Chamber pressure

About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.

Characterization of Fuel Regression in a Radial Flow Hybrid Rocket

Abstract: Reliable ignition and stable combustion have been achieved in a lab-scale radial-e ow hybrid rocket engine. The device utilizes 85% hydrogen peroxide and polyethylene and was tested at chamber pressures ranging from 118 to 238 psia. Fuel regression behavior was characterized with respect to initial geometry and mass e ux. The measured regression rates are greater than observed in axial port designs at the same e ux and chamber pressure levels. Although the regression behavior is effected locally by the three-dimensional e ow structure, the results were more uniform than predicted by lumped parameter ballistics approximations. For this reason, radial-e ow designs with acceptable fuel utilization appear to be feasible.

Evaluation of trifluoroacetic anhydride as an alternative plasma enhanced chemical vapor deposition chamber clean chemistry

Abstract: One environmental issue currently facing the semiconductor industry is the emission of perfluorinated compounds (PFCs) from a variety of processes including chamber cleaning following plasma enhanced chemical vapor deposition (PECVD) of dielectrics. The emission of PFCs has been targeted for reduction due to the contribution of these species to global warming. An option under investigation is the use of alternative compounds that emit lower amounts of global warming species. The current study presents chamber cleaning times and emissions from the use of one such species, trifluoroacetic anhydride (TFAA), in a widely used commercial PECVD tool, the Novellus Concept One 200. A central composite design-of-experiments was employed to calculate response surfaces for the chamber clean time and PFC emission concentrations as the chamber pressure, TFAA flow rate, and oxygen flow rate were varied. The chamber clean times were measured using optical emission spectroscopy, quadrupole mass spectrometry, as well as Fo...

Design of an artificial lung compliance chamber for pulmonary replacement.

Abstract: Matching the impedance of an artificial lung for pulmonary replacement to native pulmonary impedance is important in preventing right ventricular dysfunction. A lumped-parameter theoretical model and bench-top experiments were used to investigate the effect of a prototype compliance chamber on input impedance. The bench-top simulation consisted of a pulsatile flow generator, a prototype compliance chamber, and a low resistance artificial lung connected in series. Effective compliance was varied using pneumatic compression. The theoretical model considered a similar circuit with resistors before and after a compliance element. The bundle flow pulsatility (flow amplitude divided by average flow) and input impedance were calculated in the theoretical and experimental models. More compliance and lower upstream resistance result in lower bundle flow pulsatility and reduced first harmonic impedance. Matching the time scale of the circuit to the period of pulsatile flow also reduces impedance. The bench-top circuit demonstrated an optimal chamber pressure at which first harmonic impedance is reduced by 80%. The prototype compliance chamber in series with the artificial lung more closely matches native pulmonary impedance. The lumped-parameter model and the bench-top simulation will aid in the design and testing of compliance chamber modifications to improve its efficiency.