The Experts below are selected from a list of 291 Experts worldwide ranked by ideXlab platform
Shixi Zhang - One of the best experts on this subject based on the ideXlab platform.
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experimental and simulation of single equilibrium Stage Separation of methane hydrogen mixtures via forming hydrate
Fluid Phase Equilibria, 2007Co-Authors: Guangjin Chen, Shixi ZhangAbstract:Abstract To separate gas mixture through forming hydrate is a new technology, which might be applicable in recovering economically valuable gas components, such as hydrogen and ethylene from refinery gases. A set of equipment was designed and constructed for the experimental study of gas mixtures Separation efficiency via forming hydrate. Batch operation method with/without gas–liquid circulating can be adopted. The Separation efficiency for hydrogen + methane gas mixtures in pure water, 1, and 6 mol% tetrahydrofuran (THF) in initial aqueous solution were examined at different temperature, pressure, and feed gas composition conditions. The results showed that high operation pressure is needed for Separation from pure water, which is only used to the initial hydrogen enriched. With the existence of THF in aqueous solution, hydrogen was remarkably enriched in vapor phase by a single equilibrium Stage, especially when 6 mol% THF added. Based on the extended Chen-Guo hydrate model, an algorithm for vapor-hydrate flash calculation was developed to simulate the single equilibrium Stage Separation of gas mixtures. Good predict precision can be obtained by the simulating algorithm, which was then extended to simulate the experimental conditions that cannot be achieved by the limit of device.
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Experimental and simulation of single equilibrium Stage Separation of (methane + hydrogen) mixtures via forming hydrate
Fluid Phase Equilibria, 2007Co-Authors: Chang-feng Ma, Guangjin Chen, Shixi ZhangAbstract:Abstract To separate gas mixture through forming hydrate is a new technology, which might be applicable in recovering economically valuable gas components, such as hydrogen and ethylene from refinery gases. A set of equipment was designed and constructed for the experimental study of gas mixtures Separation efficiency via forming hydrate. Batch operation method with/without gas–liquid circulating can be adopted. The Separation efficiency for hydrogen + methane gas mixtures in pure water, 1, and 6 mol% tetrahydrofuran (THF) in initial aqueous solution were examined at different temperature, pressure, and feed gas composition conditions. The results showed that high operation pressure is needed for Separation from pure water, which is only used to the initial hydrogen enriched. With the existence of THF in aqueous solution, hydrogen was remarkably enriched in vapor phase by a single equilibrium Stage, especially when 6 mol% THF added. Based on the extended Chen-Guo hydrate model, an algorithm for vapor-hydrate flash calculation was developed to simulate the single equilibrium Stage Separation of gas mixtures. Good predict precision can be obtained by the simulating algorithm, which was then extended to simulate the experimental conditions that cannot be achieved by the limit of device.
Bandu N Pamadi - One of the best experts on this subject based on the ideXlab platform.
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Overview of Transonic to Hypersonic Stage Separation Tool Development for Multi-Stage-To-Orbit Concepts
2013Co-Authors: Kelly J. Murphy, Bandu N Pamadi, William I. Scallion, Pieter Buning, Kenneth JonesAbstract:An overview of research efforts at NASA in support of the Stage Separation and ascent aerothermodynamics research program is presented. The objective of this work is to develop a synergistic suite of experimental, computational, and engineering tools and methods to apply to vehicle Separation across the transonic to hypersonic speed regimes. Proximity testing of a generic bimese wing-body configuration is on-going in the transonic (Mach numbers 0.6, 1.05, and 1.1), supersonic (Mach numbers 2.3, 3.0, and 4.5) and hypersonic (Mach numbers 6 and 10) speed regimes in four wind tunnel facilities at the NASA Langley Research Center. An overset grid, Navier-Stokes flow solver has been enhanced and demonstrated on a matrix of proximity cases and on a dynamic Separation simulation of the bimese configuration. Steady-state predictions with this solver were in excellent agreement with wind tunnel data at Mach 3 as were predictions via a Cartesian-grid Euler solver. Experimental and computational data have been used to evaluate multi-body enhancements to the widely-used Aerodynamic Preliminary Analysis System, an engineering methodology, and to develop a new software package, SepSim, for the simulation and visualization of vehicle motions in a Stage Separation scenario. Web-based software will be used for archiving information generated from this research program into a database accessible to the user community. Thus, a framework has been established to study Stage Separation problems using coordinated experimental, computational, and engineering tools.
