfur dioxide rapidly converted to sulfate aerosol and along with water vapor, was transported around the Southern Hemisphere sub-tropics into midlatitudes with some transport into the Northern Hemisphere. With a much longer lifetime than sulfate aerosol, measurable water vapor mass anomalies have persisted with only small losses over the past almost 2 years and are likely to continue above background for the remainder of the decade. Satellite measurements from limb and nadir viewing observing instruments provide the information needed to reasonably initialize the HTHH eruption in the Goddard Earth Observing System (GEOS) model using the “replay” framework coupled to the Global Modeling Initiative (GMI) stratosphere-troposphere chemical mechanism for the recent past and continue the simulations into the future with the free running chemistry climate model (CCM). Using a number of model ensemble members together with the satellite observations, we quantify how the HTHH eruption is perturbing stratospheric composition and climate and projecting the influences to come as the enhanced water vapor continues in the stratosphere with only very slow removal mechanisms. HTHH eruption provides a useful test of chemistry climate models and an opportunity for observation-based process understanding, which we will highlight.

Hunga Tonga-Hunga Ha’apai↗

NASA NTRS2007

Aerosol Source Plume Physical Characteristics from Space-based Multiangle Imaging

Models that assess aerosol effects on regional air quality and global climate parameterize aerosol sources in terms of amount, type, and injection height. The multiangle imaging spectroradiometer (MISR) aboard NASA's Terra satellite retrieves total column aerosol optical thickness (AOT), and aerosol type over cloud-free land and water. A stereo-matching algorithm automatically retrieves reflecting-layer altitude wherever clouds or aerosol plumes have discernable spatial contrast, with about 500-m accuracy, at 1.1-km horizontal resolution. Near-source biomass burning smoke, volcanic effluent, and desert dust plumes are observed routinely, providing information about aerosol amount, particle type, and injection height useful for modeling applications. Compared to background aerosols, the plumes sampled have higher AOT, contain particles having expected differences in Angstrom exponent, size, single-scattering albedo, and for volcanic plume and dust cloud cases, particle shape. As basic thermodynamics predicts, thin aerosol plumes lifted only by regional winds or less intense heat sources are confined to the boundary layer. However, when sources have sufficient buoyancy, the representative plumes studied tend to concentrate within discrete, high-elevation layers of local stability; the aerosol is not uniformly distributed up to a peak altitude, as is sometimes assumed in modeling. MISR-derived plume heights, along with meteorological profile data from other sources, make it possible to relate radiant energy flux observed by the moderate resolution imaging spectroradiometer (MODIS), also aboard the Terra spacecraft, to convective heat flux that plays a major role in buoyant plume dynamics. A MISR climatology of plume behavior based on these results is being developed.

aerosol plumes↗

NASA NTRSDate not supplied

The Spacecraft Water Impurity Monitor, a Framework for the Next Generation Complete Water Analysis System for Crewed Vehicles Beyond the ISS

The Spacecraft Water Impurity Monitor (SWIM) is a joint collaboration to develop an instrument platform that will perform in-flight measurements and deliver a more complete picture of water quality to decision makers. Eventually, missions to the moon, Mars, and beyond will be equipped with analytical capabilities equaling those found in terrestrial labs. Based on what we know about current and future spacecraft environments, SWIM will seek to provide enhanced analytical capability that enables NASA to confidently send astronauts on distant missions without the possibility of returned water samples. This paper discusses the challenges presented by exploration requirements and the research and development progress toward the goal of a total water analysis system. For organic analysis, one of the analysis technologies that the SWIM team have been developing is a liquid-injection gas chromatograph mass spectrometer system; these systems are the workhorses of analytical chemistry laboratories world-wide. For inorganic analysis, the team is exploring a number of technologies ranging from traditional liquid chromatography technologies (e.g. ion chromatography, capillary electrophoresis) to flight-heritage technology such as ion-specific electrodes.

water monitoring↗

NASA NTRS1971

Jet-noise reduction through liquid-base foam injection.

An experimental investigation has been made of the sound-absorbing properties of liquid-base foams and of their ability to reduce jet noise. Protein, detergent, and polymer foaming agents were used in water solutions. A method of foam generation was developed to permit systematic variation of the foam density. The investigation included measurements of sound-absorption coefficents for both plane normal incidence waves and diffuse sound fields. The intrinsic acoustic properties of foam, e.g., the characteristic impedance and the propagation constant, were also determined. The sound emitted by a 1-in.-diam cold nitrogen jet was measured for subsonic (300 m/sec) and supersonic (422 m/sec) jets, with and without foam injection. Noise reductions up to 10 PNdB were measured.

