Chapter 3: Water in motion: Hydrokinetics Flashcards
Hydrokinetics is:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The study of the characteristics and physical properties of water in motion
What 2 types of energy must be considered when studying hydraulics?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Potential and Kinetic
Energy in a water system cannot be:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Lost or destroyed; It simply changes form back and forth between kinetic and potential energy
The total energy at any point in the system is equal to:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The sum of the potential energy and the kinetic energy at that point
The Principle of conservation of energy states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The total energy within a system will remain constant
Bernoulli’s Theorem:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
In a steady flow without friction, the sum of the velocity head, head pressure, and elevation head is constant for any incompressible fluid particle throughout its course. Another way to say it is the total pressure is the same at any point within the system
The principle of conservation of matter state:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Matter can neither be created or destroyed
Who is the college hydraulics professor that keeps being referenced in this book?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Pat D. Brock
Principle 1 of water flow in piping or hose systems states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
If the pipe or hose size remains constant, water velocity within a system will be constant
Principle 2 of water flow in piping or hose systems states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Within the same system,an increase in pipe or hose diameter will result in a reduction of water velocity
Principle 3 of water flow in piping or hose systems states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Within the same system, a reduction in pipe or hose size will result in an increase of water velocity
Principle 4 of water flow in piping or hose systems states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
If pipe or hose size within a system remains constant, water flowing uphill will travel at the same velocity as water flowing downhill
In this book, pressure is defined as:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Force per unit area
Force is a simple measure of:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Weight and is usually expressed in pounds
To understand how force is determined, you must know:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The weight of water and the height that a column of water occupies
How many feet of water column exerts a pressure of 1 psi at its base?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
2.31 Feet of water
Atmospheric pressure is greatest at:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Low altitudes
Atmospheric pressure is lowest at:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Higher altitudes
The measurement most commonly associated with atmospheric pressure is ______ psi?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
14.7 psi
Standard atmospheric pressure is:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
14.7 psi (Sea level)
A common method of measuring atmospheric pressure is to compare the weight of the atmosphere to the weight of a column of:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Mercury
The greater the atmospheric pressure, the _________ the column of mercury:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Taller
A pressure of 1 psi makes a column of mercury about ______ inches tall:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
2.04
Above sea level, atmospheric pressure decreases approximately _______ psi for every _______ feet?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
0.5 psi for every 1,000 feet
Above 2,000 feet in elevation, the lower atmospheric pressure can be of concern, particularly when:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Operating from a draft
Lower atmospheric pressure reduces a pump’s:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Effective lift while drafting
Most pressure gauges show the pressure in addition to:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The existing atmospheric pressure
Any pressure less than atmospheric pressure is considered a:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Vacuum
Absolute zero pressure is called a:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Perfect vacuum
In fire protection terms, head refers to:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Then height of a water supply above the discharge orifice
Head in feet may be converted to head pressure by:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Dividing the number of feet by 2.31
The water-flow definition of static pressure is:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The stored potential energy available to force water through pipe, fittings, hose, and adapters
The pressure in a water system before water flows from a hydrant is considered:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Static pressure
Normal operating pressure is:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The pressure found in a water distribution system during normal consumption demands
The difference between a system’s static pressure and normal operating pressure results from:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The friction caused by water flowing through the various pipes, valves, and fittings in the system
Residual pressure is:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The part of the total pressure not used to overcome friction loss or gravity while forcing water through pipe, fittings, hose, and adapters
In a water distribution system, residual pressure varies according to:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The amount of water flowing from one of more hydrants, water consumption demands, and the size of the pipe
Flow pressure (Velocity pressure) is: [Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
That forward velocity pressure created at a discharge opening while water is flowing
What device is used to measure flow pressure?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
A pitot tube and gauge
Friction loss can be defined as:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
That part of the total pressure lost while forcing water through pipe, fittings, hose, and adapters
The friction loss in old hose can be as much as ____ percent greater than that in new hose?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
50 percent
1st principle of friction loss states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The amount of friction loss is directly proportional to the length of the hose or pipe
2nd principle of friction loss states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
When hoses or pipes are the same size, friction loss varies approximately with the square of the increase in the velocity of the flow
3rd principle of friction loss states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Given the same discharge volume, friction loss varies inversely as the 5th power of the diameter of hose
4th principle of friction loss states:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
For a given flow velocity, friction loss is approximately the same, regardless of the pressure on the water
What determines the velocity at which a given volume of water will be discharged?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The size of the hose or pipe
Flow pressure will always be the greatest near:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The supply source
Flow pressure will always be the lowest at the:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Farthest point in the system
What are the names of the 2 classic engineering friction loss formulas?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Darcy-Weisbach formula
Hazen-Williams formula
Which of the 2 friction loss formulas is more accurate?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Darcy-Weisbach formula
Which of the 2 friction loss formulas is more widely used by the engineering profession in general?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Darcy-Weisbach formula
Which of the 2 friction loss formulas is recommended for testing foam proportioning systems according to NFPA 11, Standard for Low Expansion Foam?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Darcy-Weisbach formula
Most fire protection circles recognize a Reynolds number of _______ as the transition point from laminar flow to turbulent flow:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
2,100
Seldom, if ever, will you encounter a true _________ flow in a fire protection setting:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Laminar
The fire protection industry uses which of the 2 formulas more commonly than the other?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Hazen-Williams formula
NFPA 13, Standard for installation of sprinkler systems, requires the use of which of the 2 formulas for hydraulic friction calculations?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Hazen-Williams formula
NFPA 24, Standard for the Installation of Private Fire Service Mains and their Appurtenances recommends using this formula of the 2:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Hazen-Williams formula
This formula allows us to calculate the water velocity given a specific head loss:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The Hazen-Williams formula
Fire protection professionals are more interested in determining the friction loss in a pipe when they know:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
The pipe’s size and roughness
The flow rate in gallons per minute
What is the single variable with the greatest impact on friction loss?
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Pipe Diameter
The actual internal diameter of any given pipe will differ slightly from the:
[Fire Service Hydraulics and Water Supply: Chapter 3: Water in motion: Hydrokinetics]
Nominal size of the pipe
