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Total pressure

About: Total pressure is a research topic. Over the lifetime, 5199 publications have been published within this topic receiving 66658 citations.


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Journal ArticleDOI
TL;DR: In this article, the authors consider the case of a constant pressure photoionized cloud in pressure equilibrium with a surrounding hot gas and show that the radiation pressure of the internally generated line emission makes a significant contribution to the total pressure in standard broad-line region models, and that models with either a higher ionization parameter or lower gas density are dominated by radiation pressure.
Abstract: We discuss two constraints on the existence and stability of quasar emission-line gas. The case of a constant pressure photoionized cloud in pressure equilibrium with a surrounding hot gas is considered. We show that the radiation pressure of the internally generated line emission makes a significant contribution to the total pressure in standard broad-line region models, and that models with either a higher ionization parameter or lower gas density are dominated by radiation pressure and hence unstable. Further, clouds with ionization parameters lower than the standard value cannot be supported by any hot gas which is heated only by the observed radiation field. The result is a strict limit on the range of parameters which permit the existence of the observed emission-line gas. These results offer a natural explanation for the similarities among emission-line spectra of active galactic nuclei.

22 citations

Journal ArticleDOI
TL;DR: In this article, Nitrogen doped silicon films have been deposited by low pressure chemical vapour deposition from disilane Si 2 H 6 and ammonia NH 3, pointing out the influences of the deposition temperature, the total pressure and the gas flow rates.

22 citations

Journal ArticleDOI
TL;DR: In this paper, the influence of air addition to the products of continuous spin detonation of a hydrogen-air mixture and to the mixing region on parameters of detonation waves, pressure in the combustor, and specific impulse is studied.
Abstract: Results of an experimental study in a flow-type annular cylindrical combustor with an outer diameter of 30.6 cm are described. The influence of air addition to the products of continuous spin detonation of a hydrogen-air mixture and to the mixing region on parameters of detonation waves, pressure in the combustor, and specific impulse is studied. The range of continuous spin detonation of the hydrogen-air mixture is extended to specific flow rates of the mixture equal to 560 kg/(sec · m2) and fuel-to-air equivalence ratios equal to 0.5–4.4. It is demonstrated that addition of air decreases the detonation velocity, increases the pressure in the combustor and thrust, and decreases the specific flow rate of the fuel. The total pressure loss due to the mixing process and heat transfer to a colder gas increases. The minimum specific flow rate of hydrogen reached in the combustor of the examined geometry is 0.04 kg/(h · N).

22 citations

Journal ArticleDOI
TL;DR: In this article, a quasi-one-dimensional model for the planar, confined shear layer is constructed with the purpose of obtaining estimates of entropy production and pressure variation due to turbulent mixing.
Abstract: A quasi-one-dimensional model for the planar, confined shear layer is constructed with the purpose of obtaining estimates of entropy production and pressure variation due to turbulent mixing. The turbulent Prandtl and Lewis numbers are assumed to be unity. It is found that entropy production is strongly coupled to the intrinsic compressibility, with total pressure losses becoming significant as the convective Mach number increases

22 citations

Proceedings ArticleDOI
20 Jun 1999
TL;DR: In this paper, a fundamental experimental investigation was conducted on the flow characteristics and performance of a diffuser ingesting a thick boundary layer of a high shape factor, and the performance of the diffuser was quantified by the two parameters of primary concern in jet engine applications: total pressure recovery and total pressure distortion at the fan face (i.e., the exit) calculated from the total pressure data measured inside the duct.
Abstract: A fundamental experimental investigation was conducted on the flow characteristics and performance of a diffuser ingesting a thick boundary layer of a high shape factor. The duct is characterized by a S-shaped offset and a cross-sectional area change going from a semi-circle at the entrance to a full circle at the exit. The performance of the diffuser was quantified by the two parameters of primary concern in jet engine applications: Total pressure recovery and total pressure distortion at the fan face (i.e. the exit) calculated from the total pressure data measured inside the duct. Flat plate vortex generators (vg’s) were deployed in an attempt to alter the flow structure inside the diffuser and eliminate separation in order to realize improvements in the diffuser performance descriptors. It was readily observed that the presence of the offset had a very strong effect on the behavior of the flow, causing separation and strong secondary flows in the Sduct accompanied by total pressure recovery of approximately 90% and total pressure distortion at the fan face of 77% (normalized to dynamic pressure) for the base case without flow control. Installation of vg’s in the Sduct helped to decrease the distortion to about 11% in some cases and prevented flow separation. However, in all cases, it was not possible to improve the pressure recovery in the S-duct much beyond the 90% range for the base flow with no vg’s.

22 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202316
202225
2021127
2020147
2019153
2018128