International Telemetering Conference Proceedings / October 26-29, 1998 / Town & Country Resort Hotel and Convention Center, San Diego, California / In support of the X-33 single-stage-to-orbit program, NASA Dryden Flight Research Center was selected to provide continuous range communications of the X-33 vehicle from launch at Edwards Air Force Base, California, through landing at Malmstrom Air Force Base, Montana, or at Michael Army Air Field, Utah. An extensive real-time range simulation capability is being developed to ensure successful communications with the autonomous X-33 vehicle. This paper provides an overview of the various levels of simulation, integration, and test being developed to support the X-33 extended range subsystems. These subsystems include the flight termination system, L-band command uplink subsystem, and S-band telemetry downlink subsystem.

The purpose of this thesis is to design a robust test facility for a small space nuclear power system and model its physical behavior under different scenarios. The test facility will be used to simulate a 1-10kWe nuclear reactor, its electrical generation, and heat removal capabilities. This simulator will be used to explore, test and understand the steady-state and transient operation capabilities of small space nuclear power systems. Currently, the system is planned to operate on a variable, electrical heat source directly connected to heat pipes. The heat pipes are to be stainless steel with a water working fluid. These heat pipes will then be connected to a power conversion simulator or actual power conversion technologies. The power conversion simulator is connected to a radiator using a water based heat pipe network using fins and connecting plates in a cylindrical geometry. Modeling of the facility was performed using two different analysis programs, STELLA and SolidWorks. STELLA was used as a lumped sum heat transport code, and SolidWorks was used as a more accurate system to verify the validity of STELLA's results. Both programs were used to analyze startup, heat pipe failures, and loss of power conversion with the end goal of finding safe operational transient scenarios for the transient test facility. / Graduation date: 2013

Inlet headers in the primary heat transport system(PHTS) of CANDU type reactors, are used to collect the coolant coming from the steam generators and distribute them into the reactor core via several feeders. During a postulated loss of coolant accident (LOCA), depressurization and vapor supplement into the core may occur, which results a deterioration in the heat transfer from fuel to the coolant. When a depressurization occurs, &ldquo / Emergency Coolant Injection(ECI)&rdquo / system in the PHTS in CANDU reactors, is automatically become active and supply coolant is fed into the reactor core via the inlet header and feeders. . This study is focused on the experimental and computational investigation of the ECI effect during a LOCA in a CANDU inlet header. The experiments were carried out in METU Two-Phase Flow Test Facility which consists of a scaled CANDU inlet header having 5 connected feeders. The same tests were simulated with a one dimensional two-fluid computer code, CATHENA, developed by Atomic Energy of Canada Limited(AECL). The average void fraction and the two phase mass flowrate data measured in the experiments are compared with the results obtained from CATHENA simulation. Although a few mismatched points exist, the results coming from two different studies are mostly matching reasonably. Lack of three-dimensional modeling for headers in CATHENA and experimental errors are thought to be the reasons for these dismatches.

International Telemetering Conference Proceedings / October 25-28, 1999 / Riviera Hotel and Convention Center, Las Vegas, Nevada / This paper provides a current review of a new installed system test facility (ISTF) capability for the Air Force and Navy. The requirements, design characteristics, and status of the joint-service Communications, Navigation, Identification Simulator (CNIS) developments will be covered along with their relationships with the Air Force’s Avionics Test and Integration Complex (ATIC) and the Navy’s Air Combat Environment Test and Evaluation Facility (ACETEF) ISTFs. These developments provide the services an interactive spatially, temporally, and tactically coherent signal environment for development and operational test and evaluation. The Joint Communications Simulator (JCS) and Joint Data Link Simulator (JDLS) capabilities, integration aspects, and development schedules (2000 IOC) will also be addressed. Finally, installed system test and evaluation concepts, both Air Force and Navy, using the simulators will be previewed to assist upcoming development programs in identifying potential applications.

