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NASA NTRS2011

Heavy Lift Launch Capability with a New Hydrocarbon Engine

The Advanced Concepts Office at NASA's George C. Marshall Space Flight Center was tasked to define the thrust requirement of a new liquid oxygen rich staged combustion cycle hydrocarbon engine that could be utilized in a launch vehicle to meet NASA s future heavy lift needs. Launch vehicle concepts were sized using this engine for different heavy lift payload classes. Engine out capabilities for one of the heavy lift configurations were also analyzed for increased reliability that may be desired for high value payloads or crewed missions. The applicability for this engine in vehicle concepts to meet military and commercial class payloads comparable to current ELV capability was also evaluated.

Threet, Grady E., Jr.↗

NASA NTRS2011

CFD Study of the Hydrocarbon Boost Low-Pressure Inducer and Kicker in the Presence of a Circumferential Groove

Results are presented of a computational fluid dynamics (CFD) study done in support of Marshall Space Flight Center's (MSFC) sub-scale water flow experiments of the Hydrocarbon Boost (HCB) Oxidizer Turbopump (OTP) being developed by the Air Force Research Laboratory (AFRL) and Aerojet. A circumferential groove may be added to the pump to reduce synchronous cavitation and subsequent bearing loads at a minimal performance cost. However, the energy may reappear as high order cavitation (HOC) that spans a relatively large frequency range. Thus, HOC may have implications for the full-scale OTP inducer in terms of reduced structural margin at higher mode frequencies. Simulations using the LOCI/Stream CFD program were conducted in order to explore the fluid dynamical impact of the groove on the low-pressure inducer and kicker. It was found that the circumferential groove has minimal head performance impact, but causes back-flowing high-swirl fluid to interact with the nearly-axial incoming fluid just above the inducer blades. The high-shear interface between the fluids is Kelvin-Helmholtz unstable, resulting in trains of low pressure regions or 'pearls' forming near the upstream edge of the groove. When the static pressure in these regions becomes low enough and they get cut by the blade leading edge, HOC is thought to occur. Although further work is required, the numerical models indicate that HOC will occur in the runbox of the AFRL/Aerojet HCB OTP. Comparisons to the ongoing water flow experiments will be discussed, as well as possible designs that may mitigate HOC while continuing to reduce synchronous cavitation. December 2011 MSS/LPS/SPS Joint Subcommittee Meeting ABSTRACT SUBMITTAL FORM

Coker, Robert↗

NASA NTRS2013

Thermal Stability of RP-2 for Hydrocarbon Boost Regenerative Cooling

A series of tests were performed in the NASA Glenn Research Centers Heated Tube Facility to study the heat transfer and thermal stability behavior of RP-2 under conditions similar to those found in rocket engine cooling channels. It has long been known that hydrocarbon fuels, such as RP-2, can decompose at high temperature to form deposits (coke) which can adversely impact rocket engine cooling channel performance. The heated tube facility provides a simple means to study these effects. Using resistively heated copper tubes in a vacuum chamber, flowing RP-2 was heated to explore thermal effects at a range of test conditions. Wall temperature (850-1050F) and bulk fluid temperature (300-500F) were varied to define thermal decomposition and stability at each condition. Flow velocity and pressure were fixed at 75 fts and 1000 psia, respectively. Additionally, five different batches of RP-2 were tested at identical conditions to examine any thermal stability differences resulting from batch to batch compositional variation. Among these tests was one with a potential coke reducing additive known as 1,2,3,4-Tetrahydroquinoline (THQ). While copper tubes were used for the majority of tests, two exploratory tests were performed with a copper alloy known as GRCop-42. Each tube was instrumented with 15 thermocouples to examine the temperature profile, and carbon deposition at each thermocouple location was determined post-test in an oxidation furnace. In many tests, intermittent local temperature increases were observed visually and in the thermocouple data. These hot spots did not appear to correspond with a higher carbon deposition.

