Cavitation sign

Air-crescent-sign and cavitation occur simultaneously with haematological reconstitution during the late phase of infection (Fig. 27.10) (Kim MJ et al. 2001). Therefore air-crescent and cavitation signs are known... 

Along with the sounds, evidence and signs of cavitation, there is a broad range of other information and signals available to the maintenance mechanic. Almost all mechanics have seen the gouge and scratch marks, and signs of heat on the pump when disassembled in the shop. Sadly, most mechanics are never trained to interpret these marks. 

Feedwater supply duties include checking and recording the demand for FW makeup and maintaining correct FW temperatures to prevent risks of pump cavitation and boiler thermal shock. Periodically checking deaerator performance and inspecting the FW pumps and lines for any signs of fouling or corrosion is also required. 

Pumps shall operate within beating temperature hmits as defined in paragraph 2.9.2.3 and shall not display signs of unfavorable operation, such as noise caused by cavitation. 

In practice, models that directly calculate cavitation and dispersion/repulsion tend to predict that both effects are quite large in magnitude, but witli opposite sign so that there is a large degree of cancellation. This suggests the unfortunate possibility that errors in the individual models may be larger than the net result. 

I once tried to increase the flow of jet fuel from a crude distillation column by opening the draw-off, flow-control valve. Opening the valve from 30 to 100 percent did not increase the flow of jet fuel at all. This is a sure sign of nozzle exit loss—or cavitation limits. To prove my point, I increased the level of liquid in the draw-off sump from 2 to 4 ft. Since flow is proportional to velocity and head is proportional to (veloc-... 

It is interesting that, upon rubber modification, the CET resin matrix can no longer form dilatation bands (18). Only rubber-particle cavitation and matrix shear yielding are detected. This observation implies that a dilatational stress component is required to trigger the formation of dilatation bands. In other words, upon rubber-particle cavitation, the dilatational stress component in the matrix is reduced. This suppresses the formation of dilatation bands. This conjecture finds support in the work of Glad (27), who investigated thin-film deformation of epoxy resins with various cross-link densities and could not find any signs of dilatation bands in his study. 

The signs of abnormal operation caused by cavitation are local knocking and a slight instability in pump parameters (current, pressure, flow), which can be detected from the control room. No local noise is generated apart from the noise of the pump motor forcing. 

Cavitation] [fluid vaporizes] /pump rpm too fast/suction resistance too high/ clogged suction line/suction pressure too low/liquid flowrate higher than de-sign/entrained gas. 

Fig. 6.80 Cavitation strain and total strain as a function of normalized beam height for creep a M = 0.165 N-m (80 MPa initial maximum stress), 1170 °C, 300 h b Af = 0.247 N-m (120 MPa initial maximum stress), 1170 °C, 142 h. The - - and — signs in this figure represent tensile and compressive stresses, respectively [5]. With kind permission of John Wiley and Sons...

In immuno-compromised hosts a peribronchial distribution (resulting in a tree-in-bud sign) of small, sometimes cavitated ill-defined nodules can be obtained due to miliar distribution (Goo and Im 2002 Van Dyck et al. 2003). Ganghopulmonary (primary) forms, however, present with In homogenous consohdation and necrotic mediastinal/hilar lymphadenopathy (Van Dyck et al. 2003). 

The pump was run under severe cavitation and surging conditions for 6 to 8 hours at various flow rates without any visible signs of cavitation damage on inspection afterward. 

The primary water pumps started to cavitate—a sign of low level in the pressurizer. However, the operators did not recognize what was going on—they still believed that they were facing a high-level situation. 

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