Hydroic Cavitation Research Paper

Abstract

Now a day’s hydrodynamic cavitation is being explored by many researchers all around the world because it is found to be more energy efficient and easy to scale up as compared to its counterpart known as acoustic cavitation which is tends to be more energy consuming technology. The cavitation phenomena causes the release of highly reactive free radicals and the large magnitude of energy during a violent collapse of the cavities and thus initiated the various chemical and physical processes in different area of applications. This review work provides an overview of application of hydrodynamic cavitation in various chemical processes such as chemical synthesis, biodiesel synthesis and wastewater treatment and physical processes such

The chemical change takes place due to the cavitation induced by the passage of sound waves which is known as Sonochemistry [3]. Hydrodynamic cavitation: Cavitation is produced by pressure variations, which is obtained using geometry of the system creating velocity variation. The variation of pressure through a constriction channel such as venturi, orifice etc. with different geometry leads to the generation of cavities and the induced effects can produce physical and chemical changes with this mode of

Hydrodynamic cavitation

A newly established technique in the last decade which is continuing in proving its ability in large scale operation and found as a substitute towards the other technique such as acoustic cavitation. The technique works in hydraulic fashion where the generation of cavitation is done by passing the liquid through proper constriction such as orifice plate or a venturi.

In hydrodynamic cavitation, cavities are formed due to pressure variation in the flowing liquid caused by a change in flow area such as venturi and orifice plate. When the liquid passes through the geometry of the constriction, the kinetic energy of the liquid increases at the expense of pressure and at the sufficient throttling, the pressure near the vena contracta falls below the vapor pressure of the liquids where the liquid flashes and generating numerous vapor cavities. Subsequently, as the liquid jet expands the velocity decreases and the pressure recovers in downstream, resulting in the collapse of the cavities. A creation of a very high turbulence befalls inside the device at downstream section where the desired physical and chemical transformation occurs. This cavitational intensity which brings out these physical and chemical changes is very much depends on the geometry of the devices and the flow condition of the liquid medium. A localized hot spot region generates with temperature of the order of 10,000 K, and pressures of about 1000 bar over a microsecond interval due to the