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simulation and analyses of Stage Separation of two Stage reusable launch vehicles
2013Co-Authors: Bandu N Pamadi, Paul V Tartabini, Kelly J. Murphy, Nathaniel Hotchko, Thomas A Neirynck, William Scallion, Peter F CovellAbstract:*† ‡ § ** †† ‡‡ NASA has initiated the development of methodologies, techniques and tools needed for analysis and simulation of Stage Separation of next generation reusable launch vehicles. As a part of this activity, ConSep simulation tool is being developed which is a MATLAB‐based front-and-back-end to the commercially available ADAMS ® solver, an industry standard package for solving multi-body dynamic problems. This paper discusses the application of ConSep to the simulation and analysis of staging maneuvers of two-Stage-to-orbit (TSTO) Bimese reusable launch vehicles, one staging at Mach 3 and the other at Mach 6. The proximity and isolated aerodynamic database were assembled using the data from wind tunnel tests conducted at NASA Langley Research Center. The effects of parametric variations in mass, inertia, flight path angle, altitude from their nominal values at staging were evaluated. Monte Carlo runs were performed for Mach 3 staging to evaluate the sensitivity to uncertainties in aerodynamic coefficients.
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End-To-End Simulation of Launch Vehicle Trajectories Including Stage Separation Dynamics
AIAA Atmospheric Flight Mechanics Conference, 2012Co-Authors: Cindy W. Albertson, Paul V Tartabini, Bandu N PamadiAbstract:The development of methodologies, techniques, and tools for analysis and simulation of Stage Separation dynamics is critically needed for successful design and operation of multiStage reusable launch vehicles. As a part of this activity, the Constraint Force Equation (CFE) methodology was developed and implemented in the Program to Optimize Simulated Trajectories II (POST2). The objective of this paper is to demonstrate the capability of POST2/CFE to simulate a complete end-to-end mission. The vehicle configuration selected was the Two-Stage-To-Orbit (TSTO) Langley Glide Back Booster (LGBB) bimese configuration, an in-house concept consisting of a reusable booster and an orbiter having identical outer mold lines. The proximity and isolated aerodynamic databases used for the simulation were assembled using wind-tunnel test data for this vehicle. POST2/CFE simulation results are presented for the entire mission, from lift-off, through Stage Separation, orbiter ascent to orbit, and booster glide back to the launch site. Additionally, POST2/CFE Stage Separation simulation results are compared with results from industry standard commercial software used for solving dynamics problems involving multiple bodies connected by joints.
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aerodynamic analyses and database development for ares i vehicle first Stage Separation
Journal of Spacecraft and Rockets, 2012Co-Authors: Bandu N Pamadi, Jeremy T Pinier, Scott D Holland, Peter F Covell, Goetz KlopferAbstract:This paper presents the aerodynamic analysis and database development for the first Stage Separation of the Ares I A106 Crew Launch Vehicle configuration. Separate databases were created for the first Stage and upper Stage. Each database consists of three components: isolated or free-stream coefficients, power-off proximity increments, and power-on proximity increments. The power-on database consists of three parts, all plumes firing at nominal conditions, the one booster deceleration motor out condition, and the one ullage settling motor out condition. The isolated and power-off incremental databases were developed using wind tunnel test data. The power-on proximity increments were developed using CFD solutions.
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modeling multibody Stage Separation dynamics using constraint force equation methodology
Journal of Spacecraft and Rockets, 2011Co-Authors: Paul V Tartabini, Matthew D. Toniolo, Carlos M. Roithmayr, Christopher D. Karlgaard, Bandu N PamadiAbstract:This paper discusses the application of the constraint force equation methodology and its implementation for multibody Separation problems using three specially designed test cases. The first test case involves two rigid bodies connected by a fixed joint, the second case involves two rigid bodies connected with a universal joint, and the third test case is that of Mach 7 Separation of the X-43A vehicle. For the first two cases, the solutions obtained using the constraint force equation method compare well with those obtained using industry- standard benchmark codes. For the X-43A case, the constraint force equation solutions show reasonable agreement with the flight-test data. Use of the constraint force equation method facilitates the analysis of Stage Separation in end-to-end simulations of launch vehicle trajectories
Guangjin Chen - One of the best experts on this subject based on the ideXlab platform.
