Pipe Network Fluid Flow Analysis Systems PipeNet Standard is a powerful tool in the design of single phase steady flow of fluids in pipes. It provides a quick and cost-effective means of designing real life problems. PipeNet Transient provides a speedy and cost-effective means of in-house rigorous transient analysis. The Transient Module can be used for predicting pressure surges, calculating hydraulic transient forces or even modelling control systems in flow networks PipeNet Spray/Sprinkler is a powerful tool in the design of fixed fire-protection systems complying with NFPA and FOC rules. It can be used to design deluge, ringmain, sprinkler and foam solution systems for offshore platforms, refineries, petrochemical and chemical plants PipeNet Standard Networks Networks can be defined from a wide choice of elements-pipes, ducts, nozzles, pumps/fans, filters, non-return valves, control valves, leaks, fixed pressure drops, orifice plates, properties and specifications. PIPENET has built-in data of fittings (Crane), gases, steam (IFC67 standard) and pipe schedules (ANSI, JIN and DIN). Users can also create their own pump, pipe schedule, control valve, fittings and fluids data libraries that can be used in any network. PIPENET allows the properties of the fluid to be constant or to vary in the network system. Fittings Multiple fittings can be inserted on a pipe and it is not necessary to treat them as separate entities. They are simply defined as attributes of a pipe. This is a powerful feature of PIPENET. Schematic Capabilities and On-line Help A network can be defined using schematic or text input. However, a text input network can also be displayed using the schematic. Results can also be displayed on the schematic. Online help is also available for more information on the features of PIPENET. Pipe Sizing and Blocked and Broken Pipes PIPENET has very powerful pipe sizing capabilities. It Can select standard nominal bores from user-defined or built-in pipe schedule data. A blocked or broken pipe can also be modelled in network. Cavitation The program will detect and report the likely occurrence of both deaeration and vaporisation cavitation. Orifice Plates Restriction Orifice plates can be modelled in compliance with Crane, Heriot-watt and    BS 1042, taking into account downstream pressure recovery. Given the pressure drop the orifice diameter is determined, and vice-versa. Modelling of Gases and Low-Pressure Gases These can be modelled using standard pressure loss correlations and correction factors,  making the module suitable for the design of gas distribution systems. Filters A filter is available for use where accurate modelling is required. On the other hand, filters can simply be modelled as fittings Leaks This is a powerful feature of the program and is particularly useful for flow analysis of ventilation systems where the handing of leaks is very important. Leaks are modelled in accordance with the requirements of BS5588. Leaks may be defined as between two nodes of a network (for instance to represent a leak around a door between rooms) or to the atmosphere. Control Valves This regulates flow or pressure in a network. The valve setting can be specified by the user or based on a sensor - pressure at a node, flow in a pipe or pressure difference between two nodes. Hydraulic Gradient Capability Hydraulic gradient capability calculations can be performed for incompressible fluids. Nozzles can be Modelled using Fundamental Equations of Flow Ambient Pressure Correction Particularly used in ventilation system calculations involving tall chimney stacks, automatic correction for the variation in ambient pressure with height is available. Output Output reports can be created using Word, Write or PIPENET Output Browser. Pump/Fan A standard PIPENET pre-processor is provided for the creation of libraries of performance characteristics. These can be readily accessed to include pumps/fans in networks. A given pump type need therefore be input to the module only once for it to be available for repeated use in different network designs. Pumps, including booster pumps, can be connected in series or parallel at any point in the network. [Top to this page] PipeNet Transient Built-in Element Models The following range of element models is available at present í Pipes í Pumps:Simple pump, Turbo pump í Valves: Operating valve, non-return valve, check valve, fluid damped check valve, liquid surge relief valve, regulator valve, inertial check valve. í Tanks:Accumulator tank, simple tank, surge tank í Vacuum breaker / Air release valve í Caissons í Control Systems: Pressure of Flow sensor, PID controller, Transfer function New models can be developed if required. Fittings Multiple fittings can be inserted on a pipe and it is not necessary to treat them as separate entities. They are simply defined as attributes of a pipe. This is a powerful feature of PIPENET. Time Operation of Valves The operating valve model can be used to represent a manual valve or a control valve. In the case of a manual valve, its operation would be directly specified by a user-defined boundary condition. In the case of a control valve, the operation would be defined by a signal from the control loop. Operation of Pumps (Simple or Turbo) The pressure increase provided by a simple pump depends on its speed and performance curve. The performance curve can be entered and saved as library. The pump speed is specified directly or by a signal from the control loop. The turbo pump can additionally handle the 'spin down' due to pump failure. Control Systems Control systems allow components such as pumps or valves to react to changes in pressure or flowrate in some part of the network. A sensor measures an instantaneous reading for pressure or flowrate, which is converted to a signal for the controlled device by means of a PID controller. Transfer functions can also be included in the control loop to model the dynamics of the sensor and the controlled device. Hydraulic Transient Forces Pipework can experience significant stresses and movements, or even sustain damage, due to fluid transient phenomena such as water hammer. PIPENET can calculate hydraulic transient forces and these can be read by pipe stress or structural analysis programs for further processing. Initial Conditions PIPENET can automatically generate the initial steady state solution. For cases where the starting point is not steady state, the user can supply own starting condition. Stationary Initial Condition Often a pipe