Starting transients of flue organ pipes in relation to pressure rise time

1992 ◽  
Vol 91 (4) ◽  
pp. 2190-2202 ◽  
Author(s):  
A. W. Nolle ◽  
T. L. Finch
Keyword(s):  
Rise Time ◽  
Pressure Rise ◽  
Organ Pipes

Gaseous Deflagration in Piping: Part 2 — Proposed Methods and Code Acceptance Criteria

2017 ◽  
Author(s):  
John C. Minichiello ◽  
Thomas C. Ligon ◽  
David J. Gross
Keyword(s):  
Rise Time ◽  
Lower Energy ◽  
Waste Treatment ◽  
Pressure Rise ◽  
Piping System ◽  
Frequent Event ◽  
Piping Systems ◽  
Hydrogen Accumulation ◽  
Induced Stresses ◽  
Detonation Loading

This paper proposes Piping Code rules to address the effects of hydrogen deflagrations inside piping. Previous work proposed a set of criteria for piping subject to detonation loading [PVP2012-78519, PVP2012-78525]. This paper provides criteria to evaluate the effect of deflagrations, which typically have a slower rise time and lower energy, inside the piping. These deflagration criteria, coupled with the previously cited detonation criteria, are being used at the Hanford Tank Waste Treatment and Immobilization Plant to evaluate piping systems subject to hydrogen accumulation. The previous papers did not investigate or propose criteria for deflagrations, as these were known to have lower pressures and slower pressure rise times, but are still of some significance for piping design. Recent work has shown that there exists a scenario in which the deflagration loading may be very significant: deflagrations in small gas pockets surrounded by large waste slugs. Depending on the assumptions used to develop the loading, the unbalanced forces on piping segments in a long piping system can become high during a deflagration event. Thus, for the set of criteria chosen for deflagration, the deflagration event may become the limiting event, especially if it is the more frequent event. The criteria proposed need to recognize this scenario and guide the user to possible solutions. This paper presents the original methodology for evaluating these “slug” events, briefly discusses the recent testing and theory being pursued to reduce the effect of the loading [PVP2015-45970, PVP2016-63260, PVP2016-63262], and then proposes criteria for evaluating deflagration induced stresses and loads.

Effect of pressure rise time on tidal volume and gas exchange during pressure control ventilation

2000 ◽  
Vol 48 (5) ◽  
pp. 766
Author(s):  
Byung O Jeong ◽  
Youn Suck Koh ◽  
Tae Sun Shim ◽  
Sang Do Lee ◽  
Woo Sung Kim ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Tidal Volume ◽  
Rise Time ◽  
Pressure Rise ◽  
Pressure Control ◽  
Control Ventilation ◽  
Pressure Control Ventilation ◽  
Effect Of Pressure

Effect of pressure rise time on ventilator parameters and gas exchange during neonatal ventilation

2020 ◽  
Vol 55 (5) ◽  
pp. 1131-1138 ◽  
Author(s):  
David Chong ◽  
Sabrina Kayser ◽  
Eniko Szakmar ◽  
Colin J. Morley ◽  
Gusztav Belteki
Keyword(s):  
Gas Exchange ◽  
Rise Time ◽  
Pressure Rise ◽  
Effect Of Pressure ◽  
Neonatal Ventilation

Possibilistic Analysis of Structural Systems Subjected to Blast Loads

2003 ◽  
Author(s):  
Hari B. Kanegaonkar
Keyword(s):  
Pulse Duration ◽  
Rise Time ◽  
Peak Pressure ◽  
Pressure Rise ◽  
Structural Response ◽  
Offshore Structures ◽  
Blast Loads ◽  
Safety Level ◽  
Ignition Point ◽  
Blast Pulse

The accidental release of the hydrocarbons and the possibility of resulting explosion have to be taken into account while designing the topside systems of the offshore structures. Determination of design explosion loads for the topside structures is a complex task since it involves several sources of uncertainty. Dimensioning of blast loads is important in achieving the desired safety level against the structural failure and related consequences. The design loads must incorporate uncertainties due to variability in the ignition point location, the type of ignition source, the volume of the gas released and the characteristics of the gas cloud etc. These uncertainties which are not statistical in nature may not be categorised as random or probabilistic but are cognitive and fuzzy in nature. The probabilistic framework for structural analysis subjected to blast loads could be quite cumbersome due to high number of uncertain variables and complex interdependency. The uncertainty in the load and corresponding uncertainty in the structural response can either be predicted from variations in the uncertain load parameters — a sensitivity evaluation or through a compact “possibilistic analysis”. The blast loads are usually defined as a triangular pulse through peak pressure, rise time and the blast pulse duration as the parameters. In the present investigation, the parameters in the triangular blast load description are assumed fuzzy. The peak pressure, rise time and blast pulse duration are defined using triangular fuzzy numbers. The possibilistic dynamic response of simple structural system — beam — used in the blast wall is obtained using single-degree of freedom approximation. It is shown that the possibilistic response provides rational decision making tool to arrive at desired safety level.

Sign in / Sign up

Export Citation Format

Share Document