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NASA NTRS1996

Spray Combustion Modeling with VOF and Finite-Rate Chemistry

A spray atomization and combustion model is developed based on the volume-of-fluid (VOF) transport equation with finite-rate chemistry model. The gas-liquid interface mass, momentum and energy conservation laws are modeled by continuum surface force mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed range flows. The objectives of the present study are: (1) to develop and verify the fractional volume-of-fluid (VOF) cell partitioning approach into a predictor-corrector algorithm to deal with multiphase (gas-liquid) free surface flow problems; (2) to implement the developed unified algorithm in a general purpose computational fluid dynamics (CFD) code, Finite Difference Navier-Stokes (FDNS), with droplet dynamics and finite-rate chemistry models; and (3) to demonstrate the effectiveness of the present approach by simulating benchmark problems of jet breakup/spray atomization and combustion. Modeling multiphase fluid flows poses a significant challenge because a required boundary must be applied to a transient, irregular surface that is discontinuous, and the flow regimes considered can range from incompressible to highspeed compressible flows. The flow-process modeling is further complicated by surface tension, interfacial heat and mass transfer, spray formation and turbulence, and their interactions. The major contribution of the present method is to combine the novel feature of the Volume of Fluid (VOF) method and the Eulerian/Lagrangian method into a unified algorithm for efficient noniterative, time-accurate calculations of multiphase free surface flows valid at all speeds. The proposed method reformulated the VOF equation to strongly couple two distinct phases (liquid and gas), and tracks droplets on a Lagrangian frame when spray model is required, using a unified predictor-corrector technique to account for the non-linear linkages through the convective contributions of VOF. The discontinuities within the sharp interface will be modeled as a volume force to avoid stiffness. Formations of droplets, tracking of droplet dynamics and modeling of the droplet breakup/evaporation, are handled through the same unified predictor-corrector procedure. Thus the new algorithm is non-iterative and is flexible for general geometries with arbitrarily complex topology in free surfaces. The FDNS finite-difference Navier-Stokes code is employed as the baseline of the current development. Benchmark test cases of shear coaxial LOX/H2 liquid jet with atomization/combustion and impinging jet test cases are investigated in the present work. Preliminary data comparisons show good qualitative agreement between data and the present analysis. It is indicative from these results that the present method has great potential to become a general engineering design analysis and diagnostics tool for problems involving spray combustion.

Chen, Yen-Sen↗

NASA NTRS2015

Scale Model Acoustic Test Validation of IOP-SS Water Prediction using Loci-STREAM-VoF

The Scale Model Acoustic Test (SMAT) is a 5% scale test of the Space Launch System (SLS), which is currently being designed at Marshall Space Flight Center (MSFC). SMAT consists of a 5% scale representation of the ignition overpressure sound-suppression system (IOP-SS) that is being tested to quantify the water flow and induced air entrainment in and around the mobile launcher exhaust hole. This data will be compared with computational fluid dynamics (CFD) simulations using the newly developed Loci-STREAM Volume of Fluid (VoF) methods. Compressible and incompressible VoF methods have been formulated, and are currently being used to simulate the water flow of SMAT IOP-SS. The test data will be used to qualitatively and quantitatively assess and validate the VoF methods.

Nielsen, Tanner↗

DOE OSTI2024

Capturing thin structures in VOF simulations with two-plane reconstruction

A novel interface reconstruction strategy for volume of fluid (VOF) methods is introduced that represents the liquid-gas interface as two planes that co-exist within a single computational cell. In comparison to the piecewise linear interface calculation (PLIC), this new algorithm greatly improves the accuracy of the reconstruction, in particular when dealing with thin structures such as films. The placement of the two planes requires the solution of a non-linear optimization problem in six dimensions, which has the potential to be overly expensive. Further, an efficient solution to this optimization problem is presented here that exploits two key ideas: an algorithm for extracting multiple plane orientations from transported surface data, and an efficient and mass-conserving distance-finding algorithm that accounts for two planes with arbitrary orientation. Additionally, a simple and robust strategy is presented to accurately represent the surface tension forces produced at the interface of subgrid-thickness films. The performance of this new VOF reconstruction is demonstrated on several test cases that illustrate the capability to handle arbitrarily thin films.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRS1995

Numerical modeling of spray combustion with an advanced VOF method

This paper summarizes the technical development and validation of a multiphase computational fluid dynamics (CFD) numerical method using the volume-of-fluid (VOF) model and a Lagrangian tracking model which can be employed to analyze general multiphase flow problems with free surface mechanism. The gas-liquid interface mass, momentum and energy conservation relationships are modeled by continuum surface mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed flow regimes. The objectives of the present study are to develop and verify the fractional volume-of-fluid cell partitioning approach into a predictor-corrector algorithm and to demonstrate the effectiveness of the present approach by simulating benchmark problems including laminar impinging jets, shear coaxial jet atomization and shear coaxial spray combustion flows.

