Chamber pressure

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

Theoretical Analysis of Wankel Engine Combustion

Abstract: A one-dimensional model for. the spark ignition Wankel engine combustion is presented, The model is based on the use of a turbulent diffusivity for heat and mass transfer by which the motion of the finite-thickness, unsteady turbulent flame is calculated. A one-step second order reaction rate equation is used and wall heat transfer losses are included. The instantaneous chamber pressure and the local and instantaneous gas temperature, density, and velocity are calculated. Results are presented for a typical engine design. Initial results of two parametric studies are also reported, but their generalization is not undertaken, at this point, due to the complexity of the process.

Apparatus and method for applying coatings onto the interior surfaces of components and related structures produced therefrom

Abstract: Provided is a methodology and system (1) for applying coatings onto the interior surfaces of components (40). The approach comprises a vapor creation device (3) (for example an electron beam or laser that evaporates a single or multiplicity of solid or liquid sources), a vacuum chamber (4) having a moderate gas pressure (between about 10-4 to about 103 Torr) and a inert gas jet (5) having controlled velocity and flow fields of gas jet. The gas jet is created by a rarefied, inert gas supersonic expansion through a nozzle (30). By controlling the carrier gas flow into a region upstream of the nozzle an upstream pressure is achieved (i.e. the gas pressure prior to its entrance into the processing chamber through the nozzle). The carrier gas flow and chamber pumping rate control the downstream (or chamber) pressure (i.e., downstream of the nozzle). The ratio of the upstream to downstream pressure along with the size and shape of the nozzle opening controls the speed of the gas entering the chamber. The carrier gas molecular weight (compared to that of the vapor) and the carrier gas speed controls its effectiveness in redirecting the vapor atoms via binary collisions towards the substrate (40). The speed and flux of the atoms entering the chamber, the nozzle parameters, and the operating chamber pressure can all vary leading to a wide range of accessible processing conditions. Vapor (15) created from a source (25) is transported into the interior regions of a component using binary collisions between the vapor and gas jet atoms (17). Under certain process conditions these collisions enable the vapor atoms to scatter onto the interior surfaces of the component and deposit.

Viscous effects in supersonic mems-fabricated micronozzles

Abstract: A contoured converging-diverging micronozzle has been created for the acceleration of gas flows to supersonic velocities. Extruded two-dimensional devices, with minimum throat widths averaging 19 microns and 35 microns, are etched using deep reactive ion etching. Mass flow efficiencies through the nozzles range from 87% to 98% and are within experimental error to those predicted by a 2-D NavierStokes fluid simulation for Reynolds numbers 350-3800. The thrust of a 16.9 to 1 expansion ratio nozzle was measured to be 11.3 mN at 97 psia chamber pressure. This corresponds to an exit velocity of 590 m/s, which is Mach 3.8 for a chamber temperature of 300 K. Thrust efficiency is found to deviate considerably from the 2-D numerical model at low Reynolds numbers due to the development of sidewall boundary layers.

Slant plate type compressor with variable displacement mechanism

Abstract: A slant plate type compressor with a capacity or displacement adjusting mechanism is disclosed. The compressor includes a housing having a cylinder block provided with a plurality of cylinders and a crank chamber. A piston is slidably fitted within each of the cylinders and is reciprocated by a drive mechanism which includes a member having a surface with an adjustable incline angle. The incline angle is controlled by the pressure in the crank chamber. The pressure in crank chamber is controlled by control mechanism which comprises a passageway communicating between the crank chamber and a suction chamber, a first valve device to control the closing and opening of the passageway and a second valve device to control pressure in an actuating chamber. The first valve device includes a bellows valve element and a valve shifting element. The valve shifting element of which one end is exposed in the actuating chamber is coupled to the bellows to apply a force to the bellows at another end and thereby shift a control point of the bellows in response changes in the actuating chamber pressure.

Augmented carbonaceous substrate alteration

Abstract: Accurately altering a precisely located site on a substrate by: (a) providing a vacuum chamber; (b) providing an energy beam; (c) providing a source of a hydrocarbon and a conduit extending between the source and the chamber, the hydrocarbon being capable of being adsorbed in the substrate and of interacting with the energy beam to alter the substrate; (d) positioning the substrate in the chamber to be exposed to hydrocarbon delivered by the conduit; (e) introducing into the conduit a carrier having a vapor pressure above the vapor pressure of the hydrocarbon, the carrier being in vapor form under conditions existing in the conduit and having a bulk velocity that transports the hydrocarbon by molecular collisions into the chamber, the hydrocarbon being adsorbed on the surface of the substrate, free carrier molecules being drawn off sufficiently rapidly to maintain low pressure in the chamber; and (e) while maintaining the low chamber pressure, directing the energy beam to the site in the presence of the absorbed hydrocarbon, in a manner to convert the hydrocarbon to a coherent carbonaceous deposit of predetermined desired form, adherent to the substrate at the site to render the site opaque. Most preferably, a focused ion beam is used to repair an opaque defect in a photolithographic mask.