Momentum Transfer Flashcards
For the laminar flow of a fluid in a circular pipe of radius R, the Hagen-Poiseuille equation predict the volumetric flowrate to be proportional to
R^4
When the flow is laminar
the pressure drop is proportional to the first power of the velocity.
Pipes having diameter 14 inches or more are designated by
their
outside diameter
Most commonly used joint in the underground pipe lines is the
sleevejoint
Schedule number of a pipe, which is a measure of its wall thickness, is given by
1000 P’/S
Water hammer in a pipeline results from the
rapid pressure change due to a rapid change in the rate of flow.
Molten soap mass is transported by a _____ pump.
Gear Pump
Nominal size of the discharge pipe of a pump is usually______ the nominal size of the inlet pipe.
smaller than
Location of vena-contracta in an orificemeter does not depend
upon the
type of orifice
High specific speed of a pump implies that, it is a/an ____ pump.
axial flow
Fittings used to connect two pipes with different size.
Reducer
CH 10
Fittings used to change direction.
Elbows
CH 10
Fittings used for branching.
Tee
CH 10
Fittings used to connect the same pipe diameter
Union
CH 10
Formula used for Laminar and Compressible Fluids
Poiseuille Equation
Formula for Compressible Fluids
E6-115
Weymouth equation
. 0.008
ƒ = ———-
D^⅓
For Methane only
Compressible fluids
Examples of compressible fluids
Nitrogen
Natural Gas (Ex. Methane)
Compressors, Fans & Blowers
Formula for Adiabatic Compressor
E10-67
TO AVOID USING MOLES,
REPLACE RT TO PV
Compressors, Fans & Blowers
Why is N added in the formula of Adiabatic Compressor?
If Power is too big, N is added.
N is the # of stages of the compressor.
Compressors, Fans & Blowers
What is k or ɣ in the formula of Adiabatic Compressor? What is the value?
ɣ=Cp/Cv
Monoatomic: ɣ=1.67
Diatomic: ɣ=1.4
If CO2, CH4, etc.: ɣ = T2-76
Compressors, Fans & Blowers
Formula in determining the pressure in a particular stage in a multi-stage compressor
Ratio, r = (Pn/Po)^1/N
P1 = Po × r
P2 = P1 × r
P3 = P2 × r
Po = initial pressure from Stage 1
Pn = final pressure from Stage N
Ratio of Darcy Friction factor and Fanning Friction factor
fD
—- = 4
fF
Compressors, Fans & Blowers
Formula of Fans and Blowers
W’ = ∆KE + ∆PE + ∆P/ρ,ave + ΣF
where: ρ,ave = (ρ1 + ρ2) /2
Flowmeters: Pitot Tube
Given: Rm
Required: Qv
Qv =vA
➡️ v,ave?
↘️ v,max = c √2gc∆H (E10-11)
↘️ ∆H = Rm (SGm/SG -1) g/gc
↘️ Re,max
↘️ v/v,max
Pitot Coeff, C = 1 if not given
∆H = ∆P/ρ
Flowmeters: Pitot Tube
Given: Qv
Required: Rm
∆H = Rm (SGm/SG -1) g/gc
➡️ ∆H=? v,max = c √2gc∆H (E10-11)
➡️ v,max?
↘️ v, ave= Qv/A
↘️ Re
↘️ v/v,max
Pitot Coeff, C = 1 if not given
∆H = ∆P/ρ
Flowmeters: Pitot Tube
Given: Qv
Required: Rm
Qv =vA
➡️ V, max = c √2gc∆H
↘️
➡️ Re
➡️ V,ave (T10-10)
Pitot Coeff, C = 1 if not given
∆H = ∆P/ρ
In orifice, there’s a sudden contraction of fluid then it will suddenly expand, resulting in high friction and high losses. This phenomenon is called.
VENA CONTRACTA
Flow Meters
Formula for Orifice and Venturi Meters
v2 = c √(2gc•∆H)/(1-β⁴) ; E10-20
where: β=D2/D1
Qv = v1A1 = v2A2
where: v=F/A of venturi/orifice
C,orifice = 0.61 if Re>30,000
C,venturi = 0.98 if Re>10,000
Letter V>O
D1 = pipe
D2 = venturi or orifice
