Re: CONC.Reducer at Suction End of Pump

From: <Christopher>
Date: Mon Feb 19 2007 - 14:09:00 EST

On Feb 19, 2007, at 12:44 AM, waqas_314 wrote:

> i had heard somewhere that if we place an Concentric reducer at the
> inlet(suction) of a pump then there will be cavitation action.because
> there will be AIR POCKETS produce.

cavitation occurs in liquids when the local pressure drops below the vapor pressure of the fluid and small bubbles form. These aren't air pockets--they're vapor. At some point the pressure increases and the bubbles collapse suddenly causing impacts which damage the metal surface.
It's possible to get cavitation in a reducer under the right physical conditions, but cavitation is usually associated with high velocity and sudden changes on flow area leading to pressure drops.

Christopher Wright P.E. |"They couldn't hit an elephant at <a href="/group/PipingDesign/post?postID=tzk5AMG2bjwt3ua7g6opsJcmb0FloSUBgvclbnwln4u6E_DPZZrHGssj0hYEGeCYmQExltOA7RAzPQ">chrisw@skypoint.com</a> | this distance" (last words of Gen.

.......................................| John Sedgwick, Spotsylvania

1864)
<a href="http://www.skypoint.com/~chrisw/">http://www.skypoint.com/~chrisw/</a> Received on Mon Feb 19 14:09:00 2007