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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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TL;DR: In this article, the effect of roughness on the flow coefficient of a triple eccentric butterfly valve with various valve opening degrees was investigated and the results showed that increases in the roughness height significantly increase the frictional pressure drop.
Abstract: Butterfly valves are used widely as flow controllers in many industrial applications. In order to design and select an appropriate valve for a particular application, it is important to predict correctly its flow coefficient. The flow coefficient of a valve can be affected by a number of factors. This study presents a numerical investigation of the effect of friction on the flow coefficient of a triple eccentric butterfly valve with various valve opening degrees. Since the Reynolds number and cavitation can affect the flow coefficient under certain conditions, these effects are discussed and analyzed based on previously reported experimental data before studying the effects of friction. Under the test conditions recommended in IEC 60534-2-3, it is found that the effects of the Reynolds number and cavitation are quite small and can be ignored. The flow coefficients obtained from numerical simulations that take into account friction are found to be in good agreement with the experimentally determined ones. The differences in the flow coefficients obtained from numerical simulations that consider friction and those that ignore it are discussed. There is a maximum difference of 17 % for a fully open valve. The results show that increases in the roughness height significantly increase the frictional pressure drop. The effect of the roughness height on the frictional pressure drop and total pressure drop can be fitted well using fitting functions for fixed opening degree. It is found that the effect of the roughness can cause the determined flow coefficient to be different from the actual value. Thus, the measured flow coefficients and pressure drops for such valves can be determined with accuracy through experimental techniques and numerical simulations that account for the effect of roughness.
29 citations
TL;DR: In this paper, two porous ceramic disks with different pore radii were arranged in series to mimic an asymmetric membrane and different interlayer pressures and fluxes were predicted and detected experimentally depending on the flow direction.
29 citations
TL;DR: In this article, dynamic surface tension measurements of molten aluminium have been carried out under different monitored oxygen partial pressures in the temperature range 873 −1323 K with the aim of experimentally confirming the behaviour of molten metals in the presence of traces of oxygen as predicted by theoretical models.
29 citations
01 Jun 1992
TL;DR: In this paper, a rotatable low solidity vaned diffuser (RLSD) was installed in a single stage test vehicle consisting of a pseudo-return channel inlet, a subsonic centrifugal impeller (approx. 2:1 pressure ratio), the rotatable diffuser, a return channel and a dump collector.
Abstract: This paper reviews test results from a rotatable low solidity vaned diffuser (RLSD). The device was installed in a single stage test vehicle consisting of a pseudo-return channel inlet, a subsonic centrifugal impeller (approx. 2:1 pressure ratio), the rotatable diffuser, a return channel and a dump collector. Static taps, total pressure probes, and thermocouples were located in critical areas throughout the stage. Manual traverse probes measured the pressure and angle profiles at RLSD leading and trailing edges. Results for various stagger angles, leading edge radius ratios, etc. are presented in terms of pressure recovery (Cp) and loss coefficient (LC). Comments are made regarding the applicability of the RLSD in production units.Copyright © 1992 by ASME
28 citations
TL;DR: In this article, the second order state constant of HO2 + HO2 → H2O2 + O2 (2k1) was determined using flash photolysis techniques, over the temperature range 298-510 K, in a nitrogen diluent at a total pressure of 700 Torr.
28 citations