Manson, L.↗

NASA NTRS1999

Experimental Investigation of Pool Boiling Heat Transfer Enhancement in Microgravity in the Presence of Electric Fields

In boiling high heat fluxes are possible driven by relatively small temperature differences, which make its use increasingly attractive in aerospace applications. The objective of the research is to develop ways to overcome specific problems associated with boiling in the low gravity environment by substituting the buoyancy force with the electric force to enhance bubble removal from the heated surface. Previous studies indicate that in terrestrial applications nucleate boiling heat transfer can be increased by a factor of 50, as compared to values obtained for the same system without electric fields. The goal of our research is to experimentally explore the mechanisms responsible for EHD heat transfer enhancement in boiling in low gravity conditions, by visualizing the temperature distributions in the vicinity of the heated surface and around the bubble during boiling using real-time holographic interferometry (HI) combined with high-speed cinematography. In the first phase of the project the influence of the electric field on a single bubble is investigated. Pool boiling is simulated by injecting a single bubble through a nozzle into the subcooled liquid or into the thermal boundary layer developed along the flat heater surface. Since the exact location of bubble formation is known, the optical equipment can be aligned and focused accurately, which is an essential requirement for precision measurements of bubble shape, size and deformation, as well as the visualization of temperature fields by HI. The size of the bubble and the frequency of bubble departure can be controlled by suitable selection of nozzle diameter and mass flow rate of vapor. In this approach effects due to the presence of the electric field can be separated from effects caused by the temperature gradients in the thermal boundary layer. The influence of the thermal boundary layer can be investigated after activating the heater at a later stage of the research. For the visualization experiments a test cell was developed. All four vertical walls of the test cell are transparent, and they allow transillumination with laser light for visualization experiments by HI. The bottom electrode is a copper cylinder, which is electrically grounded. The copper block is heated with a resistive heater and it is equipped with 6 thermocouples that provide reference temperatures for the measurements with HI. The top electrode is a mesh electrode. Bubbles are injected with a syringe into the test cell through the bottom electrode. The working fluids presently used in the interferometric visualization experiments, water and PF 5052, satisfy requirements regarding thermophysical, optical and electrical properties. A 30kV power supply equipped with a voltmeter allows to apply the electric field to the electrodes during the experiments. The magnitude of the applied voltage can be adjusted either manually or through the LabVIEW data acquisition and control system connected to a PC. Temperatures of the heated block are recorded using type-T thermocouples, whose output is read by a data acquisition system. Images of the bubbles are recorded with 35mm photographic and 16mm high-speed cameras, scanned and analyzed using various software packages. Visualized temperature fields HI allows the visualization of temperature fields in the vicinity of bubbles during boiling in the form of fringes. Typical visualized temperature distributions around the air bubbles injected into the thermal boundary layer in PF5052 are shown. The temperature of the heated surface is 35 C. The temperature difference for a pair of fringes is approximately 0.05 C. The heat flux applied to the bottom surface is moderate, and the fringe patterns are regular. In the image a bubble penetrating the thermal boundary layer is visible. Because of the axial symmetry of the problem, simplified reconstruction techniques can be applied to recover the temperature field. The thermal plume developing above the heated surface for more intensive heating is shown. The temperature distribution in the liquid is clearly 3D, and tomographic techniques have to be applied to recover the temperature distribution in such a physical situation. A sequence of interferometric images showing the temperature distribution around the rising bubble, recorded with a high-speed camera is shown. Again, the temperature distribution is 3D, and a more complex approach to the evaluation, the tomographic reconstruction has to be taken. Measurement of the temperature distribution from the fringe pattern temperature distributions that yield important information regarding heat transfer are determined. Two algorithms that allow the quantitative evaluation of interferometric fringe patterns and the reconstruction of temperature fields during boiling have been developed at the Heat Transfer Laboratory of the Johns Hopkins University. In the first algorithm the bubble is assumed to be axially symmetrical, which significantly reduces the computational effort for quantifying the temperature distribution around the bubble. For this purpose the thermal boundary layer around the bubble is divided into equidistant concentric shells, and the refractive index is assumed to be constant in each of the shells. Since large temperature gradients are expected in the vicinity of the bubble during boiling, the deflection of the light beam cannot be neglected in boiling experiments. Since the exit angle of the light beam is known, this allows to account for the deflections and phase shifts outside the boundary layer (in the bulk fluid and in the windows of the test cell). Three dimensional temperature distributions in the vicinity of the bubble are reconstructed using tomographic techniques. In tomography, the measurement volume is sliced into 2D planes. In the present study these planes are parallel to the heated surface. The objective is to determine the values of the field parameter of interest in form of the field function in these 2D planes. The field parameter is the change of the refractive index of the liquid in the measurement volume caused by temperature changes. By superimposing data for many 2D planes recorded at the same time instant, the 3D temperature distribution in the measurement volume is recovered.

