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Old   April 3, 2001, 13:18
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  #1
Dimitris
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I was wondering how is it possible to find the damage on the blades of a water pump. What to mesh, how to mesh, how to solve, etc.
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Old   April 3, 2001, 13:34
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John C. Chien
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(1). What kind of damage? Could you be more specific? (2). AS for the meshing, you can visit the websites of vendors specialized in turbomachinery mesh generation first to get some feeling.
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Old   April 3, 2001, 13:44
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Dimitris
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First of all I'd like you to mention to me some companies to check around their web pages. Secondly, when you try to pump water (For example) if the depth is too big (from 7-10 meters) their is a big possibility of boubles to appear (The so called cavernous). This think if I know correctly damages the pump.
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Old   April 3, 2001, 14:05
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andy
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This might help (taken from a recent posting here by ken elms):

http://www.ub.utwente.nl/webdocs/wb/1/t0000004.pdf

I believe (but may be wrong) ken also looks after a web page dedicated to pumps but cannot find the link. Anyone?
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Old   April 3, 2001, 14:35
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  #5
John C. Chien
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(1). I think you can find some pump mesh picutres at http://www.catalpa.net/ and some other sponsors website listed in the bottom of the home page of this cfd-online. (2). You can also try to visit ken elms' website on pumps, his e-mail is kenelms@fcmail.com (3). I am not sure whether you are talking about "cavitation in pump" or not.
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Old   April 4, 2001, 02:48
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Jing
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As I know, the damage on the blades could be caused by the cavitation and chemical or sand erosion. We deal with this kind of problem by eastablishing a cavitation or erosion model and predicting the damage on the blade based on the numerical results of the flowfield. By the way, the numerical model describing the damage should be a function of time.

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Old   April 4, 2001, 14:41
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Dimitris
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What you mean is that I have to solvea transient problem. What I don't know is the factor that represents the damage (For example, the drag of an airfoil can be found easily by integrating the sear stress around the airfoil). That's my basic problem. What factor is responsible for the damage from cavitation.
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Old   April 5, 2001, 03:02
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Jing
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Hi,

What I mean is not that you have to solve a transient problem. It is a transient or steady case is determinded by in which way you want to deal with the problem.

I am not clear about your problem. But I think there are two steps need to be done to estimate the cavitation damage.

1) simulation of the flowfield with cavitation here you can use transient or steady method, doesn't matter. But the position and surrounded flowfield of the cavitation should be resulted.

2)estimation of the cavitation damage the cavitation damage (I means the area and depth) should be a function of time, surrouded flowfield distribution and blade material (pump works more longer, then the damage is more deep). There are some empirical equations to describe it. Unforunately I don't have it on hand. Please try to find it out from literatures.

Good Luck!

Jing

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Old   April 6, 2001, 08:13
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ken elms
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I can only suggest you read these papers which may help in your tacling and understanding of the problems .

A PARAMETRIC STUDY OF THE CAVITATION INCEPTION BEHAVIOUR OF A MIXED-FLOW PUMP IMPELLER USING 3D POTENTIAL FLOW MODEL-ASME FLUIDS ENG JUNE 1997[FEDSM 1997]

AUTHOR M.J.VAN OS,JGH OP DE WOERD AND JB JONK.

ALSO CENTRIFUGAL PUMP PERFORMANCE DROP DUE TO LEADING EDGE CAVITATION:NUMERICAL PREDICTIONS COMPARED WITH MODEL TESTS. [JOURNAL OF FLUIDS ENGINEERING DEC 1998 VOL 120/705

GOOD LUCK WITH YOUR INVESTIGATION.

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