Erosion : 유체의 빠른 운동에너지(속도)에 의한 장치/노즐/파이프 등의 침식, 배관에 가해지는 반복적인 충격은,
빠른 속도와 양의 충격으로 쇠를 자르는 물분사절단과 같은 원리임.
Erosion의 설계 기준은 일반적으로 Rho-V-2의 Momentum 계수로 판단함.
Rho V2 :
- Rho V2 is typical measurement for momentum, indirectly the kinetic energy of moving fluid.
- many old design, many designer focus on velocity as major factor in kinetic energy. However, nowadays designer will take into account of fluid density as density also play important rule in defining the kinetic energy especially fluid carrying liquid, heavy metal, solid, etc.
- In line, the kinetic energy is limited so that the vibration, erosion, corrosion, surge, noise, etc is within a "reasonable" range (subject to company and designer...). In gravity separator (believe your "vessel" mean separator), the kinetic energy is will distributed to reduce breakage of liquid phase, re-entrainment and allow sufficient time for gravity force to act on heavy component (liquid phase).
- Heat Exchanger :
SHELL SIDE IMPINGEMENT PROTECTION REQUIREMENTS
An impingement plate, or other means to protect the tube bundle against impinging fluids,
shall be provided when entrance line values of Rho-V2 exceed the following:
non-abrasive, single phase fluids : 1500 (2232)
all other liquids, including a liquid at its boiling point : 500 (744)
all other gases and vapors, including all nominally saturated vapors, and for liquid vapor
mixtures, impingement protection is required.
SHELL OR BUNDLE ENTRANCE AND EXIT AREAS
In no case shall the shell or bundle entrance or exit area produce a value of p V2 in excess of
4,000 (5953) where V is the linear velocity of the fluid in feet per second (meters per second)
and P is its density in pounds per cubic foot (kilograms per cubic meter).
TUBE SIDE
Consideration shall be given to the need for special devices to prevent erosion of the tube
ends under the following conditions:
(1) Use of an axial inlet nozzle.
(2) Liquid p V a is in excess of 6000 (8928) where V is the linear velocity in feet per second
(meter per second), and p is its density in pounds per cubic foot (kilograms per cubic
meter).
TEMA- RCB4.6