network system would start from a stationary condition where the flow is zero throughout the system. It is possible to do this automatically. Vapour Cavitation Modelling Under transient flow conditions pipework can locally experience very low pressures. Generally these would be cyclic in nature. Constant formation and collapse of vapour cavities would accompany this phenomenon in cycles. PIPENET can model this. Automatic Calculation of Wave Speed and Time Step Under transient flow conditions, the effect of a disturbance makes itself felt throughout the system in the form of waves. The wave speed depends on parameters such as the modulus of elasticity of the pipe material, diameter, wall thickness, the Poisson's ratio and the compressibility of the fluid. The wave speed is of fundamental importance, and PIPENET can calculate it automatically. The program can also determine the time step for calculation automatically. The user can optionally specify both the wave speed and the time step. Tabular Output Typically, a large amount of calculated results would be produced by transient analysis. For this reason, the Transient module allows the user to define which variables are to be output and in what format. Graphical Output While tabular output is useful for a thorough analysis, graphical output can be used to get a quick overview. The Transient module allows the user to output selected variables graphically. The graphs can also be viewed as movies in real time. Forces Output The force-time history can be output in the form of a forces file. This file is specifically intended for further processing by pipe stress or structural analysis program. Functions available for Boundary Conditions The following functions may be used for specifying the boundary conditions. (These are time dependent.) í Constant í Power Ramp í Sine Wave í Exponential í Damped Sine Wave í Asymmetric Pulse í Profile - linear, step or cubic [Top to this page] PipeNet Spray/Sprinkler Network Networks can be defined from a wide choice of elements - pipes and fittings, nozzles, deluge valves, pumps/fans, filters, non-return valves, orifice plates, special equipment items, specifications and overboard dump valves. PipeNet has built-in data of fittings, pipe linings and pipe schedules. Users can also create their own pump, pipe schedule, pipe lining, nozzle and deluge valve data libraries that can be used in any network. Fittings Multiple fittings can be inserted on a pipe and it is not necessary to treat them as separate entities. They are simply defined as attributes of a pipe. This is a powerful feature of PipeNet. Schematic Capabilities and On-line Help A network can be defined using schematic or text input. However, a text input network can also be displayed using the schematic. Results can also be displayed on the schematic. On-line help is also available for more information on the features of PipeNet. Ringmain Capabilities Fire pumps (including booster pumps) may be connected in series or in parallel anywhere in the network. One or more of them may be operating in given scenario, and it is easy to switch pumps on and off. For ringmain systems, the program handles the following tasks: í pump selection calculations using manufacturer's pump data í connecting pumps or booster pumps in series or in parallel at any point in the network í modelling of conventional deluge valves in addition to constant flow deluge valves í attachment of monitors and hydrants í performing case studies with different fire scenarios í use of lined and unlined pipes in the same system í modelling operation of isolation valves í connecting loops, grids and trees in any combination í modelling of breaks and blocks in pipework Deluge Valves Deluge valves may be of conventional "clack" shut type or "constant flow" type. Monitors and hydrants may be attached anywhere in the network. Loops, grids and trees may be incorporated in any combination. Lined and unlined pipes can be used in the same system. Pump selection calculations can be performed or manufacturer's data can be used to model the exact behaviour of the system once a pump has been selected. The module makes it possible to perform cases studies with different fire scenarios. Breaks and blocks in the pipework may be modelled with ease. Deluge System Capabilities A powerful range of alternative calculation types is available. The Program can automatically identify the most remote nozzle and set its flow rate or the average density option may be chosen. The user may even specify the flow rate or flow density at a selected nozzle, or the available inlet pressure or flow rate. Orifice plates may be sized to balance the pressure required by the deluge system and the pressure available in the ringmain. For deluge systems the program can handle. í automatic identification of the most remote nozzle and setting its flow rate í sizing orifice plates to match the pressure required by the deluge system í specifying the flow rate or the flow density at a specific nozzle í specifying the available inlet pressure í selecting the average density option Pipe Schedule Pipes may be lined or unlined, selected from eight built-in pipe schedules and three pipe linings. Alternatively, users can set up their own pipe schedule and lining data. Pipe sizes can be referred to by nominal or external diameters. A network can include several different lined and unlined pipe types. Pipe Sizing The user may leave some or all pipe sizes unspecified. PIPENET will automatically suggest appropriate pipe sizes based on the user selected pipe schedule Orifice Plates Restriction Orifice plates can be modelled in compliance with Crane, Heriot-watt and BS1042, taking into account downstream pressure recovery. Given the pressure drop the orifice diameter is determined, and vice-versa. Remote Nozzle Calculation Calculations can match the minimum flow rate required at the nozzle that is hydraulically most remote. Nozzles may also be switched on or off individually or in banks. Materials Take-Off Materials take-off tables can also be produced for weight and cost estimation purposes. Output Output reports can be created using Word, Write or PIPENET Output Browser. Pump/Fan A standard PIPENET pre-processor is provided for the creation of libraries of performance characteristics. These can be readily accessed to include pumps, fans etc. in networks. A given pump type need therefore be input to the module only once for it to be available for repeated use in different network designs. [Top to this page]