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To conduct system level studies on internal combustionengines reduced order models are required in order tokeep the computational load below reasonable limits.By its nature a reduced order model is ...

This paper presents a concept for new piston expander utilizing nozzle as part of a secondary steam cycle to recover exhaust energy. A commercial 1D simulation tool, AVL BOOST, was used to model the system, and comparison study was carried out between the conventional and nozzle piston expanders. It was found the nozzle piston expander could increase output power from a minimum of 0.73kW up to a maximum of 4.75kW. The simulation study has shown that the concept of using nozzle to admit steam into the piston expander has potential to improve engine system level efficiency.

An LHP-based thermal control system for cryocoolers on the Alpha Magnetic Spectrometer (AMS-02) has been designed, and analyzed by means of the system level model based on Sinda/Fluint. Integrated with the International Space Station (ISS) model by means of a time-varying sink temperature definition, the performance of LHP-based thermal control is investigated. A parametric analysis is carried out also to understand the influence of critical parameters on the operation of LHP.

This paper will discuss the vehicle chassis top down design approach that includes the nonlinearity and sub-system interactions such as tire and road, (left and right) interaction between two or more parts connected by bushings, springs, bolts, stabilizer-bar, etc... The proposed method called "sub-system analysis method" would allow for the inclusion of realistic boundary conditions and proper load simulation, and it would provide the ability to visualize and evaluate dynamic structural phenomena and complex component interaction. This approach would also facilitate the evaluation of design changes that may affect load propagation and/or load magnitude. All of the advantages of the sub-system analysis method mentioned above would allow for a greater understanding of the chassis sub-system as a whole and help correctly identify the design requirements needed for the individual components that make up such chassis sub-systems. This approach is of a holistic one and it is unified in a sense that it lends itself to system identification and optimization as a whole.

Regenerative life support systems for long duration human space exploration missions present unique design challenges that are also reflected in constructing behavior models of these systems for analysis purposes. These systems have multiple modes of operation and complex non-linear dynamics that occur at multiple time scales. Coarse grained analysis of the complete system over long duration and fine grained analysis of smaller system elements while avoiding computational intractability can be achieved by using multiple modeling and simulation paradigms. We describe a multi-level simulation model of an advanced life support system. The simulation model couples a discrete-event approach at the system level, with more detailed hybrid (continuous/discrete) physical system modeling at the sub-system level.

The I-Suit has been tested in varying environments at Johnson Space Center (JSC). This includes laboratory mobility testing, KC-135 partial gravity flights, and remote field testing in the Mojave Desert. The experience gained from this testing has provided insight for design improvements. These improvements have been an evolutionary process since 1998 to the present. The design improvements affect existing suit components and introduce new components for systems processing and human/robotic interface. Examples of these design improvements include improved mobility joints, a new helmet with integrated communications and displays capability, and integration of textile switches for control of suit functions and tele-robotic operations. This paper addresses an overview of I-Suit design improvements and results of manned and unmanned performance tests. The performance tests include mobility joint testing, helmet visibility testing, and system level manned testing of the improved suit components.

The simulation of a power system such as the More Electric Aircraft is a complex problem. There are conflicting requirements of the simulation, for example in order to reduce simulation run-times, power ratings that need to be established over long periods of the flight can be calculated using a fairly coarse model, whereas power quality is established over relatively short periods with a detailed model. An important issue is to establish the requirements of the simulation work at an early stage. This paper describes the modelling and simulation strategy adopted for the UK TIMES project, which is looking into the optimisation of the More Electric Aircraft from a system level. Essentially four main requirements of the simulation work have been identified, resulting in four different types of simulation. Each of the simulations is described along with preliminary models and results.