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The objectives of this doctoral thesis are to give a basisincluding methods for the development of stationary polymerelectrolyte fuel cell (PEFC) systems for combined heat andpower production. Moreover, the objectives include identifyingprerequisites, requirements and possibilities for PEFC systemsproducing heat and power for buildings in Sweden. The PEFCsystem is still in a pre-commercial state, but low emissionlevels, fast dynamics and high efficiencies are promisingcharacteristics. A thermodynamic model to simulate stationary PEFC systemshas been constructed and pinch technology and exergy analysesare utilised to design and evaluate the system. The finalsystem configuration implies a high total efficiency ofapproximately 98 % (LHV). A flexible test facility was built in connection with theresearch project to experimentally evaluate small-scalestationary PEFC systems at KTH. The research PEFC system hasextensive measurement equipment, a rigorous control system andallows fuel cell systems from approximately 0.2 to 4 kWel insize to be tested. The simulation models of the fuel processorand the fuel cell stack are verified with experimental datataken from the test facility. The initial evaluation andsimulation of the first residential installation of a PEFCsystem in Sweden is also reported. This PEFC system, fuelled bybiogas and hydrogen, is installed in an energy system alsoincluding a photovoltaic array, an electrolyser and hydrogenstorage. Technical aspects of designing a fuel cell system-basedenergy system, including storages and grid connections, whichprovides heat and power to a building are presented in thisthesis. As a basis for the technical and economic evaluations,exemplifying energy systems are constructed and simulated. Fuelcell system installations are predicted to be economicallyunviable for probable near-term conditions in Sweden. The mainfactor in the economic evaluations is the fuel price. However,fuel cell system installations are shown to have a higher fuelutilisation than the conventional method of energy supply. The methods presented in this thesis serve as a collectedbasis for continued research and development in the area. Keywords:Small-scale, stationary, fuel cell system,polymer electrolyte fuel cell, PEFC system, reformer,thermodynamic modelling, pinch technology, exergy analyses,system configuration, test facility, experiments, application,simulation, installation, energy system, energy storage, heatand power demand.

The test facility ROCOM (Rossendorf Coolant Mixing Model) has been built for the investigation of coolant mixing processes in the reactor pressure vessel of pressurised water reactors (PWR). ROCOM is a 1:5 model of the German PWR KONVOI and has been designed for a wide range of different mixing scenarios. ROCOM disposes of four loops with fully controllable coolant pumps. The test facility is operated with demineralised water. For the investigation of mixing, tracer solution (water labelled with salt) is injected into the facility. The transient distribution of the electrical conductivity is is measured at different positions of the flow path by means of wire-mesh sensor technique with high resolution in space and time. The measured conductivity is transformed into a dimensionless mixing scalar. The mixing at quasi-stationary conditions (constant loop mass flow rates) has been investigated in the presented experiments. That concerned nominal operation conditions, the operation with a reduced number of loops and the investigation of cold-water transients with running pumps and conditions of developed natural circulation. In special experimental series, the reproducibility of the results at identicla boundary conditions within the confidence intervalls has been shown. Further, the influence of various factors on the mixing has been investigated. This included the pressure losses at the core bottom plate, the global coolant flow level and the influence of the loop flow rate on the perturbed sector at the core inlet. An analysis of the measurement error of the used measurement technique completes the report.