Kleinhenz, Julie E.↗

NASA NTRS2015

3-D CFD Simulation and Validation of Oxygen-Rich Hydrocarbon Combustion in a Gas-Centered Swirl Coaxial Injector using a Flamelet-Based Approach

Injector design is a critical part of the development of a rocket Thrust Chamber Assembly (TCA). Proper detailed injector design can maximize propulsion efficiency while minimizing the potential for failures in the combustion chamber. Traditional design and analysis methods for hydrocarbon-fuel injector elements are based heavily on empirical data and models developed from heritage hardware tests. Using this limited set of data produces challenges when trying to design a new propulsion system where the operating conditions may greatly differ from heritage applications. Time-accurate, Three-Dimensional (3-D) Computational Fluid Dynamics (CFD) modeling of combusting flows inside of injectors has long been a goal of the fluid analysis group at Marshall Space Flight Center (MSFC) and the larger CFD modeling community. CFD simulation can provide insight into the design and function of an injector that cannot be obtained easily through testing or empirical comparisons to existing hardware. However, the traditional finite-rate chemistry modeling approach utilized to simulate combusting flows for complex fuels, such as Rocket Propellant-2 (RP-2), is prohibitively expensive and time consuming even with a large amount of computational resources. MSFC has been working, in partnership with Streamline Numerics, Inc., to develop a computationally efficient, flamelet-based approach for modeling complex combusting flow applications. In this work, a flamelet modeling approach is used to simulate time-accurate, 3-D, combusting flow inside a single Gas Centered Swirl Coaxial (GCSC) injector using the flow solver, Loci-STREAM. CFD simulations were performed for several different injector geometries. Results of the CFD analysis helped guide the design of the injector from an initial concept to a tested prototype. The results of the CFD analysis are compared to data gathered from several hot-fire, single element injector tests performed in the Air Force Research Lab EC-1 test facility located at Edwards Air Force Base.

Richardson, Brian↗

NASA NTRS2015

Electrode Design for Low Temperature Direct-Hydrocarbon Solid Oxide Fuel Cells

In certain embodiments of the present disclosure, a solid oxide fuel cell is described. The solid oxide fuel cell includes a hierarchically porous cathode support having an impregnated cobaltite cathode deposited thereon, an electrolyte, and an anode support. The anode support includes hydrocarbon oxidation catalyst deposited thereon, wherein the cathode support, electrolyte, and anode support are joined together and wherein the solid oxide fuel cell operates a temperature of 600.degree. C. or less.

Chen, Fanglin↗

NASA NTRS2016

High-Resolution IR Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons: The Realm of Anharmonicity

We report on an experimental and theoretical investigation of the importance of anharmonicity in the 3 micrometers CH stretching region of Polycyclic Aromatic Hydrocarbon (PAH) molecules. We present mass-resolved, high-resolution spectra of the gas-phase cold ((is) approximately 4K) linear PAH molecules naphthalene, anthracene, and tetracene. The measured IR spectra show a surprisingly high number of strong vibrational bands. For naphthalene, the observed bands are well separated and limited by the rotational contour, revealing the band symmetries. Comparisons are made to the harmonic and anharmonic approaches of the widely used Gaussian software. We also present calculated spectra of these acenes using the computational program SPECTRO, providing anharmonic predictions enhanced with a Fermi-resonance treatment that utilizes intensity redistribution. We demonstrate that the anharmonicity of the investigated acenes is strong, dominated by Fermi resonances between the fundamental and double combination modes, with triple combination bands as possible candidates to resolve remaining discrepancies. The anharmonic spectra as calculated with SPECTRO lead to predictions of the main modes that fall within 0.5% of the experimental frequencies. The implications for the Aromatic Infrared Bands, specifically the 3-m band are discussed.

Astrochemistry↗

NASA NTRS2016

Total Hydrocarbon Content (THC) Testing in Liquid Oxygen (LOX)

The measured Total Hydrocarbon Content (THC) levels in liquid oxygen (LOX) systems at Stennis Space Center (SSC) have shown wide variations. Examples of these variations include the following: 1) differences between vendor-supplied THC values and those obtained using standard SSC analysis procedures; and 2) increasing THC values over time at an active SSC test stand in both storage and run vessels. A detailed analysis of LOX sampling techniques, analytical instrumentation, and sampling procedures will be presented. Additional data obtained on LOX system operations and LOX delivery trailer THC values during the past 12-24 months will also be discussed. Field test results showing THC levels and the distribution of the THC's in the test stand run tank, modified for THC analysis via dip tubes, will be presented.

Meneghelli, B. J.↗

NASA NTRS2015

Laser Induced Fluorescence Spectroscopy of Neutral and Ionized Polycyclic Aromatic Hydrocarbons in the Cosmic Simulation Chamber

