Chapter 3 Water in Motion: Hydrokinetics Flashcards
Hydrokinetics
study of water in motion
What is Bernoulli’s theorem?
In a steady flow without friction, the sum of the velocity head, pressure head , and elevation head is constant for any incompressible fluid particle throughout its course….the total pressure is the same at any point within the system
how does the principle of conservation of matter relate to hydraulics
In hydraulics, this principle means that what goes into one end of a pipe/hose system must come out the other end
the principles of water flow in piping or hose systems
Principle 1. if the pipe/hose size remains constant, water velocity within the system will be constant
Principle 2. an increase in pipe/hose diameter will result in a reduction in water velocity
Principal 3. a reduction in pipe/hose diameter will result in an increase in water velocity
Principle 4. if pipe/hose size remains constant, water flowing uphill will travel at the same velocity as water flowing downhill
head refers to the height water supply over discharge orifice, how do you convert head in feet, to head pressure?
by dividing the number of feet by 2.31
head pressure=h/2.31
static pressure
stored potential energy to force water through pipes, fittings, fire hoses, and adapters
normal operating pressure
pressure found in the water distribution system during normal consumption demands
residual pressure
part of the total available pressure not used to overcome friction loss of gravity while forcing water through pipes, fittings, firehouses, and adapters
flow pressure
forward velocity pressure created and a discharge opening while water is flowing
first principle of friction loss
friction loss is directly proportional to the length of hose or pipe….. if 50’ of pipe has FL of 3, then 100’ has a FL of 6
second principle of friction loss
hoses or pipes of the same size, friction loss varies approximately with the square of the increase velocity of the flow…. when flow increases, FL increases ², if FL increases to 4, then FL is 16….as flow increases friction loss increases logarithmically
third principle of friction loss
given the same discharge volume. friction loss varies inversely as the fifth power of the diameter of the hose…. as your hose size increases you have a logarithmic reduction in FL
fourth principle of friction loss
for given velocity, friction losses approximately the same, regardless of the pressure of water…. Friction loss is approximately the same regardless of the pressure water
what is the Darcy-Weisbach formula used for
NFPA 11 Standard for low Expansion Foam, recommends this formula for testing foam proportioning systems
what is the Darcy-Weisbach formula used for
NFPA 11 Standard for low Expansion Foam, recommends this formula for testing foam proportioning systems