Chen, Yen-Sen↗

NASA NTRS1994

Atomization simulations using an Eulerian-VOF-Lagrangian method

This paper summarizes the technical development and validation of a multiphase computational fluid dynamics (CFD) numerical method using the volume-of-fluid (VOF) model and a Lagrangian tracking model which can be employed to analyze general multiphase flow problems with free surface mechanism. The gas-liquid interface mass, momentum and energy conservations are modeled by continuum surface mechanisms. A new solution method is developed such that the present VOF model can be applied for all-speed flow regimes. The objectives of the present study are to develop and verify the fractional volume-of-fluid cell partitioning approach into a predictor-corrector algorithm and to demonstrate the effectiveness of the present innovative approach by simulating benchmark problems including the coaxial jet atomization.

Chen, Yen-Sen↗

NASA NTRSDate not supplied

Launching Liquid Slugs Through Tube Networks: Investigating Multiphase Liquid Slug Acceleration Behaviors in Spacecraft Propulsion Systems using 3D Multiphase VOF CFD Simulations and High-Speed Flow-Visualization Validation Experiments

Propellant management in spacecraft propulsion systems is complex. In many current and future crewed and robotic spacecraft propulsion systems, a number of unintended or unavoidable scenarios can occasionally lead to liquid “slugs” of propellant accumulating in unwanted locations and thereafter being rapidly accelerated through complex and arbitrary tubing networks otherwise filled with vapor or gas. To develop better understanding of the multiphase fluid dynamics associated with these “slug launch” scenarios, NASA Marshal Space Flight Center’s (MSFC) ER42 branch – the propulsion fluid dynamics research branch – conducted 3D multiphase transient Volume of Fluid (VOF) CFD simulations using an in-house tool called LOCI-Stream VOF on semi-canonical tube networks with straight sections, bends, and bend complexes. In addition, high-speed flow visualization validation experiments using propellants were conducted on similar tube network geometries at the NASA White Sands Test Facility (WSTF). These simulations and flow-visualization experiments found these scenarios lead to a variety of unique multiphase fluid dynamic effects involving the leading and trailing edges of the slug in both straight sections and curved bends as well as the progressive erosion, acceleration, and eventual “punch-through” of the driving gas through the liquid slug. Understanding these multiphase fluid dynamic effects has led to unique and often counter-intuitive observations which have been of critical relevance to important engineering concerns associated with these “slug launch” scenarios.