Polycyclic aromatic hydrocarbon (PAH) molecules are considered the best carriers to account for the ubiquitous infrared emission bands. PAHs have also been proposed as candidates to explain the diffuse interstellar bands (DIBs), a series of absorption features seen on the interstellar extinction curve and are plausible carriers for the extended red emission (ERE), a photoluminescent process associated with a wide variety of interstellar environments. Extensive efforts have been devoted over the past two decades to characterize the physical and chemical properties of PAH molecules and ions in space. Absorption spectra of PAH molecules and ions trapped in solid matrices have been compared to the DIBs. Absorption spectra of several cold, isolated gas-phase PAHs have also been measured under experimental conditions that mimic the interstellar conditions. The purpose of this study is to provide a new dimension to the existing spectroscopic database of neutral and single ionized PAHs that is largely based on absorption spectra by adding emission spectroscopy data. The measurements are based on the laser induced fluorescence (LIF) technique and are performed with the Pulsed Discharge Nozzle (PDN) of the COSmIC laboratory facility at NASA Ames laboratory. The PDN generates a plasma in a free supersonic jet expansion to simulate the physical and the chemical conditions in interstellar environments. We focus, here, on the fluorescence spectra of large neutral PAHs and their cations where there is a lack of fluorescence spectroscopy data. The astronomical implications of the data (e.g., ERE) are examined.

Laboratory↗

NASA NTRS2017

High-Resolution IR Absorption Spectroscopy of Polycyclic Aromatic Hydrocarbons in the 3-micrometers Region: Role of Periphery

In this work we report on high-resolution IR absorption studies that provide a detailed view on how the peripheral structure of irregular polycyclic aromatic hydrocarbons (PAHs) affects the shape and position of their 3-micrometers absorption band. To this purpose we present mass-selected, high-resolution absorption spectra of cold and isolated phenanthrene, pyrene, benz[a]antracene, chrysene, triphenylene, and perylene molecules in the 2950-3150 per cm range. The experimental spectra are compared with standard harmonic calculations, and anharmonic calculations using a modified version of the SPECTRO program that incorporates a Fermi resonance treatment utilizing intensity redistribution. We show that the 3-micrometers region is dominated by the effects of anharmonicity, resulting in many more bands than would have been expected in a purely harmonic approximation. Importantly, we find that anharmonic spectra as calculated by SPECTRO are in good agreement with the experimental spectra. Together with previously reported high-resolution spectra of linear acenes, the present spectra provide us with an extensive dataset of spectra of PAHs with a varying number of aromatic rings, with geometries that range from open to highly-condensed structures, and featuring CH groups in all possible edge configurations. We discuss the astrophysical implications of the comparison of these spectra on the interpretation of the appearance of the aromatic infrared 3-micrometers band, and on features such as the two-component emission character of this band and the 3-micrometers emission plateau.

techniques: spectroscopic↗

NASA NTRS2017

Radiation Processing of Polycyclic Aromatic Hydrocarbons (PAHs) in Space: ICEE PoC

Small Polycyclic Aromatic Hydrocarbon molecules or PAHs (<30 carbon atoms) have been identified in comets, meteorites, asteroids, and interplanetary dust particles in our Solar System, while PAHs in the Interstellar Medium (ISM) tend to be much larger, usually between 50 to 100 carbon atoms in size. The cause of the size disparity between PAHs found in the ISM and Solar System as well as their influence on Solar System organics is not yet understood. Two chemical evolutionary paths have been proposed to explain the inventory of solar system organics. In one the prebiotic material was formed from the radiation induced modification of large pre-solar carbon-bearing species (e.g. ISM PAHs). The second path suggests that Solar System prebiotic matter is the result of bottom-up synthesis from small reactive molecules after the Solar System was formed. In this second scenario very few ISM PAHs survived the harsh pre-solar radiation as aromatic structures. ICEE PoC (ICEE Proof of Concept) investigated factors impacting the chemical evolution of large PAHs irradiated under conditions similar to the proto-solar nebula. Likewise ICEE PoC will refine the technical parameters of the proposed ICEE (Institute for Carbon Evolution Experiment) laboratory.

Mattioda, Andrew↗

NASA NTRS2018

Spatial and Seasonal Variations in C3Hx Hydrocarbon Abundance in Titan's Stratosphere from Cassini CIRS Observations