Herman, Cila↗

NASA NTRS1999

Bubble Generation in a Continuous Liquid Flow Under Reduced Gravity Conditions

The present work reports a study of bubble generation under reduced gravity conditions for both co-flow and cross-flow configurations. Experiments were performed aboard the DC-9 Reduced Gravity Aircraft at NASA Glenn Research Center, using an air-water system. Three different flow tube diameters were used: 1.27, 1.9, and 2.54 cm. Two different ratios of air injection nozzle to tube diameters were considered: 0.1 and 0.2. Gas and liquid volumetric flow rates were varied from 10 to 200 ml/s. It was experimentally observed that with increasing superficial liquid velocity, the bubbles generated decreased in size. The bubble diameter was shown to increase with increasing air injection nozzle diameters. As the tube diameter was increased, the size of the detached bubbles increased. Likewise, as the superficial liquid velocity was increased, the frequency of bubble formation increased and thus the time to detach forming bubbles decreased. Independent of the flow configuration (for either single nozzle or multiple nozzle gas injection), void fraction and hence flow regime transition can be controlled in a somewhat precise manner by solely varying the gas and liquid volumetric flow rates. On the other hand, it is observed that uniformity of bubble size can be controlled more accurately by using single nozzle gas injection than by using multiple port injection, since this latter system gives rise to unpredictable coalescence of adjacent bubbles. A theoretical model, based on an overall force balance, is employed to study single bubble generation in the dynamic and bubbly flow regime. Under conditions of reduced gravity, the gas momentum flux enhances bubble detachment; however, the surface tension forces at the nozzle tip inhibits bubble detachment. Liquid drag and inertia can act either as attaching or detaching force, depending on the relative velocity of the bubble with respect to the surrounding liquid. Predictions of the theoretical model compare well with performed experiments. However, at higher superficial,liquid velocities, the bubble neck length begins to significantly deviate from the value of the air injection nozzle diameter and thus the theory no longer predicts the experiment behavior. Effects of fluid properties, injection geometry and flow conditions on generated bubble size are investigated using the theoretical model. It is shown that bubble diameter is larger in a reduced gravity environment than in a normal gravity environment at similar flow condition and flow geometry.

Pais, Salvatore Cezar↗

NASA NTRS1974

Reduction of electron density in a plasma by injection of liquids

In this paper, the authors have investigated the physics of various processes relevant to the reduction of electron density in a plasma by addition of water droplets; two processes have in particular been analyzed in some detail, viz, the electron attachment to charged dielectric droplets and the emission of negative ions by vaporization from these droplets. The results of these analyses have been applied to a study of the kinetics of reduction of electron density and charging of droplets in an initially overionized plasma, after addition of water droplets. A number of simplifying assumptions including uniform size and charge on droplets and negligible change in the radius of the droplet due to evaporation have been made.

Sodha, M. S.↗

NASA NTRS1973

The catalytic removal of ammonia and nitrogen oxides from spacecabin atmospheres

Investigations were made on methods for the removal of ammonia and to a lesser extent nitrogen oxides in low concentrations from air. The catalytic oxidation of ammonia was studied over a temperature range of 250 F to 600 F and a concentration range 20 ppm to 500 ppm. Of the catalysts studied, 0.5 percent ruthenium supported on alumina was found to be superior. This material is active at temperatures as low as 250 F and was found to produce much less nitrous oxide than the other two active catalysts, platinum on alumina and Hopcalite. A quantitative design model was developed which will permit the performance of an oxidizer to be calculated. The ruthenium was found to be relatively insensitive to low concentrations of water and to oxygen concentration between 21 percent and 100 percent. Hydrogen sulfide was found to be a poison when injected in relatively large quantities. The adsorption of ammonia by copper sulfate treated silica gel was investigated at temperatures of 72 F and 100 F. A quantitative model was developed for predicting adsorption bed behavior.