Multiphase Fluid Dynamics↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is zeta iron carbide-derived structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 46–57°. There is one shorter (1.94 Å) and two longer (2.00 Å) V–O bond length. There are a spread of V–F bond distances ranging from 2.07–2.17 Å. In the second V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 43–55°. There is one shorter (1.93 Å) and two longer (2.02 Å) V–O bond length. There are a spread of V–F bond distances ranging from 2.04–2.13 Å. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a 3-coordinate geometry to three V3+ atoms. There are two inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are five inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–52°. There is one shorter (1.93 Å) and one longer (1.94 Å) V–O bond length. All V–F bond lengths are 2.07 Å. In the second V3+ site, V3+ is bonded to four equivalent O2- and two equivalent F1- atoms to form VO4F2 octahedra that share corners with eight equivalent VO3F3 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 48–50°. All V–O bond lengths are 2.02 Å. Both V–F bond lengths are 2.09 Å. In the third V3+ site, V3+ is bonded to two equivalent O2- and four equivalent F1- atoms to form VO2F4 octahedra that share corners with eight equivalent VO4F2 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. Both V–O bond lengths are 1.94 Å. All V–F bond lengths are 2.06 Å. In the fourth V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 48–52°. There is one shorter (1.89 Å) and two longer (1.97 Å) V–O bond length. There are two shorter (2.12 Å) and one longer (2.21 Å) V–F bond lengths. In the fifth V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. All V–O bond lengths are 2.02 Å. There are one shorter (2.12 Å) and one longer (2.13 Å) V–F bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are three inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of corner and edge-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 48–52°. There is one shorter (1.93 Å) and two longer (1.99 Å) V–O bond length. There are a spread of V–F bond distances ranging from 2.10–2.15 Å. In the second V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of corner and edge-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There are a spread of V–O bond distances ranging from 1.92–2.00 Å. There are a spread of V–F bond distances ranging from 2.10–2.14 Å. In the third V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of corner and edge-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There is one shorter (1.91 Å) and two longer (1.97 Å) V–O bond length. There are a spread of V–F bond distances ranging from 2.13–2.15 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the orthorhombic Ama2 space group. The structure is three-dimensional. there are three inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 48–52°. There is one shorter (1.93 Å) and two longer (1.99 Å) V–O bond length. There are two shorter (2.10 Å) and one longer (2.14 Å) V–F bond lengths. In the second V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There is one shorter (1.92 Å) and two longer (1.98 Å) V–O bond length. There are one shorter (2.13 Å) and two longer (2.14 Å) V–F bond lengths. In the third V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–54°. There are a spread of V–O bond distances ranging from 1.92–2.00 Å. There are a spread of V–F bond distances ranging from 2.10–2.15 Å. There are three inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are three inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the monoclinic P2/m space group. The structure is three-dimensional. there are five inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–52°. There is one shorter (1.89 Å) and two longer (1.98 Å) V–O bond length. There are two shorter (2.13 Å) and one longer (2.17 Å) V–F bond lengths. In the second V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. Both V–O bond lengths are 1.93 Å. All V–F bond lengths are 2.07 Å. In the third V3+ site, V3+ is bonded to two equivalent O2- and four equivalent F1- atoms to form VO2F4 octahedra that share corners with eight equivalent VO3F3 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–52°. Both V–O bond lengths are 1.94 Å. All V–F bond lengths are 2.07 Å. In the fourth V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–50°. There are two shorter (2.01 Å) and two longer (2.02 Å) V–O bond lengths. There are one shorter (2.10 Å) and one longer (2.14 Å) V–F bond lengths. In the fifth V3+ site, V3+ is bonded to four equivalent O2- and two equivalent F1- atoms to form VO4F2 octahedra that share corners with eight equivalent VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. All V–O bond lengths are 2.01 Å. Both V–F bond lengths are 2.13 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are eight inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. There is one shorter (1.93 Å) and one longer (1.94 Å) V–O bond length. There are two shorter (2.06 Å) and two longer (2.07 Å) V–F bond lengths. In the second V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–51°. There is one shorter (1.89 Å) and two longer (1.98 Å) V–O bond length. There are one shorter (2.11 Å) and two longer (2.13 Å) V–F bond lengths. In the third V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. There is one shorter (1.93 Å) and one longer (1.94 Å) V–O bond length. All V–F bond lengths are 2.06 Å. In the fourth V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 48–52°. There is one shorter (1.92 Å) and one longer (1.94 Å) V–O bond length. There are two shorter (2.07 Å) and two longer (2.08 Å) V–F bond lengths. In the fifth V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–51°. All V–O bond lengths are 2.01 Å. There are one shorter (2.12 Å) and one longer (2.14 Å) V–F bond lengths. In the sixth V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of corner and edge-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–52°. There is one shorter (1.90 Å) and two longer (1.97 Å) V–O bond length. There are two shorter (2.12 Å) and one longer (2.22 Å) V–F bond lengths. In the seventh V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. There are two shorter (2.01 Å) and two longer (2.02 Å) V–O bond lengths. Both V–F bond lengths are 2.12 Å. In the eighth V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 48–50°. There are two shorter (2.01 Å) and two longer (2.02 Å) V–O bond lengths. There are one shorter (2.12 Å) and one longer (2.13 Å) V–F bond lengths. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the sixth F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the seventh F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the eighth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. there are eight inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–52°. There is one shorter (1.89 Å) and two longer (1.97 Å) V–O bond length. There are two shorter (2.13 Å) and one longer (2.16 Å) V–F bond lengths. In the second V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–50°. All V–O bond lengths are 2.02 Å. There are one shorter (2.09 Å) and one longer (2.13 Å) V–F bond lengths. In the third V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. Both V–O bond lengths are 1.93 Å. All V–F bond lengths are 2.06 Å. In the fourth V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–52°. Both V–O bond lengths are 1.93 Å. There are two shorter (2.06 Å) and two longer (2.07 Å) V–F bond lengths. In the fifth V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–52°. There is one shorter (1.93 Å) and one longer (1.94 Å) V–O bond length. There are two shorter (2.06 Å) and two longer (2.07 Å) V–F bond lengths. In the sixth V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO4F2 octahedra and edges with two equivalent VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–52°. There is one shorter (1.89 Å) and two longer (1.97 Å) V–O bond length. There are two shorter (2.13 Å) and one longer (2.18 Å) V–F bond lengths. In the seventh V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 47–51°. There are two shorter (2.01 Å) and two longer (2.02 Å) V–O bond lengths. There are one shorter (2.10 Å) and one longer (2.14 Å) V–F bond lengths. In the eighth V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO2F4 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 49–50°. All V–O bond lengths are 2.02 Å. Both V–F bond lengths are 2.12 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fifth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the sixth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the seventh O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the eighth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fifth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the sixth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the seventh F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the eighth F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is beta Vanadium nitride-derived structured and crystallizes in the monoclinic P2_1 space group. The structure is three-dimensional. there are four inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 47–55°. There are a spread of V–O bond distances ranging from 1.93–2.00 Å. There are two shorter (2.09 Å) and one longer (2.16 Å) V–F bond lengths. In the second V3+ site, V3+ is bonded to four O2- and two F1- atoms to form VO4F2 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 49–55°. There are a spread of V–O bond distances ranging from 2.00–2.09 Å. Both V–F bond lengths are 2.09 Å. In the third V3+ site, V3+ is bonded to three O2- and three F1- atoms to form a mixture of edge and corner-sharing VO3F3 octahedra. The corner-sharing octahedra tilt angles range from 45–54°. There are a spread of V–O bond distances ranging from 1.92–2.01 Å. There are two shorter (2.09 Å) and one longer (2.18 Å) V–F bond lengths. In the fourth V3+ site, V3+ is bonded to two O2- and four F1- atoms to form VO2F4 octahedra that share corners with eight VO3F3 octahedra and edges with two equivalent VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 45–51°. There is one shorter (1.95 Å) and one longer (1.98 Å) V–O bond length. There are a spread of V–F bond distances ranging from 1.98–2.08 Å. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

