I agree that the "stall occures first. What happens next? If I tell guys my chiller is "stalling" it may not mean much. If it is "surging" I think more people will relate to that term. Undrestanding surge and its causes is the main idea.
turbo - if you don't mind, i'll be glad to have a copy
HI TURBOMASTER,HEY I WOULD BE INTERESTED IN READING THAT ABOUT WHAT YORK HAS TO SAY ABOUT IT.MY EMAIL IS IN MY PROFILE---THANKS PAT
I always liked this from Mcquay
Centrifugal compressors differ from positive displacement compressors (such as scroll,
reciprocating and screw). Centrifugals are aerodynamic or turbine type. They move gas by
converting kinetic energy to pressure energy. Positive displacement compressors encase a
quantity of refrigerant in a decreasing volume during the compression process. They provide
excellent lift characteristics. The advantage of centrifugal compressors is their high flow
rates capability and good efficiency characteristics.
The simple way to understand the principle is to imagine a ball on the end of a string. One
person swings the ball on the string. A second person is standing the second floor balcony.
If the person swinging the ball releases ball with enough angular momentum, the ball will fly
up to the person on the second floor balcony. The weight of the ball (molecular weight), the
length of the string (wheel diameter) and the rotational speed (rpm) affect the angular
I WILL SELL WORK,GENERATE BUSINESS, GO GET NEW CUSTOMERS!
YOU SHUT THE HELL UP AND QUIT RUNNING YOUR MOUTH!
Rotating stall is the condition that occurs when there's not enough mass flow of refrigerant through the impeller to displace the refgt that's already in the diffuser gap, so instead of having a nice, smooth flow on into the condenser, rotating "eddies" of gas set up in the diffuser gap. A lot of folks call this "low load surge", but actually it's just a very unstable gas flow off of the impeller and through the compressor. Mass flow rate drops due to a lot of things. The most prevalent time to see this condition is when the machine unloads (vanes, not VSD), and the cooling tower is not allowed to unload with it (condenser water temp is held towards design at the same time). Stall is the condition that occurs right before surge, but if you're in a condition that will cause a full-blown surge, you have to be real quick to hear it.
Surge is when the delta p (lift, measured in degrees) across the impeller becomes greater than the impeller can overcome, and there is a momentary reversal of gas flow through the impeller. That reversal is what creates the severe swing in current during a surge condition. Stall and surge are definitely related, but are two different things from an operational standpoint.
i wouldn't mind seeing the york info also i think my e-mail is in my profile thanks
Here is Yorks discription of stall detection on YK with VGD variable geometry diffuser
Arguing with your Boss is like wrestling with a pig in
After a while you realize that while you are getting
dirty, the pig is actually enjoying it.
It is not exactly cheating, I prefer to consider it
creative problem solving.
25 years ago we had Bob Hope , Steve Jobs , and Johnny Cash today we have no Hope no Jobs and no Cash !
I can fix broke but i can't fix stupid !
Ya'll got mail, hope that works OK. I'm not the brightest tool when it comes to sending stuff. My 19 year old son had to school me on the scanner.
Ditaw, my email program ain't liking your email for some reason.
thanks turbo. haven't had a chance to read it. worked late tonite (again)
klove - great way of putting the explanation to words