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61 Cards in this Set

  • Front
  • Back
Who will pass the PE
Me!
What is the best Engineering forum on the planet
Engineerboards.com
Energy of a mass
the capacity of a mass to do work
Joule's Constant
778 ft-lbf/Btu
work (def)
the act of changing the energy of a particle, body, system
potential energy (def and eq)
a form of mechanical energy possessed by a body due to it's position in a gravitational field

E=m*g*h/gc

E is per unit mass in the fluids chapters and not in the thermo chapters
kinetic energy (def and eq)
a form of mechanical energy associated with a moving or rotating body

E=m*v^2/(2*gc)

E is per unit mass in the fluids chapters and not in the Thermo chapters
Convert from rpm to rad/sec (eq)
rpm*2*pi/60
or
rpm *0.1047
Ideal fluids (def)
has no viscosity, & is incompressible
absolute pressure (def)
measured with respect to a true 0 pressure reference
gage pressure (def)
measured with respect to atmospheric pressure
Standard atmospheric pressure (numerical value)
1 atm
14.7 psia
Density (def)
a fluid's mass per unit volume
Specific gravity (def)
a dimensionless ratio of a fluid's density to some standard reference density
Specific wieght (def)
the weight of a fluid per unit volume
absolute viscosity (def)
μ

a measure of that fluid's resistance to flow when acted upon by an external source
kinematic viscosity (def)


the ratio of absolute viscosity to mass density
hydrostatic pressure (def)
pressure a fluid excerts on an immersed object or container walls
The relationship between pressure and depth (eq)
p=ρ*g*h/gc
gravitational constant (numerical value)
32.2 lbm-ft/(lbf-sec^2)
laminar flow (numerical value)
re below 2100
Reynolds number (eq)
Re=D*V*ρ/(gc*μ)
Re=D*v/∨
Re=D*G/gc*μ

G=mass flow rate per unit area
Turbulent flow (numerical value)
re greater than 4000
mass flow rate (eq)
ρ*A*v
laminar flow eq for friction factor (eq)
f=64/Re
darcy equation (eq)
hf=(f*L*v^2)/(2*D*g)
Specific energy (def and units)
energy per unit mass ft-lbf/lbm

E is per unit mass in the fluids chapters and not in the thermo chapters
Ef (specific frictional energy) (eq)
Ef=(f*L*v^2)/(2*D*gc)

E is per unit mass in fluids chapters and not in the thermo chapters
head loss due to pressure drop (eq)
deltap=hf*ρ*(g/gc)
Fluid velocity in terms of mass flow rate, density, and area (eq)
v=mdot/(ρ*A)
terminal velocity (def)
the velocity of an object falling through a fluid will continue to increase untill the drag force equals the net downward force
frictional head (eq)
hf=(f*L*v^2)/(2*D*g)
velocity head (eq)
hv=(v^2/2*g)
static suction head hz(s) (def)
the vertical distance above the centerline of the pump inlet to the free level of the fluid surface. If the free level of the fluid is below the pump inlet, hz, will be negative and is known as static suction lift
static discharge head hz(d) (def)
The vertical distance above the centerline of the pump inlet to the point of free discharge or surface level
weight (eq)
W=m*g/gc
acceleration of gravity (numerical value)
32.0 ft/sec^2
9.8 meter/sec^2
Area and circumference of a circle (eq)
A=π* r^2
C=2*π*r
volume and surface area of a shere (eq)
V=4*π*r^3/3
A=4*π*r^2
Right triangle equations (eq)
Some Old Hags Can't Hide There Old Age
sin= opposite side/ hyp
cos= adj side/ hyp
tan= opposite side/ adj side

a^2 + b^2 = c^2
Power (eq and def)
is the amount of work per unit time

P=W/Δt
P=F*v (linear systems)
P=T*ω (rotational systems)
what the eq that relates lbm to slugs (eq)
Lbm=slugs*g (g in ft per sec2)
density of water at STD (numerical value)
62.4 lbm/ft^3
1 HP equals? (eq to change units)
hp=550 ft-lbf/s
How are mass and volume related (eq)
m=ρ*V
What is a subcooled liquid (def)
If a liquid is not saturated (not at it's boiling point) it is said to be subcooled. Water at room temp is subcooled since adding a small amount of heat will not cause vaporization
what is a saturated liquid (def)
a liquid that has absorbed as much heat energy as it can without vaporizing. Liquid water at 212F is an example
liquid vapor mixture (def)
a liquid and vapor can coexist at the same temp and pressure.
saturated vapor (def)
a vapor on the verge of condensing. steam at 212F and STD pressure
superheated vapor (def)
is a vapor that has absorbed more heat than is needed merely to vaporize it. A superheated vapor will not condense when a small amount of heat is removed
ideal gas (4 eq)
p*V=Rstar*T
p*V=n*R*T
ρ=p/(R*T)
mdot=p*Vdot/(R*T)

note R is gas specific and Rstar is not.
What is a gas (def)
a highly superheated vapor
specific volume in terms of density, and what are the units for specific volume (eq)
ν=1/ρ

ft3/lbm
enthalpy (def)
is the total useful energy of a substance (internal energy, u, and flow energy, p*V. Define as useful energy because all of it can be used to preform useful tasks.
entropy (def)
a measure of the energy that is no longer available to proform useful work within the current environment
The specific gas constant, R, for air is
53.35 ft-lbf/(lbm-degreeR)
Eq for Mass flow rate
mdot=ρ*v*A
What is the Energy Efficiency Ratio? (eq)
EER=3.41*COP
What is the Sefan Boltzman Constant (numerical value)
5.67*10^(-8) Btu/hr*ft^2-R^4
Sensible Heat (def)
pure thermal energy that increases the air's dry bulb temp
Latent heat (def)
moisture that increases the air's humidity ratio