Chamber pressure

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

Subscale Tool for Determining Transverse Combustion Response

Abstract: Experimental results of a transverse combustion instability rating tool using gas-center swirl-coaxial injectors are presented. A 2D rectangular chamber that produces strong transverse instability waves was used to determine the feasibility as a stability rating tool for a minimum representative set of elements. Four different configurations were tested to determine the modes driven most in the chamber. With the driving modes determined, the chamber was set up to determine its ability to be used as a tool to study other element’s responses to the transverse acoustic combustion waves. When limited driving injectors were used results show that the chamber acoustic waves are driven at the primary frequency from the outer injectors, which are located near a pressure anti-node. It was also observed that the oxidizer only portions of the chamber tended to dampen the acoustic waves. The case where only four outer injectors (two on each side) flowed propellant was the most unstable case producing peak-to-peak oscillations greater than chamber pressure, indicating that this configuration could be used to study and measure the combustion response of a centrallylocated minimum representative set of injector elements to high-amplitude velocity oscillations. From these series of tests it was determined that the chamber and injector designs can be used as a tool to drive acoustic waves and allow a study element to be placed in the chamber to determine its response to the instability.

Another Look at the Practical and Theoretical Limits of an Expander Cycle, LOX/H2 Engine

Abstract: : Advances in materials and increases in turbopump efficiencies necessitate another look at the theoretical and practical limits for growth in chamber pressure and thrust in a liquid rocket expander cycle engine The basic equations for turbopump power and heat flux rate out of the cooling jacket are examined to determine the theoretical limits for chamber pressure using an expander cycle Turbopump efficiencies and operating speed limits for a LOX/H2 expander engine are explored to determine practical limits as applied to the chamber pressure

Use of plasma impedance monitoring for the determination of SF6 reactive ion etch process end points in a SiO2/Si system

Abstract: It is shown here that plasma impedance monitoring can be used successfully to determine the end point of reactive ion etching of a SiO2 layer lying on a Si substrate in SF6 plasma. The usefulness of this technique is demonstrated using a commercial Plasma Impedance Monitoring (PIM) system. The end point conditions are tested by monitoring changes in the fundamental and the first four harmonic components of the RF current, RF voltage, phase between RF voltage and current, RF discharge power and RF impedance. The best process monitoring parameter found in this work is modeled as a polynomial equation of RF input power, chamber pressure and gas flow rate, from which the end point can be predicted with good precision and easily detected by the PIM. The end point conditions are confirmed by both Fourier Transform Infrared Spectroscopy (FTIR) measurements and via observation of plasma color changes.