TURBOMACHINERY - FLUID ENGINEERING
PUMPS ARE GENERALLY MACHINES THAT
MOVE FLUID, SPECIFICALLY LIQUIDS, FROM
ONE POINT TO ANOTHER.
MAIN FUNCTIONS ARE:
• TRANSFER A LIQUID VOLUME FROM A
LOWER SOURCE TO A HIGHER LOCATION.
• MAINTAIN PRESSURE WITHIN A CLOSED
SYSTEM SUCH AS FIRE PROTECTION
SPRINKLERS, HYDRANTS, OR POTABLE
WATER SYSTEMS.
DYNAMICS/KINETIC PUMPS
• IMPART VELOCITY AND PRESSURE TO
FLUIDS UPON PASSING TO IMPELLERS
• CENTRIFUGAL AND VERTICAL TURBINE
• HIGH SPEED OPERATIONS
• IDEAL FOR LESS VISCOUS LIQUIDS SUCH
AS WATER
POSITIVE DISPLACEMENT PUMPS
• COMPRESSES
LIQUID
UPON
PASSING
THROUGH THE PPUMPING ELEMENT
• ROTARY AND RECIPROCATING PUMPS
• LOW SPEED OPERATIONS
• IDEAL FOR VISCOUS LIQUIDS SUCH AS
SLUDGE OR FUELS
Volume Flowrate
(Capacity)
Q̇
lps or gpm
Specific Weight
γ
kN/m3 or lbf/ft2
Total Dynamic Head
(Net Head)
H
m or ft
The difference between the suction and discharge pressure that is to be
overcome by a pump. It is best expressed in meters of liquid column. It is
calculated using the Bernoulli’s Equation which is composed of 4
parameters:
• Pressure Head
• Kinetic (Velocity Head)
• Static (Elevation Head)
• head loss due to friction
𝑷𝟐 − 𝑷𝟏 𝒗𝟐𝟐 − 𝒗𝟐𝟏
𝑻𝑫𝑯 =
+
+ 𝒛𝟐 − 𝒛𝟏 + 𝒉𝒇
𝜸
𝟐𝒈
Determining the suction and discharge pipe sizes.
Pipe size can be calculated using the Continuity
Equation with the internal velocity of the fluid
being the controlling parameter.
ሶ
𝟒𝑸
𝒗𝒊 =
𝝅𝒅𝟐𝒊
Recommended internal velocity for suction and
discharge pipes are 0.60 ~ 1.50 and 1.50 ~ 2.50
m/s respectively.
Pipes can be metallic or plastics depending on
the handled medium and pressure
requirements.
Determine what is the type of flow inside the pipe. The type of flow is
determined by the Reynold’s Number, Re.
• Laminar Flow; Re ≤ 2,300
• Transitional Flow; 2300 ≤ Re ≤ 4000
• Turbulent Flow; Re ≥ 4000
𝒗𝒊 𝒅𝒊 ρ
𝐑𝐞 =
𝝁
Depending on the type of flow, the friction factor, f, is to be calculated
using either the Moody Diagram or the following formulas
Turbulent Flow,
Laminar Flow
𝟔𝟒
𝒇=
𝑹𝒆
Colebrook-White
𝟏
𝛆/𝒅𝒊
𝟐. 𝟓𝟏
= −𝟐. 𝟎 𝒍𝒐𝒈
+
𝟑. 𝟕 𝐑𝐞 𝒇
𝒇
As the fluid moves within the pipes, friction occurs causing losses in the
head which is to be accounted in pump sizing.
Head Loss in Pipes
Head Loss in Pipes,
Darcy-Weisbach
Hazen-Williams
𝒉𝒍 =
𝐟𝐥𝒗𝟐
𝟐𝐠𝒅𝒊
𝟏.𝟖𝟓
ሶ
𝑸
𝒉𝒍 = 𝟏𝟎, 𝟕𝟎𝟎
× 𝑫−𝟒.𝟖𝟕
𝑪
As the fluid moves within the pipes, friction occurs causing losses in the
head which is to be accounted in pump sizing.
Head Loss in Fittings and Valves,
Head Loss in Fittings and Valves,
Loss Coefficient
Equivalent Length
𝒗𝟐𝒊
𝒉𝒍 = 𝒌
𝟐
𝑳
𝑳𝒆 = 𝑫
𝑫
Mechanical power (hydraulic) is the power input or added into the fluid
with consideration of the pump’s hydraulic efficiency, Phyd.
• kW (Metric) or hp (English)
• ηm = 0.60 ~ 0.80
ሶ
𝑸𝜸𝑯
𝑷𝒉𝒚𝒅 =
𝜼𝒎
Electrical Power (Motor/Brake Horsepower) is the external power
supplied to the pump considering the electrical motor efficiency, Pele.
• ηe = 0.80 ~ 0.90 (theory)
• ηe is already standardized either by NEMA or IEC standards.
𝑷𝒉𝒚𝒅
𝑷𝒆𝒍𝒆 =
𝜼𝒆