Gully, A. J.↗

NASA NTRS2002

Performance of a Model Rich Burn-quick Mix-lean Burn Combustor at Elevated Temperature and Pressure

As interest in pollutant emission from stationary and aero-engine gas turbines increases, combustor engineers must consider various configurations. One configuration of increasing interest is the staged, rich burn - quick mix - lean burn (RQL) combustor. This report summarizes an investigation conducted in a recently developed high pressure gas turbine combustor facility. The model RQL combustor was plenum fed and modular in design. The fuel used for this study is Jet-A which was injected from a simplex atomizer. Emission (CO2, CO, O2, UHC, NOx) measurements were obtained using a stationary exit plane water-cooled probe and a traversing water-cooled probe which sampled from the rich zone exit and the lean zone entrance. The RQL combustor was operated at inlet temperatures ranging from 367 to 700 K, pressures ranging from 200 to 1000 kPa, and combustor reference velocities ranging from 10 to 20 m/s. Variations were also made in the rich zone and lean zone equivalence ratios. Several significant trends were observed. NOx production increased with reaction temperature, lean zone equivalence ratio and residence time and decreased with increased rich zone equivalence ratio. NOx production in the model RQL combustor increased to the 0.4 power with increased pressure. This correlation, compared to those obtained for non-staged combustors (0.5 to 0.7), suggests a reduced dependence on NOx on pressure for staged combustors. Emissions profiles suggest that rich zone mixing is not uniform and that the rich zone contributes on the order of 16 percent to the total NOx produced.

Peterson, Christopher O.↗

NASA NTRSDate not supplied

Cloud Uniformity Measurement from NASA's 2nd Fundamental Ice Crystal Icing Test Part 1 (Water Content & PSD)

This paper presents water content and particle measurements from the second Fundamental Ice Crystal Icing Physics test conducted in the NASA Propulsion Systems Laboratory. The water content measurements came from the Science Engineering Associates Multi-Element Probe and the Isokinetic Probe whereas the Artium Technologies, Inc. Phase Doppler Interferometer and High Speed Imaging instruments measured the particle size distribution. Ice particle accretion due to the ingestion of ice-crystals is attributed to numerous jet engine powerloss events. The NASA PSL is an altitude jet-engine test facility which has recently added a capability to inject ice particles into the flow. This work focuses on characterizing the icing cloud by traversing the instruments across the test section at four different conditions where velocity and water content were varied. For this test, the nozzle patterns were selected to make a uniform cloud in the center 6-inch diameter of the test section. Radial trends for the ice and water content measurements are presented and the melt ratio is calculated at the measurement locations. Particle size distributions are also presented. The measured water content, melt ratio, and particle size decreased moving out radially. Measured water content trends show uniformity to within 19.2% for the center 6 inches of the cloud, as intended. In addition, the total water content increased at centerline with velocity, whereas the melt ratio decreased.

Ice-Crystal Icing↗

NASA NTRSDate not supplied

Cloud Uniformity Measurements from NASA's 2nd Fundamental Ice Crystal Icing Test Part 1 (Water Content & PSD)

Ice-Crystal Icing↗

NASA NTRS1990

Pressure and current balance conditions during electron beam injections from spacecraft

Electrostatic charging level of a conducting surface in response to injections of electron beams into space plasma is investigated by means of one-dimensional Vlasov code. Injections of Maxwellian beams into a vacuum shows that the surface can charge up to an electric potential phi sub s greater than W sub b, where W sub b is the average electron beam energy. Since Maxwellian beams have extended trails with electrons having energies greater than W sub b, it is difficult to quantify the charging level in terms of the energies of the injected electrons. In order to quantitatively understand the charging in excess of W sub b, simulations were carried out for water-bag types of beam with velocity distribution functions described by f(V) = A for V sub min approx. less than V approx. less than V sub max and f(V) = O otherwise, where A is a constant making the normalized beam density unity. It is found that V sub max does not directly determine the charging level. The pressure distribution in the electron sheath determines the electric field distribution near the surface. The electric field in turn determines the electrostatic potential of the vehicle. The pressure distribution is determined by the beam parameters such as the average beam velocity and the velocity spread of the beam.

Hwang, K. S.↗

NASA NTRS2004

Method for removal of nitrogen oxides from stationary combustion sources

A method for removing NO.sub.X from gas streams emanating from stationary combustion sources and manufacturing plants utilizes the injection of hydrogen peroxide into the gas stream for rapid gas-phase oxidation of NO to NO.sub.2 and water-soluble nitrogen acids HNO.sub.2 and HNO.sub.3. The nitrogen acids may be removed from the oxidized gas stream by wet scrubbing or by contact with a particulate alkaline material to form a nitrite/nitrate salt.