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experimental and simulation of single equilibrium Stage Separation of methane hydrogen mixtures via forming hydrate
Fluid Phase Equilibria, 2007Co-Authors: Guangjin Chen, Shixi ZhangAbstract:Abstract To separate gas mixture through forming hydrate is a new technology, which might be applicable in recovering economically valuable gas components, such as hydrogen and ethylene from refinery gases. A set of equipment was designed and constructed for the experimental study of gas mixtures Separation efficiency via forming hydrate. Batch operation method with/without gas–liquid circulating can be adopted. The Separation efficiency for hydrogen + methane gas mixtures in pure water, 1, and 6 mol% tetrahydrofuran (THF) in initial aqueous solution were examined at different temperature, pressure, and feed gas composition conditions. The results showed that high operation pressure is needed for Separation from pure water, which is only used to the initial hydrogen enriched. With the existence of THF in aqueous solution, hydrogen was remarkably enriched in vapor phase by a single equilibrium Stage, especially when 6 mol% THF added. Based on the extended Chen-Guo hydrate model, an algorithm for vapor-hydrate flash calculation was developed to simulate the single equilibrium Stage Separation of gas mixtures. Good predict precision can be obtained by the simulating algorithm, which was then extended to simulate the experimental conditions that cannot be achieved by the limit of device.
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Experimental and simulation of single equilibrium Stage Separation of (methane + hydrogen) mixtures via forming hydrate
Fluid Phase Equilibria, 2007Co-Authors: Chang-feng Ma, Guangjin Chen, Shixi ZhangAbstract:Abstract To separate gas mixture through forming hydrate is a new technology, which might be applicable in recovering economically valuable gas components, such as hydrogen and ethylene from refinery gases. A set of equipment was designed and constructed for the experimental study of gas mixtures Separation efficiency via forming hydrate. Batch operation method with/without gas–liquid circulating can be adopted. The Separation efficiency for hydrogen + methane gas mixtures in pure water, 1, and 6 mol% tetrahydrofuran (THF) in initial aqueous solution were examined at different temperature, pressure, and feed gas composition conditions. The results showed that high operation pressure is needed for Separation from pure water, which is only used to the initial hydrogen enriched. With the existence of THF in aqueous solution, hydrogen was remarkably enriched in vapor phase by a single equilibrium Stage, especially when 6 mol% THF added. Based on the extended Chen-Guo hydrate model, an algorithm for vapor-hydrate flash calculation was developed to simulate the single equilibrium Stage Separation of gas mixtures. Good predict precision can be obtained by the simulating algorithm, which was then extended to simulate the experimental conditions that cannot be achieved by the limit of device.
Paul V Tartabini - One of the best experts on this subject based on the ideXlab platform.
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simulation and analyses of Stage Separation of two Stage reusable launch vehicles
2013Co-Authors: Bandu N Pamadi, Paul V Tartabini, Kelly J. Murphy, Nathaniel Hotchko, Thomas A Neirynck, William Scallion, Peter F CovellAbstract:*† ‡ § ** †† ‡‡ NASA has initiated the development of methodologies, techniques and tools needed for analysis and simulation of Stage Separation of next generation reusable launch vehicles. As a part of this activity, ConSep simulation tool is being developed which is a MATLAB‐based front-and-back-end to the commercially available ADAMS ® solver, an industry standard package for solving multi-body dynamic problems. This paper discusses the application of ConSep to the simulation and analysis of staging maneuvers of two-Stage-to-orbit (TSTO) Bimese reusable launch vehicles, one staging at Mach 3 and the other at Mach 6. The proximity and isolated aerodynamic database were assembled using the data from wind tunnel tests conducted at NASA Langley Research Center. The effects of parametric variations in mass, inertia, flight path angle, altitude from their nominal values at staging were evaluated. Monte Carlo runs were performed for Mach 3 staging to evaluate the sensitivity to uncertainties in aerodynamic coefficients.
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End-To-End Simulation of Launch Vehicle Trajectories Including Stage Separation Dynamics
AIAA Atmospheric Flight Mechanics Conference, 2012Co-Authors: Cindy W. Albertson, Paul V Tartabini, Bandu N PamadiAbstract:The development of methodologies, techniques, and tools for analysis and simulation of Stage Separation dynamics is critically needed for successful design and operation of multiStage reusable launch vehicles. As a part of this activity, the Constraint Force Equation (CFE) methodology was developed and implemented in the Program to Optimize Simulated Trajectories II (POST2). The objective of this paper is to demonstrate the capability of POST2/CFE to simulate a complete end-to-end mission. The vehicle configuration selected was the Two-Stage-To-Orbit (TSTO) Langley Glide Back Booster (LGBB) bimese configuration, an in-house concept consisting of a reusable booster and an orbiter having identical outer mold lines. The proximity and isolated aerodynamic databases used for the simulation were assembled using wind-tunnel test data for this vehicle. POST2/CFE simulation results are presented for the entire mission, from lift-off, through Stage Separation, orbiter ascent to orbit, and booster glide back to the launch site. Additionally, POST2/CFE Stage Separation simulation results are compared with results from industry standard commercial software used for solving dynamics problems involving multiple bodies connected by joints.
