1、翻译 Sealed building drainage and vent systems an application of active air pressure transient control and suppression Abstract The introduction of sealed building drainage and vent systems is considered a viable proposition for complex buildings due to the use of active pressure transient control and
2、 suppression in the form of air admittance valves and positive air pressure attenuators coupled with the interconnection of the networks vertical stacks. This paper presents a simulation based on a four-stack network that illustrates flow mechanisms within the pipework following both appliance disch
3、arge generated, and sewer imposed, transients. This simulation identifies the role of the active air pressure control devices in maintaining system pressures at levels that do not deplete trap seals. Further simulation exercises would be necessary to provide proof of concept, and it would be advanta
4、geous to parallel these with laboratory, and possibly site, trials for validation purposes. Despite this caution the initial results are highly encouraging and are sufficient to confirm the potential to provide definite benefits in terms of enhanced system security as well as increased reliability a
5、nd reduced installation and material costs. Keywords: Active control； Trap retention； Transient propagation Nomenclature C+- characteristic equations c wave speed, m/s D branch or stack diameter, m f friction factor, UK definition via Darcy h=4fLu2/2Dg g acceleration due to gravity, m/s2 K loss coef
6、ficient L pipe length, m p air pressure, N/m2 t time, s u mean air velocity, m/s x distance, m ratio specific heats h head loss, m p pressure difference, N/m2 t time step, s x internodal length, m density, kg/m3 Suffix A appliance side of trap B branch local conditions at node T trap atm atmospheric
7、 pressure F friction R room S system side of trap w water Article Outline Nomenclature 1. Introductionair pressure transient control and suppression 2. Mathematical basis for the simulation of transient propagation in multi-stack building drainage networks 3. Role of diversity in system operation 4. Simulation of the operation of a multi-stack sealed building drainage and vent system 5. Simulation sign conventions 6. Water discharge to the network
