Hydraulic calculation of dissipating outfalls

Summary

Recently, significant attention has been paid to the environmental issues in the reconstruction, upgrade, and construction of wastewater treatment facilities in the Russian Federation. In these instances, estimating the capacity (performance) of the final element in the treatment system, i. e. the discharge of effluents into a water body is obligatory. Calculating dissipating outfalls presents certain challenges, since this issue has received insufficient attention so far. Making hydraulic calculations of a dissipating outfall is proposed as not a calculation of one single element – the head – but of the entire system, i. e. supply and distribution pipelines, and all the existing heads (openings). Addressing this problem lies in solving a system of algebraic nonlinear equations describing flow distribution with variable withdrawal rates in the dissipating outfall under consideration. Consequently, the discharge rates through each head and the piezometric head values at all the outfall assemblies are determined. The proposed mathematical model of a dissipating outfall provides for not only estimating the functionality of an existing or planned outfall but also, in case of a damage (rupture) in the underwater part of the outfall, determining its parameters, i. e. the orifice area and the rate of the flow entering the watercourse through it. By analogy with pumps, the concept of a head and rate specification is introduced, providing for the use of one parameter (flow rate or head at the initial outfall assembly) to determine the other parameter eliminating the hydraulic calculation of the entire outfall. An example of a hydraulic calculation of a dissipating outfall with an estimation of the operating parameters is provided.

Key words

hydraulic design , pressure losses , distribution pipeline , headwall , variable abstraction , effluent discharge into a water body , dissipating outfall

Hydraulic calculation of automatic firefighting systems
combined with internal fire water pipeline system

Summary

In recent decades the construction of large buildings has risen sharply: shopping and entertainment centers, multifunctional high-rise buildings for residential and public purposes with underground parking lots, storage facilities for the storage of combustible materials. During construction finishing materials are often used that emit toxic substances if ignition occurs. Fires can result in fatalities and substantial material losses. For the fire safety of buildings and structures the use of firefighting water supply – both outdoor and internal is most effective. Due to the inability to provide for outdoor firefighting of a large part of the premises of the upper floors of high-rise buildings, the effectiveness and reliability of internal firefighting systems is of particular importance. Water consumption for fire water supply can be 200 l/s or more. To supply water in such a volume to the fire points, effective internal fire water supply systems are required: automatic firefighting systems (sprinkler and deluge), internal fire water pipelines, deluge water curtains. Combined internal firefighting systems include automatic firefighting installations and internal firefighting water pipeline. The method of hydraulic calculation of each of these systems is available in the regulatory and specialized literature. However, in the process of hydraulic calculations of combined (integrated) firefighting water supply systems, their essential features should be taken into account. In this regard, a mathematical model of flow distribution in automatic firefighting systems combined with an internal fire water pipeline system is considered. The technique of hydraulic calculation of arbitrary combined firefighting water supply systems is given. The proposed model allows you to get an actual value of water abstraction through nozzles (sprayers) and hand control branch pipes.

Key words

pressure , head , hydraulic design , water curtain , automatic firefighting installations , internal fire water pipeline , flow distribution task , variable abstraction