GE Ultrasonic flow meter
GE Ultrasonic flow meter
(OP)
I am using a GE ultrasonic flow meter that measures flow through 2 ultrasonic transducers. I have never used one like this before and it works good until the flow rate gets toward top end of scale. It is suppose to measure 650gal/min and I can not get above 425gal/min. It is showing signal strength and volecity but these values all jump around after approx 425gal/min. I am moving liquid at 200C of sodium metal and 5barg line pressure. I have instead of 10 times, I have 20 times pipe diameter before flow meter and 5 times after. This is 4" SS304L pipe and test loop holds about 20 gallons of liquid that simply circulates. Anyone who has any experience with this type of testing I would appreciate any thoughts as to trying to solve issue.





RE: GE Ultrasonic flow meter
RE: GE Ultrasonic flow meter
RE: GE Ultrasonic flow meter
Are the probe ends protruding into the flow, and is this the doppler type meter, that beams a signal along the flow axis?
RE: GE Ultrasonic flow meter
RE: GE Ultrasonic flow meter
RE: GE Ultrasonic flow meter
You have a succession of tight elbows. Possibly a flow straightener "eg crate" bundle or simple static mixer element, enough to break up the flow prior to the meter and far enough upstream so the flow can become more "organised" by the time it reaches the meter.
The other thing is, running at high temperatures, how good is the insulation? What are you using - calcium silicate? (In too many installations insulation is applied to protect operators and not to prevent significant heat loss.
The effects of poor insulation on high temperature installations with sensitive fluids can be profound and I have seen some bitumen installations that have suffered badly from an open window on a cold day close to a badly insulated pipe.
Temperature gradients may cause you to get some nice tunnelling effects with layers of fluid by the walls cooling, thickening and slowing and the flow increasingly down the centre of the pipeline.
This may mean you have quite a velocity differential across the pipe diameter and this may also lead to some unstable flow regimes at the meter at higher flow rates where the flow breaks up boundary layers briefly and which then re-establish themselves only to be broken up again.
Again, a static mixer may help this. Possibly Vortab or similar.
Not sure that GE should necessarily need liquid sodium experience to diagnose possible causes of flow measurement anomalies. They must know what causes such effects and then look back into the application to see if those causes could arise. But granted, experience of liquid sodium would speed up the diagnosis, so they may just be being cautious.
JMW
www.ViscoAnalyser.com
RE: GE Ultrasonic flow meter
Yes my 90-elbow are fairly tight and I will look into the vortab concept.
My fluid max volecity is about 11ft/s and meter is rated for max 40ft/s. When I loss signal strength, I also losssound speed, volecity and flow. So once signal strength drops there are no valid valves.
My time issue with any changes to loop is this, it takes me 5 days to drain loop of sodium, cool loop down, clean sodium out, fix issue, heat loop up, pressure and vacuum test and then fill loop. Trial an error is a long process and I try to make sure I can make as many changes ay once as I can. This is very different from my past where we never made more than one change at a time.