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modeling multibody Stage Separation dynamics using constraint force equation methodology
Journal of Spacecraft and Rockets, 2011Co-Authors: Paul V Tartabini, Matthew D. Toniolo, Carlos M. Roithmayr, Christopher D. Karlgaard, Bandu N PamadiAbstract:This paper discusses the application of the constraint force equation methodology and its implementation for multibody Separation problems using three specially designed test cases. The first test case involves two rigid bodies connected by a fixed joint, the second case involves two rigid bodies connected with a universal joint, and the third test case is that of Mach 7 Separation of the X-43A vehicle. For the first two cases, the solutions obtained using the constraint force equation method compare well with those obtained using industry- standard benchmark codes. For the X-43A case, the constraint force equation solutions show reasonable agreement with the flight-test data. Use of the constraint force equation method facilitates the analysis of Stage Separation in end-to-end simulations of launch vehicle trajectories
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Application of CFE/POST2 for Simulation of Launch Vehicle Stage Separation
AIAA Atmospheric Flight Mechanics Conference, 2009Co-Authors: Bandu N Pamadi, Paul V Tartabini, Matthew D. Toniolo, Carlos M. Roithmayr, Christopher D. Karlgaard, Jamshid A. SamarehAbstract:The constraint force equation (CFE) methodology provides a framework for modeling constraint forces and moments acting at joints that connect multiple vehicles. With implementation in Program to Optimize Simulated Trajectories II (POST 2), the CFE provides a capability to simulate end-to-end trajectories of launch vehicles, including Stage Separation. In this paper, the CFE/POST2 methodology is applied to the Shuttle-SRB Separation problem as a test and validation case. The CFE/POST2 results are compared with STS-1 flight test data.
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Verification of a Constraint Force Equation Methodology for Modeling Multi-Body Stage Separation
AIAA Modeling and Simulation Technologies Conference and Exhibit, 2008Co-Authors: Paul V Tartabini, Matthew D. Toniolo, Carlos M. Roithmayr, Christopher D. Karlgaard, Bandu N PamadiAbstract:This paper discusses the verification of the Constraint Force Equation (CFE) methodology and its implementation in the Program to Optimize Simulated Trajectories II (POST2) for multibody Separation problems using three specially designed test cases. The first test case involves two rigid bodies connected by a fixed joint; the second case involves two rigid bodies connected with a universal joint; and the third test case is that of Mach 7 Separation of the Hyper-X vehicle. For the first two cases, the POST2/CFE solutions compared well with those obtained using industry standard benchmark codes, namely AUTOLEV and ADAMS. For the Hyper-X case, the POST2/CFE solutions were in reasonable agreement with the flight test data. The CFE implementation in POST2 facilitates the analysis and simulation of Stage Separation as an integral part of POST2 for seamless end-to-end simulations of launch vehicle trajectories.
Kurt Chudej - One of the best experts on this subject based on the ideXlab platform.
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Combined optimization of trajectory and Stage Separation of a hypersonic two-Stage space vehicle
1995Co-Authors: Roland Bulirsch, Kurt ChudejAbstract:The calculation of optimal ascent trajectories for hypersonic space vehicles is a challenge due to the high performance requirements and the complicated vehicle characteristics. Usually one solves a large amount of ascent optimization problems with a fixed mass design and fixed Stage Separation conditions which are adjusted in a manually controlled outer iteration loop. Therefore it is desirable to include into this hard optimization process simultaneously a variation of the Stage Separation and, if available, functional relationships between the mass of important components of both Stages. The feasibility and advantages of this approach are demonstrated for the ascent of a realistically modelled two-Stage hypersonic space vehicle which is launched horizontally from Kourou
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System Modelling and Optimization - Optimization of the Stage Separation and the flight path of a future launch vehicle
System Modelling and Optimization, 1994Co-Authors: Kurt ChudejAbstract:The computed solutions for a realistic model of a hypersonic space vehicle demonstrate the feasibility of simultaneously optimizing the Stage Separation and the flight path by an indirect method. This is enabled by using state of the art optimization codes such as multiple shooting and a generalization of the necessary conditions of optimal control theory. The later is necessary in order to include in the problem formulation simultaneously such important features as piecewise defined model functions and state constraints.