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Full-Text Articles in Engineering
Experimental And Computational Studies Of Temperature Gradient Driven Molecular Transport In Gas Flows Through Nano/Micro-Scale Channels, Yen-Lin Han, Alina A. Alexeenko, Marcus Young, Eric Phillip Muntz
Experimental And Computational Studies Of Temperature Gradient Driven Molecular Transport In Gas Flows Through Nano/Micro-Scale Channels, Yen-Lin Han, Alina A. Alexeenko, Marcus Young, Eric Phillip Muntz
School of Aeronautics and Astronautics Faculty Publications
Studies at the University of Southern California have shown that an unconventional solid-state device, the Knudsen Compressor, can be operated as a micro-scale pump or compressor. The critical components of Knudsen Compressors are gas transport membranes, which can be formed from porous materials or densely packed parallel arrays of channels. An applied temperature gradient across a transport membrane creates a thermal creep pumping action. Experimental and computational techniques that have been developed for the investigations will be discussed. Experimental studies of membranes formed from machined aerogels, activated by radiant heating, have been used to investigate thermal creep flows. In computational …
Numerical Simulations Of Supersonic Flow In A Linear Aerospike Micronozzle, A Zilic, D L. Hitt, Alina A. Alexeenko
Numerical Simulations Of Supersonic Flow In A Linear Aerospike Micronozzle, A Zilic, D L. Hitt, Alina A. Alexeenko
School of Aeronautics and Astronautics Faculty Publications
In this study, we numerically examine thrust performance of the linear aerospike nozzle micro-thruster for various nozzle spike lengths and flow parameters in order to identify optimal geometry(s) and operating conditions. Decomposed hydrogen-peroxide is used as the monopropellant in the studies. Performance is characterized for different flow rates (Reynolds numbers) and aerospike lengths, and the impact of micro-scale viscous forces is assessed. It is found that 2-D full micro-aerospike efficiencies can exceed axisymmetric micro-nozzle efficiencies by as much as 10%; however, severe penalties are found to occur for truncated spikes at low Reynolds numbers.
Performance Modeling Of An Rf Coaxial Plasma Thruster, William B. Stein, Alina A. Alexeenko, Ivana Hrbud, Evgeniy Bondar
Performance Modeling Of An Rf Coaxial Plasma Thruster, William B. Stein, Alina A. Alexeenko, Ivana Hrbud, Evgeniy Bondar
School of Aeronautics and Astronautics Faculty Publications
The RF plasma thruster has considerable potential to ease the impact of severe constraints on power, mass, volume and lifetime of microsatellite propulsion systems. This concept is classified as an electrothermal propulsion system and exploits RF capacitively coupled discharge (RFCCD) for heating of a propellant. The plasma is characterized as a low-power discharge possessing a low-current density with high uniformity and propagating through low-pressure gas. To assess computationally the thruster’s propulsive capabilities as a function of mass flow rate, electrode separation, RF frequency and power input, a numerical model comprises particle-in-cell/Monte Carlo (PIC/MCC) and Direct Simulation Monte Carlo (DSMC) algorithms. …