Capillarity is the phenomenon where the interaction between a liquid and a solid results in liquid molecules escaping from the surface into the gas phase, lowering the vapor pressure. The vapor pressure is the pressure exerted by a vapor in equilibrium with its liquid state. A lower vapor pressure results in a lower boiling temperature, while a higher vapor pressure increases the boiling temperature. Cavitation occurs when the pressure of a flowing liquid falls below its vapor pressure, resulting in the formation of vapor bubbles. There are two types of cavitation - inertial cavitation, where a bubble rapidly collapses producing a shock wave, and incipient cavitation, which is the beginning stage of cavitation before becoming destructive.

1. Capillarity
By
Rampal Singh Ojha
Assistant Professor
Department of Mechanical Engineering, Rai University
B.E.(Mechanical),M.tech(Production)
GATE 2011,2012,2015

2. WATER
HEAT
Molecules escaping
from surface
Vapour Pressure – the pressure exerted by a vapor in
equilibrium with its liquid state.
 • Liquid molecules at the surface escape into the gas phase.

3. VAPOUR PRESSURE
• Lower the vaour pressure lower will be boiling temperature
• Higher the vaour pressure higher will be boiling temperature

4. CAVITATION
• Cavitation is defined as the phenomenon of formation of vapor
bubbles of a flowing liquid in a region where the pressure of the
liquid falls below its vapour pressure.
• Cavitation is usually divided into two classes of behavior: inertial (or
transient) cavitation and Incipient cavitation. Inertial cavitation is the
process where a void or bubble in a liquid rapidly collapses, producing a
shock wave.
• Incipient cavitation is the point at where cavitation begins, but has
not reached a destructive state