Science unit 1 (Hydronics and pneumatics) Flashcards
What is Hydraulics?
What are the to categories it can be split into and what are they?
Hydraulics: The study of Liquids
Hydrodynamics: is the study of liquids in motion
Hydrostatics: is the study of liquids in a stationary state
What is Pneumatics?
Pneumatics: Is the study of Gas
What is a defining Characteristic of Liquids?
Liquid: Definite volume but not definite shape (it takes the shape of its container)
What is a defining Characteristic of Gas?
Gas: Has no definite shape or volume
How are liquids and gasses similar?
Liquids and gases are similar in that they are both made up of matter and can both be made to flow through a pipe
Define Matter
Matter: anything that has both mass and volume
Define Mass
Mass: The amount of matter in a body (Measured in grams)
Define Weight
Weight: is a measure of the force of gravity acting on a mass (Measured in Newtons or Pounds)
Define Volume:
Volume: The amount of space occupied by a body (Measured in cubic units ft cubed or cm cubed)
Define Capacity
Capacity: The amount of space within a container (measured in Liters or Gallons)
Define Density
Density: The amount of matter in a body divided by the volume
Define Specific Gravity (relative density):
Specific Gravity (relative density): is the density of a material compared (divided by) to the density of a standard comparison material (ex: Liquids or solids to water, and Gasses to Air)
Define Specific Volume
Specific Volume: is the amount of volume occupied by a unit mass of a material (volume divided by mass)
Define Viscosity and what happens to it when temperatures increase
Viscosity: the measure of thickness of a liquid
- When temperature increases viscosity decreases
Define Adhesion
Adhesion: The bonding of dissimilar materials or substances (Ex glue, or solder)
Define Cohesion
Cohesion: The tendency of some substance to resist contact with another substance.
Define Capillary action
and give an example in the plumbing industry of it
Capillary action: Tendency of the surface of a liquid to rise in a solid narrow tube. Using both adhesion and cohesion. A perfect example of this is soldering, the adhesion pulls the solder further into the pipe gap, well the cohesion pull or solder with that solder.
Adhesion is the more important force in Capillary action
Define Meniscus and what concave vs Convex looks like
Meniscus: is the name of the curved upper surface of a water column
- Concave means the walls of the container are wetted (Adhesive)
- Convex means the walls are not wetted (Cohesive)
Define Immersed
Immersed: fully covered in water
Define Submerged
Submerged: fully covered in water
Define Emersed
Emersed: standing in but is rising out of the water
Define Absorb
Absorb: to soak up into a body
Define Adsorb
Adsorb: to take up and hold on to an outside surface
Define Imbibe
Imbibe: Means to drink deeply
What is Pascals Law
Pascal’s Law: A confined liquid transmits added pressure equally in all directions throughout the liquid, and that this pressure acts at right angles to all surfaces.
What is Boyles law
Boyle’s Law: the volume of a confined gas varies inversely with the absolute pressure if the temperature is held constant in a closed system.
What is Charles Law
Charles Law: the volume of a confined gas is proportional to the absolute temperature of the gas, when the absolute pressure is constant.
Define Area
Area: is the amount of surface space within a geometric shape
Define Force
Force: is push or pull acting on a body
Define Buoyancy
Buoyancy: is the force which tends to lift a body within a fluid
Where is Buoyancy used in plumbing?
Where is Buoyancy used in plumbing?
Float control
Flush tanks
Pill switch
Sump pump on/off switch
Define Pressure
Pressure (P): the magnitude of the application of force to a surface
Define Gauge Pressure
Gauge Pressure (Pg): is the pressure measured by a gauge
Define Atmospheric Pressure
Atmospheric Pressure (Patm): refers to the pressure of air acting down amount a specific location, at sea level Patm is 14.7psi
Define Absolute pressure
Absolute pressure (Pabs): is the sum of both Pg and Patm and are often used with calculations involving gases
What are 3 ways to measure Pressure
3 ways to measure pressure:
Open standpipe, Bourdon tube pressure gauge, Manometer (only for low pressures), and Barometer
Define a Partial vacuum
Partial Vacuum: Represents any pressure less than atmospheric pressure (not a perfect vacuum)
What is a example of a Partial vacuum
Give one example of a partial vacuum.
Syphon
List three places that syphons are used in plumbing?
List three places that syphons are used in plumbing?
Toilets, flush tanks, self-emptying septic tanks
What is Draw Down Volume
Draw Down Volume: Volume of water that can be removed from a pressure tank between pump cut out and pump cut-in pressures
What are the 2 systems Absolute temperatures can be expressed as?
Absolute temperatures:
Kelvin = Degrees C + 273
Rankin = Degrees F + 460
Explain Bernoulli’s Theorem
Explain Bernoulli’s Theorem.
The sum of Pressure Head, Elevation Head and Velocity Head is constant in a free flowing system.
Define Flow Rate.
Define Flow Rate.
Flow rate is the quantity (volume) of water moving per time
Define Velocity:
Define Velocity: Velocity is the linear distance per time of a moving fluid (speed)
What is Laminar vs Turbulent flow?
Laminar: Streamline or straight, faster in the middle slower on the edges
Turbulent: Swirling or chaotic, many changes in speed and direction
List 5 causes of Turbulent flow.
List 5 causes of Turbulent flow.
Rough inside surface of pipe, poor or improperly fitted joints, bend or elbows, valves, Viscosity
What is one downside to turbulent flows?
What is one downside to turbulent flows?
Can result in pipe erosion
In a steady flow situation as pipe size decreases does the velocity increase or decrease?
increase
In a steady flow situation as velocity increases does the psi reading increase or decrease?
decrease
What is pressure head
Pressure Head: is the height of fluid in feet that can be held up in a vertical column
How is Velocity Head measured?
Pitot Tube
What does Cavitation sound like?
Gravel in the system
What is the most common cause of Cavitation?
Reduction of pressure
