Total pressure

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

A new correlation for pressure drop of packed column

Abstract: By the use of the experimental data of many previous studies, a new correlation for the pressure drop of a packed column was obtained in this work. The total pressure drop is expressed as the sum of the dry pressure drop and the wet pressure drop. The dry pressure drop originates mainly from the friction of gas rising through the void of the packed bed, and is expressed by the Fanning equation. The wet pressure drop originates from the increase in net gas velocity because of the smaller void of the packed bed owing to the liquid holdup, and therefore it is expressed as a function of liquid holdup, gas velocity, etc. The liquid holdup consists of static and dynamic holdups, and is correlated separately.

Method and apparatus for controlling a gas turbine engine

Abstract: A gas turbine engine control for an engine which experiences airflow distortion at the engine inlet face plane uses a static pressure measurement upstream of the face plane along with a corrected rotor speed to generate a signal indicative of the average total pressure at the engine face plane. This signal is combined with a total pressure signal from elsewhere in the engine to generate a pressure ratio signal which is compared to the scheduled pressure ratio for the current operating conditions. Control logic then adjusts either the fuel flow rate to the burners or the area of the exhaust nozzle in response to the difference between these pressure ratios.

Combined pressure and temperature distortion effects on internal flow of a turbofan engine

Abstract: An additional data base for improving and verifying a computer simulation developed by an engine manufacturer was obtained. The multisegment parallel compressor simulation was designed to predict the effects of steady-state circumferential inlet total-pressure and total-temperature distortions on the flows into and through a turbofan compression system. It also predicts the degree of distortion that will result in surge of the compressor. The effect of combined 180 deg square-wave distortion patterns of total pressure and total temperature in various relative positions is reported. The observed effects of the combined distortion on a unitary bypass ratio turbofan engine are presented in terms of total and static pressure profiles and total temperature profiles at stations ahead of the inlet guide vanes as well as through the fan-compressor system. These observed profiles are compared with those predicted by the complex multisegment model. The effects of relative position of the two components comprising the combined distortion on the degree resulting in surge are discussed. Certain relative positions required less combined distortion than either a temperature or pressure distortion by itself.

Dehydration of calcium hydrogen phosphate dihydrate

Abstract: The dehydration of CaHPO4,2H2O has been studied isothermally between 409 and 537 K and over a range of partial pressures of water vapour between 1·3 cN m–2 and 6·0 kN m–2 at a total pressure of 1 atm. The rate of dehydration is controlled by diffusion of water, and below 478 K the activation energy is 190 kJ mol–1 and this value is not affected by the partial pressure of water vapour. However, above 478 K the activation energy drops markedly and is then affected by partial pressure of water vapour. Some evidence has been obtained for the formation of a monohydrate as an intermediate and, while this is not conclusive, this postulate helps to clarify the results of previous work.