<p>The objectives of this doctoral thesis are to give a basisincluding methods for the development of stationary polymerelectrolyte fuel cell (PEFC) systems for combined heat andpower production. Moreover, the objectives include identifyingprerequisites, requirements and possibilities for PEFC systemsproducing heat and power for buildings in Sweden. The PEFCsystem is still in a pre-commercial state, but low emissionlevels, fast dynamics and high efficiencies are promisingcharacteristics.</p><p>A thermodynamic model to simulate stationary PEFC systemshas been constructed and pinch technology and exergy analysesare utilised to design and evaluate the system. The finalsystem configuration implies a high total efficiency ofapproximately 98 % (LHV).</p><p>A flexible test facility was built in connection with theresearch project to experimentally evaluate small-scalestationary PEFC systems at KTH. The research PEFC system hasextensive measurement equipment, a rigorous control system andallows fuel cell systems from approximately 0.2 to 4 kWel insize to be tested. The simulation models of the fuel processorand the fuel cell stack are verified with experimental datataken from the test facility. The initial evaluation andsimulation of the first residential installation of a PEFCsystem in Sweden is also reported. This PEFC system, fuelled bybiogas and hydrogen, is installed in an energy system alsoincluding a photovoltaic array, an electrolyser and hydrogenstorage.</p><p>Technical aspects of designing a fuel cell system-basedenergy system, including storages and grid connections, whichprovides heat and power to a building are presented in thisthesis. As a basis for the technical and economic evaluations,exemplifying energy systems are constructed and simulated. Fuelcell system installations are predicted to be economicallyunviable for probable near-term conditions in Sweden. The mainfactor in the economic evaluations is the fuel price. However,fuel cell system installations are shown to have a higher fuelutilisation than the conventional method of energy supply.</p><p>The methods presented in this thesis serve as a collectedbasis for continued research and development in the area.</p><p><b>Keywords:</b>Small-scale, stationary, fuel cell system,polymer electrolyte fuel cell, PEFC system, reformer,thermodynamic modelling, pinch technology, exergy analyses,system configuration, test facility, experiments, application,simulation, installation, energy system, energy storage, heatand power demand.</p>

A Computational Fluid Dynamics/Computational Fluid Dynamics (CFD/CSD) coupling interface was developed to obtain aeroelastic solutions of a morphing rotor. The methodology was implemented in Fully Unstructured Navier-Stokes (FUN3D) solver, which communicates aerodynamic forces on the blade surface to University of Michigan’s Nonlinear Active Beam Solver (UM/NLABS) and then imports structural deflections of the blade surface during each time step. Development of this methodology adds the capability to model elastic rotors with flexible airfoils. The method was validated through an aerodynamic work analysis, comparison of sectional blade loads and deflections with experimental data, and two-dimensional stability analyses for pitch/plunge flutter and camber flutter. Computational simulations were performed for a rotor in forward flight with the CFD/CSD solver and with a comprehensive CSD solver using finite-state (F-S) aerodynamics, and results were compared. Prescribed three-per-revolution camber deflections were then applied, and solutions of the CFD/CSD and comprehensive CSD computations indicated that three-per-revolution camber actuation has the potential to minimize hub forces and moments with deflections as small as 0.25%c. In anticipation of active rotor experiments inside enclosed facilities, the capability of CFD for accurately simulating flow inside enclosed volumes was examined. It was determined that URANS models are not suitable for rotor simulations in an enclosed facility, and components that are a distance of two to three rotor radii from the hub were also observed to have a large influence on recirculation and performance.

In CANDU reactors, under normal operating conditions, the inlet headers collect and distribute single-phase liquid flow (heavy water) to the fuel cooling channels via the feeders. However, under some postulated loss of coolant accidents, the inlet headers may receive two-phase fluid (steam/water) and the fluid forms a stratified region inside the header. To predict the thermalhydraulic behaviour of headers for the reactor safety analysis, the two-phase flow distribution within the headers and through the feeders must be modelled. In order to analyse the two-phase flow behaviour of a scaled CANDU inlet header / a transparent and instrumented version of a header with 5 feeders was previously built in the Mechanical Engineering Department of Middle East Technical University (METU-Two Phase Flow Test Facility / METU-TPFTF). The aim of this study is to investigate two-phase flow distribution through multiple outlets from such a horizontal drum both numerically and experimentally. For this purpose, three-dimensional incompressible finite difference equations in cylindrical coordinates were derived by using two-fluid model to simulate adiabatic two-phase flow (air/water) in the header numerically. The discretized equations were then programmed into a computer code which was developed specifically for modelling the header type geometry. A method based on the principles of Implicit Multi Field (IMF) technique has been utilised to solve those equations. The solution algorithm was tested by using some numerical benchmark problems. A number of experimental tests covering single and two-phase flow distribution through outlet pairs from the header were performed. Void fractions and flow rates obtained from these tests are in good agreement with the code results. The code also predicts the void fraction and pressure distribution in the header satisfactorily.