Topic
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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TL;DR: In this article, the effects of gap height and tip geometry on heat transfer distribution over the tip surface of a HPT first-stage rotor blade were explored. But the authors did not consider the effect of partial burning of the squealer.
Abstract: The present study explores the effects of gap height and tip geometry on heat transfer distribution over the tip surface of a HPT first-stage rotor blade. The pressure ratio (inlet total pressure to exit static pressure for the cascade) used was 1.2, and the experiments were run in a blow-down test rig with a four-blade linear cascade. A transient liquid crystal technique was used to obtain the tip heat transfer distributions. Pressure measurements were made on the blade surface and on the shroud for different tip geometries and tip gaps to characterize the leakage flow and understand the heat transfer distributions. Two different tip gap-to-blade span ratios of 1% and 2.6% are investigated for a plane tip, and a deep squealer with depth-to-blade span ratio of 0.0416. For a shallow squealer with depth-to-blade span ratio of 0.0104, only 1% gap-to-span ratio is considered. The presence of the squealer alters the tip gap flow field significantly and produces lower overall heat transfer coefficients. The effects of different partial squealer arrangements are also investigated for the shallow squealer depth. These simulate partial burning off of the squealer in real turbine blades. Results show that some partial burning of squealers may be beneficial in terms of overall reduction in heat transfer coefficients over the tip surface.
57 citations
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TL;DR: In this paper, the effects of tip shape on the secondary flow and total pressure loss in a turbine cascade have been investigated experimentally and a total of 11 tip shapes including plane, single or double squealer, dimpled, chamfered, and grooved tips were tested.
57 citations
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TL;DR: In this paper, the relative proportions of atomic and molecular nitrogen in the cathode sheath and plasma regions of these discharges operated at −2 kV cathode bias in the range 0.1-10 Pa.
57 citations
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TL;DR: In this article, the effect of the total gas pressure on the deposition of microcrystalline thin films form highly diluted silane in hydrogen discharges was carried out at two different frequencies.
Abstract: An investigation of the effect of the total gas pressure on the deposition of microcrystalline thin films form highly diluted silane in hydrogen discharges was carried out at two different frequencies. The study was performed in conditions of constant power dissipation and constant silane partial pressure in the discharge while using a series of plasma diagnostics as electrical, optical, mass spectrometric, and in situ deposition rate measurements together with a simulator of the gas phase and the surface chemistry of SiH4∕H2 discharges. The results show that both the electron density and energy are affected by the change of the total pressure and the frequency. This in turn influences the rate of high energy electron–SiH4 dissociative processes and the total SiH4 consumption, which are favored by the frequency increase for most of the pressures. Furthermore, frequency was found to have the weakest effect on the deposition rate that was enhanced at 27.12MHz only for the lowest pressure of 1Torr. On the ot...
57 citations
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TL;DR: In this paper, the classical equations of two-phase flow in a porous media are solved together with two transport equations representing the leaching process, where the principal variables are the total pressure, the total flux and the saturation of the liquid phase.
57 citations