Cooper, Charles D.↗

NASA NTRS1973

Analytical and experimental study of supersonic combustion of hydrogen in a vitiated airstream

Detailed probe measurements of total temperature, pressure, and composition were taken in a two-dimensional test section 35.6 cm downstream of hydrogen injection. A high pressure gas generator supplied Mach 2.44 vitiated air or inert gas at elevated temperatures and at a static pressure equal to that of the hydrogen. Special water-cooled probes and sampling techniques were developed for the short test times required by heat-sink hardware. Independent methods of measuring stream total temperatures are compared. For the pure mixing case, the computed composition profile agreed well with the experimental profile. The analysis takes into account the wall boundary layer and the initial boundary layer in the main stream. Ignition of hydrogen, as determined from photographic exposures of the radiating gases, varied from 30 to 10 cm downstream from injection for a 45 K increase in local free-stream static temperature.

Burrows, M. C.↗

NASA NTRS1974

Unified method for serial study of body fluid compartments

Methods for the simultaneous determination of equilibrium space of I-125/RISA(radio-iodinated serum albumin) (plasma volume), Cr-51 red cell mass, Br-82 space (extracellular fluid volume), and tritiated water space (total body water) are described. Determinations were made on two occasions separated by a 1 week interval in 43 healthy young men who were on a strict metabolic diet. Hourly samples were taken for 6 hours after injection of the radionuclides. Correlation of these values to the inscribed exponential disappearance curve was high. In 15 subjects, earlier and more-frequent sampling led to no improvement in the accuracy of estimation of the I-125/RISA space. Use of this method gave results in 12 subjects for Br-82 space and in 11 subjects for tritiated water space which were not significantly different from those obtained by correction for urine loss.

Spears, C. P.↗

NASA NTRS1981

Fluidized bed coal combustion reactor

A fluidized bed coal reactor includes a combination nozzle-injector ash-removal unit formed by a grid of closely spaced open channels, each containing a worm screw conveyor, which function as continuous ash removal troughs. A pressurized air-coal mixture is introduced below the unit and is injected through the elongated nozzles formed by the spaces between the channels. The ash build-up in the troughs protects the worm screw conveyors as does the cooling action of the injected mixture. The ash layer and the pressure from the injectors support a fluidized flame combustion zone above the grid which heats water in boiler tubes disposed within and/or above the combustion zone and/or within the walls of the reactor.

Moynihan, P. I.↗

NASA NTRS1992

Plasma-neutral interaction processes in the magnetosphere of Saturn

Models of Saturnian magnetospheric processes are reviewed emphasizing the interaction of charged and neutral particles in the gaseous phase and mentioning the role of solid matter. It is found that interpretations of different Voyager datasets regarding the Saturnian magnetosphere can vary. Specific interactions examined to resolve these discrepancies include charge exchange, ion-atom interchange, isotropizing and thermalizing collisions, and interactions between magnetospheric charged particles and surface layers of the icy satellites. The latter interactions result in sputtering of the surface or atmosphere as well as neutral injections into the magnetosphere. Constraints based on known reaction rates are shown to be useful in analyzing the abundances of the water-group molecules. The composition of the magnetospheric plasma is shown to be related to the differences between the interactions of atomic and molecular plasmas with neutral matter.

Eviatar, Aharon↗

NASA NTRS1992

Characterization of a Nd:YAG doubled pulsed laser system

A description of a frequency doubled, double pulsed Nd:YAG laser that is to be used to pump an injection locked Ti:Sapphire power oscillator is presented. These two lasers make up the transmitter portion of the Lidar Atmospheric Sensing Experiment (LAWSE) instrument. LASE is a Lidar/DIAL experiment that is to measure water vapor in the troposphere. By utilizing the twin concept, both pulses can be produced with a single laser system, thereby minimizing cost, size, and weight. Alignment problems associated with having two separate lasers each produce one of the twin pulses are also alleviated. The LASE transmitter consists of a doubled pulsed Nd:YAG laser that will pump a Ti:Sapphire power oscillator that will be injection-locked by a diode laser. The wavelength of the Ti:Sapphire output will be tunable from 813 to 818 nm. A performance summary of the pump laser is given. The data verify that the pump laser can meet the performance requirements to pump the Ti:Sapphire power oscillator.

Williams-Byrd, Julie A.↗