b'Engineer Innovation | Process Industries65 m 600 (24) Flomaster allows the same model to be 2 run in steady and transient simulations 2900 m3/h (2.8m/s) without any simplifications. Therefore, h = 10 mthe user has full control to calibrate initial 10000 m3 1 states and thereby ensure that the maximum possible accuracy from Waste watertransient analyses is obtained. High ow rate, fast ow velocityDetected pressure amplitude Methodology to identify where pressurePartially mounted on pipe bridge 2measure 8 barg surge analysis is vital to safety Fast valve closure 1Real value may be higher (gauge inertia) Damage occuredForce on pipe supports80kN peak Process and pharma plants work withPipe partially left the bridge!multiple fluids some of which may be Figure 1: Real damage event in process industry supplied from external tank farms via long distance supply networks. There can be hundreds of such pipelines and high flow speeds can occur. To minimize effort,possibly formation of a more pragmatic approach is required to cavitation bubblepositive pressure signal valve0, v 0 identify the components that are critical to safety and require detailed analyses. The practical approach used to do this is0, v 0 closure summarized below:negative pressure signalPipes containing gas or vapor are in Figure 2: Pressure surge and cavitation phenomena general not as critical, with exceptions of condensing vapor, failure modes, reinforced pulsations, choking, etc.Short pipes within buildings are generally not critical. Exceptions can valve be fast closing valves or high flow 3000 m,80 mm speed lines.1.3 m/s25 m3/h closureFor each of the remaining set of pipes a systematic screening method is Valve completely Line Static Pressure Upstream of Ball Valveclosed packing applied, by means of a spread sheet. erasing effectFirst a reference peak pressure is 20 barg of reected signal obtained by adding the Joukowski 16 barg shock to the normal operating static pressureJoukowski pressure:12 shock8 barg Reference peak pressure ^4 barg p ref.= p operation+ p Jouk.0 barg 0 s3 s6 s9 s12 s15 s18 s21 s24 s This value is then compared to the time acceptable pressure ("p "), as acceptableFigure 3: Pressure path for fully developed surge defined by the pressure rating of the pipe. ^If p pfurther detailed ref.acceptableinvestigation by dynamic simulation is such, the solver is stable for even highlyrequired. If this condition is not true, complex networks and captures thefurther investigation may be avoided. relevant physical phenomena accurately. From a usability perspective, the modelsThe flow chart in figure 4 describes the are easy to organize into projects andprocedure from the screening down to same models can be used for both steadydetailed simulation. There are three exits, and dynamic analyses. This allows forat which the path can be successfully left:appropriate flow and velocity distribution to be calculated while accounting forExit 1: If the screening finds no critical multiple fittings. Accurate initial velocityreference peak pressure, no measure is distribution is critical to the accuracy ofrequired for this pipe.pressure surge calculation. For this reason any simplifications applied to the modelExit 2: If the reference peak pressure can may compromise the accuracy. Simcenterbe sufficiently reduced by simple means 52'