Valves antisurge

Attention to noise may be required beeause antisurge valves usually have large pressure drops. Appropriate valve style, noise attenuation trim, and in-line deviees, as well as attention to line veloeities and pipe sehedules, ean eliminate or minimize the noise. 

But, as we reduce N, we are moving toward the surge point in Fig. 28.3. If we try to save too much electricity, by forcing the FC to close too much, then the centrifugal compressor may be forced into surge. That is why we call the FC spillback valve the antisurge valve. 

Low suction flow. Open the antisurge valve. This allows gas from the discharge of the compressor to circulate back to the compressor suction. 

High suction temperature. Most installations will have the ability to inject a light hydrocarbon liquid upstream of the compressor s suction. This liquid vaporizes and, hence, cools the hot vapor flowing to the compressor suction. Typically, the vapor has overheated because the antisurge valve has been... 

INVESTIGATION ON PERFORMANCE OF TURBOCHARGED SPARK-IGNITION ENGINE EQUIPPED WITH ANTISURGE VALVE AND BYPASS FLOW CONTROL MECHANISM AT VARIOUS WORKING CONDITIONS... 

It should be noted that the choice of turbocharger has been carried out without considering antisurge valve and wastegate. 

In order to avoid surge occurrence in compressor, axial or radial one, antisurge valve is used usually. Various mechanisms have been presented for these valves which all of them are based on reduction of compressor downstream pressure and according to surge control line (to avoid surge occurrence). We use this line to compensate uncertainly in the measurements and delay in valve performance. There are some descriptions for this parameter that one of them has been shown in Eq. (3.8). 

FIGURE 3.12 Comparison of compressor performance curve in an engine cycle equipped to an antisurge valve. 

FIGURE 3.15 Mass flow rate variation of antisurge valve versus crank angle in engine speed of 1,800 rpm. 

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