Of the C3Hx hydrocarbons, propane (C3H8) and propyne (methylacetylene, CH3C2H) were first detected in Titan’s atmosphere during the Voyager 1 flyby in 1980. Propene (propylene, C3H6) was first detected in 2013 with data from the Composite InfraRed Spectrometer (CIRS) instrument on Cassini. We present the first measured abundance profiles of propene on Titan from radiative transfer modeling, and compare our measurements to predictions derived from several photochemical models. Near the equator, propene is observed to have a peak abundance of 10 ppbv at a pressure of 0.2 mbar. Several photochemical models predict the amount at this pressure to be in the range 0.3–1 ppbv and also show a local minimum near 0.2 mbar which we do not see in our measurements. We also see that propene follows a different latitudinal trend than the other C3 molecules. While propane and propyne concentrate near the winter pole, transported via a global convective cell, propene is most abundant above the equator. We retrieve vertical abundances profiles between 125 km and 375 km for these gases for latitude averages between 60°S–20°S, 20°S–20°N, and 20°N–60°N over two time periods, 2004 through 2009 representing Titan’s atmosphere before the 2009 equinox, and 2012 through 2015 representing time after the equinox. Additionally, using newly corrected line data, we determined an updated upper limit for allene (propadiene, CH2CCH2, the isomer of propyne). We claim a 3-σ upper limit mixing ratio of 2.5 × 10(exp −9) within 30° of the equator. The measurements we present will further constrain photochemical models by refining reaction rates and the transport of these gases throughout Titan’s atmosphere.

Lombardo, Nicholas A.↗

NASA NTRS2020

Hydrocarbon Burn Facility SWMU 007 Interim Groundwater Monitoring Report Kennedy Space Center, Florida

This Interim Groundwater Monitoring (IGWM) Report presents the findings of IGWM completed in September 2019 for the Northern Volatile Organic Compound (VOC) Area of the Hydrocarbon Burn Facility (HBF) at Kennedy Space Center (KSC), Florida. The IGWM was implemented for the Northern VOC Area to provide additional data, to be evaluated along with previous long-term monitoring data, to determine future IGWM options and to evaluate the efficacy of monitored natural attenuation (MNA) as a passive remedial measure in comparison to active remedies for the Northern VOC Area. The primary contaminants of concern in the Northern VOC Area are trichloroethene (TCE), cis-1,2-dichloroethene (cDCE), vinyl chloride (VC), and benzene.

groundwater↗

NASA NTRS2020

Characterization of Cosmic Grain Analogs Formed at Low Temperature from Small Hydrocarbon Precursors in the NASA Ames COSmIC Facility

Here, we present the results of the first solid-phase ex situ analysis of cosmic grain analogs produced at low temperature (<200 K) in the NASA Ames COsmic SImulation Chamber (COSmIC) from small hydrocarbon precursors, methane (CH4) and acetylene (C2H2), seeded in an argon supersonic jet expansion and submitted to a plasma discharge. The plasma-induced chemical reactions, initiated between the precursor molecules and their atomic and molecular fragments, radicals and ions, produce larger molecules and eventually solid particles that are collected in situ under controlled conditions. Scanning electron microscopy (SEM) imaging was used to provide insight on the morphology and growth structure of the grains produced in COSmIC, and to investigate how the precursors used to produce the grains affect these parameters. This SEM study has shown that under identical experimental conditions with fixed physical and chemical parameters (precursor density, temperature, energy, and reaction time), heavier precursors in the initial mixture produce larger grains and in larger quantity, most likely as a result of a more complex chemistry: most of the grains produced in the Ar/CH4 (95:5) gas mixture ranged from 15 to 385 nm in diameter with an average density of 2.1 grains per sq.μm, while the grains produced in the Ar/C2H2 (95:5) gas mixture ranged from 40 to 650 nm with a density of 3.5 grains per sq.μm. Changes in the morphology were also observed, with grains produced from acetylene (C2H2) precursors tending to be more spherical than grains produced from methane (CH4) precursors. This change in morphology could be associated with different stages of growth formation at low temperature from a more "planar" growth at first, followed by coagulation into more spherical particles. This study demonstrates that the COSmIC experimental setup can be used to investigate carbon grain formation from small gas-phase molecular precursors at low temperature (<200 K), i.e., under a temperature regime that is representative of the dust condensation zone and outer region of circumstellar envelopes.

Ella Sciamma-O'Brien↗

NASA NTRS2018

Spatial and Seasonal Variations in C3Hx Hydrocarbon Abundance in Titan’s Stratosphere from Cassini CIRS Observations

