Topic
Chamber pressure
About: Chamber pressure is a research topic. Over the lifetime, 2988 publications have been published within this topic receiving 30725 citations.
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Papers
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08 May 1972
TL;DR: In this paper, a flexible walled chamber is used under a rigid pallet for transporting a load over irregular surfaces, where flapper valves are constructed and arranged to rapidly respond to the pressure differential across the holes.
Abstract: Air pressure is conserved in an air cushion load conveying apparatus by valve elements disposed within the air pressure chamber in operative association with an array of relatively small holes which provide the pressurized air cushion between the wall of the chamber and an adjacent surface. The valve elements are constructed and arranged to rapidly respond to the pressure differential across the holes. They quickly open and transmit chamber pressure to the pressurized air cushion when an object is disposed close to the hole and rapidly close and preserve pressure when there is no object and concomitant air cushion disposed adjacent the hole. The valve elements are flapper valves made of a single large perforated flexible sheet or a number of smaller sheets which substantially obstruct the holes in the presence of a high differential pressure. The flapper valves inherently leak, which makes them sensitively respond to changes in pressure. The leakage is, however, not enough to cause an undue loss of air through closed holes. Bleed holes may be provided, if necessary, to accelerate movement under special conditions. The perforated chamber wall may be rigid for operating against regular smooth surfaces or it may be flexible for operating against irregular or interrupted surfaces. A flexible walled chamber may be used under a rigid pallet for transporting a load over irregular surfaces. The upper surface of the rigid pallet may also be perforated and valved to facilitate sliding loads on and off, and the pressurized air may be alternately supplied to the upper and lower portions to facilitate loading, unloading and transport.
10 citations
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BMW1
TL;DR: In this article, a closed circuit with two or more heat-exchangers and a compressor is shown, where the compressor is regulated by the pressure in its driving chamber and a tapping leads from the circuit to the chamber and from there back to it at the compressor suction side, and contains flow-limiting and regulating valves for the chamber pressure.
Abstract: Carbon dioxide in a closed circuit (2) is circulated by a compressor (1) and via two or more heat-exchangers (3,5) in-series. On one side of the circuit the compressor is situated between the exchangers, while on the other there is an expansion valve (4) between them. The compressor is regulated by the pressure in its driving chamber (18). A tapping (22) leads from the circuit to the chamber and from there back to it at the compressor suction side, and contains flow-limiting (21) and regulating valves (23) for the chamber pressure. Seen in the flow direction in the circuit (2), the tapping is situated between the first exchanger (5) and the expansion valve (4), so that it cools the compressor.
10 citations
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TL;DR: In this paper, a microelectromechanical system thruster with a design thrust of 100mN was fabricated and tested and three catalyst loading conditions were tested and experimentally optimized.
Abstract: Amicroelectromechanical systemsmonopropellant thruster having a design thrust of 100mNwas fabricated and tested. Hydrogen peroxide (90 wt%), which is a green propellant, was selected as the monopropellant. Platinumwas used to decompose the hydrogen peroxide, and it was coated on Al2O3 via impregnation. Three catalyst loading conditions were tested and experimentally optimized. The optimized catalyst was directly inserted into the thruster chamber to enhance decomposition performance because its surface-to-mass ratio significantly affected its performance. The microelectromechanical systems thruster was composed of eight photosensitive cylindrical-type glasses. An additional reduction process was carried out after the thermal bonding procedure because performance degradation of the catalyst was detected at this stage. The microelectromechanical systems thruster decomposed hydrogen peroxide well. However, chamber instability was observed. This instability resulted from an insufficient pressure drop at the injector. Therefore, it is necessary to increase the feeding pressure and reinforce the injector wafer to decrease chamber instability.
10 citations
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01 Jan 2000TL;DR: In this article, a mathematical model for the kinematics, piston chamber pressure and output flow rate of axial piston pumps with conical cylinder blocks is developed to study the effect of the port silencing grooves on these variables.
Abstract: In this paper a mathematical model is developed for the kinematics, piston chamber pressure and output flow rate of swash plate axial piston pumps with conical cylinder blocks. Software is developed to study the effect of the port silencing grooves on these variables. The study led to a proposed geometry of the suction and delivery silencing grooves that causes gradual rise and drop of the piston chamber pressure, with cavitation avoided, for a pump with certain dimensions. The recommended groove dimensions render less fluctuation in the output flow rate for a nine-piston pump. The developed model can be used to conduct a similar study for any swash plate axial piston pump.
10 citations
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TL;DR: In this paper, a new device is designed to gain access to an additional physical quantity, which is needed to assess the aerodynamic non-equilibrium state of the jet, and the resulting set of experimental data is used with a numerical procedure based on gas dynamics theory, yielding free-stream supersonic plasma jet values from the measurements behind the induced shock wave.
Abstract: Low pressure plasma spraying (LPPS) is a thermal spraying technique that has found a niche for low oxidation products. It uses a low pressure environment (i.e., chamber pressure between 2 and 90 kPa) and yields supersonic plasma jets. The enthalpy probe technique is a common measurement method in plasmas. However LPPS jets are difficult to diagnose as their supersonic nature forces the apparition of a shock wave in front of any measuring device inserted in the jet. Incomplete or erroneous assumptions are usually invoked to overcome the difficulties associated with this shock wave and carry out the LPPS jet diagnosis from enthalpy probe measurements. In this work, a new device is designed to gain access to an additional physical quantity, which is needed to assess the aerodynamic non-equilibrium state of the jet. It is combined with enthalpy probe measurements, and the resulting set of experimental data is used with a numerical procedure based on gas dynamics theory, yielding free-stream supersonic plasma jet values from the measurements behind the induced shock wave. The results agree well with the phenomenology of supersonic jets in aerodynamic nonequilibrium. However this new method is restricted by the local thermodynamic equilibrium assumption, which is directly linked with the pressure and temperature conditions of the plasma jet.
10 citations