VOF is zeta iron carbide-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are six inequivalent V3+ sites. In the first V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO3F3 octahedra and edges with two VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 45–53°. There are a spread of V–O bond distances ranging from 1.98–2.01 Å. There are a spread of V–F bond distances ranging from 2.03–2.12 Å. In the second V3+ site, V3+ is bonded to four O2- and two equivalent F1- atoms to form a mixture of edge and corner-sharing VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 46–55°. There are two shorter (2.04 Å) and two longer (2.07 Å) V–O bond lengths. Both V–F bond lengths are 2.07 Å. In the third V3+ site, V3+ is bonded to four O2- and two equivalent F1- atoms to form a mixture of edge and corner-sharing VO4F2 octahedra. The corner-sharing octahedra tilt angles range from 46–54°. There are two shorter (1.99 Å) and two longer (2.03 Å) V–O bond lengths. Both V–F bond lengths are 2.11 Å. In the fourth V3+ site, V3+ is bonded to three O2- and three F1- atoms to form VO3F3 octahedra that share corners with eight VO3F3 octahedra and edges with two VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 47–55°. There are a spread of V–O bond distances ranging from 1.96–2.00 Å. There are two shorter (2.08 Å) and one longer (2.13 Å) V–F bond lengths. In the fifth V3+ site, V3+ is bonded to two equivalent O2- and four F1- atoms to form a mixture of edge and corner-sharing VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 46–54°. Both V–O bond lengths are 1.92 Å. All V–F bond lengths are 2.07 Å. In the sixth V3+ site, V3+ is bonded to two equivalent O2- and four F1- atoms to form a mixture of edge and corner-sharing VO2F4 octahedra. The corner-sharing octahedra tilt angles range from 45–54°. Both V–O bond lengths are 1.98 Å. There are two shorter (1.97 Å) and two longer (2.06 Å) V–F bond lengths. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the fourth O2- site, O2- is bonded in a distorted trigonal planar geometry to three V3+ atoms. There are four inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the second F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms. In the third F1- site, F1- is bonded in a 3-coordinate geometry to three V3+ atoms. In the fourth F1- site, F1- is bonded in a distorted trigonal planar geometry to three V3+ atoms.

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

Computed materials data using density functional theory calculations. These calculations determine the electronic structure of bulk materials by solving approximations to the Schrodinger equation. For more information, see https://materialsproject.org/docs/calculations

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

36 MATERIALS SCIENCE↗

DOE OSTI2020

Materials Data on VOF by Materials Project

36 MATERIALS SCIENCE↗