Of the C3Hx hydrocarbons, propane (C3H8) and propyne (methylacetylene, CH3C2H) were first detected in Titan’s atmosphere during the Voyager 1 flyby in 1980. Propene (propylene, C3H6) was first detected in 2013 with data from the Composite InfraRed Spectrometer (CIRS) instrument on Cassini. We present the first measured abundance profiles of propene on Titan from radiative transfer modeling, and compare our measurements to predictions derived from several photochemical models. Near the equator, propene is observed to have a peak abundance of 10 ppbv at a pressure of 0.2 mbar. Several photochemical models predict the amount at this pressure to be in the range 0.3 - 1 ppbv and also show a local minimum near 0.2 mbar which we do not see in our measurements. We also see that propene follows a different latitudinal trend than the other C3 molecules. While propane and propyne concentrate near the winter pole, transported via a global convective cell, propene is most abundant above the equator. We retrieve vertical abundances profiles between 125 km and 375 km for these gases for latitude averages between 60◦S to 20◦S, 20◦S to 20◦N, and 20◦N to 60◦N over two time periods, 2004 through 2009 representing Titan’s atmosphere before the 2009 equinox, and 2012 through 2015 representing time after the equinox. Additionally, using newly corrected line data, we determined an updated upper limit for allene (propadiene, CH2CCH2), the isomer of propyne). The measurements we present will further constrain photochemical models, by refining reaction rates and the transport of these gases throughout Titan’s atmosphere.

Nicholas A. Lombardo↗

NASA NTRS2021

Hydrocarbon Burn Facility SWMU 007 Interim Groundwater Monitoring Report Kennedy Space Center, Florida

This Interim Groundwater Monitoring (IGWM) Report presents the findings of IGWM activities completed in November/December 2020 for the Volatile Organic Compound (VOC) Area of the Hydrocarbon Burn Facility (HBF) at Kennedy Space Center (KSC), Florida. HBF has been designated as Solid Waste Management Unit 007 under the KSC Resource Conservation and Recovery Act Corrective Action Program.

Jennifer Buel↗

NASA NTRS2022

Hydrocarbon Burn Facility, SWMU 007 PER- and Polyfluoroalkyl Substances (PFAS) Assessment report Addendum Kennedy Space Center, Florida

This document discusses the Per-and Polyfluoroalkyl Substances (PFAS) assessment activities performed from December 2020 through November 2021 at the Hydrocarbon Burn Facility (HBF) located at Kennedy Space Center (KSC), Florida. The HBF site has been designated Solid Waste Management Unit (SWMU) 007 under KSC’s Resource Conservation and Recovery Act (RCRA) Corrective Action Program. This PFAS Assessment Report Addendum (ARA) was prepared by Tetra Tech, Inc., for the National Aeronautics and Space Administration (NASA) under Indefinite Delivery Indefinite Quantity (IDIQ) Contract 80KSC019D0011-80KSC019F0077.

Jennifer M. Buel↗

NASA NTRS2022

Deuterium Isotope Fractionation of Polycyclic Aromatic Hydrocarbons in Meteorites as an Indicator of Interstellar/Protosolar Processing History

The stable isotope composition of soluble and insoluble organic compounds in carbonaceous chondrites can be used to determine the provenance of organic molecules in space. Deuterium enrichment in meteoritic organics could be a residual signal of synthetic reactions occurring in the cold interstellar medium or an indicator of hydrothermal parent-body reactions. δD values have been measured in grains and bulk samples for a wide range of meteorites; however, these reservoirs are highly variable and may have experienced fractionation during thermal and/or aqueous alteration. Among the plethora of organic compounds in meteorites are polycyclic aromatic hydrocarbons (PAHs), which are stable and abundant in carbonaceous chondrites, and their δD ratio may preserve evidence about their formation environment as well as the influence of parent-body processes. This study tests hypotheses about the potential links between PAHs-deuteration concentrations and their formation conditions by examining the δD ratio of PAHs in three CM carbonaceous chondrites representing an aqueous alteration gradient. We use deuterium enrichments in soluble 2–5-ring PAHs as an indicator of either photon-driven deuteration due to unimolecular photodissociation in warm regions of space, gas-phase ion–molecule reactions in cold interstellar regions of space, or UV photolysis in ices. We also test hypothesized reaction pathways during parent-body processing that differ between partially and fully aromatized PAHs. New methodological approaches were developed to extract small, volatile PAHs without fractionation. Our results suggest that meteoritic PAHs could have formed through reactions in cold regions, with possible overprinting of deuterium enrichment during aqueous parent-body alteration, but the data could not rule out PAH alteration in icy mantles as well.

H V Graham↗

NASA NTRS2022

Hydrocarbon Burn Facility SWMU 007 Interim Groundwater Monitoring Report Kennedy Space Center, Florida

This Interim Groundwater Monitoring (IGWM) Report presents the findings of IGWM activities completed in November 2021 along with an October 2021 direct push technology (DPT) investigation to confirm plume stability for the Volatile Organic Compound (VOC) Area of the Hydrocarbon Burn Facility (HBF) at Kennedy Space Center (KSC), Florida. HBF has been designated as Solid Waste Management Unit 007 under the KSC Resource Conservation and Recovery Act Corrective Action Program.

Jennifer Buel↗