User:M.Saleem 1991

To understand the concepts of cavitation ,an important phenomenon in all hydraulic machine ,and  control measures for it as well as  its application In Chemical  Engineering. INTRODUCTION: Cavitation means that cavities or bubbles are forming in the liquid that we're pumping. These cavities form at the low pressure or suction side of the pump, causing several effects to happen all at once: •	The cavities or bubbles will collapse when they pass into the higher regions of pressure, causing noise, vibration, and damage to many of the components. •	We experience a loss in capacity. •	The pump can no longer build the same head (pressure) •	The pump's efficiency drops.

The cavities are form due to following basic reasons •	Vaporization               ( when pressure becomes too low, or its temperature too high. ) •	Internal   recirculation   (can  be found at the suction eye of the pump.) •	Flow turbulence              (Corrosion or obstructions can change the velocity of this liquid  ) •	The Vane Passing Syndrome  ( when the OD of   impeller passes too close to the pump  cutwater)

It may occur at: •	Behind the blades of high speed rotating propeller •	On any surface vibrating under water

Research on the cavitation under thermodynamic effects has generally been focused on obtaining correlations for temperature depression as a function of flow conditions and liquid properties.

The solution of the Navier-Stokes equations in combination with an algebraic turbulence model provides the details of the cavity geometry, while the temperature depression in the vicinity of the cavi-ty interface can be obtained to solve the energy equation. This research only considers the flow field information. the cavitation mass transfer equation under the thermodynamic effects is modified. This modified equation mainly considers the temperature variation, pressure pulsation and physical properties. .