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Fluid Mechanics Lab: Positive Displacement Pumps. ENTC - 303. Objectives. To gain an understanding of the types of positive displacement pumps, their working principle, design and construction. 2. To determine the performance characteristics curves of a positive displacement vane pump. - PowerPoint PPT Presentation
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ENTC-303 PROF. ALVARADO 1
Fluid Mechanics Lab:Positive Displacement Pumps
ENTC - 303
Objectives
1. To gain an understanding of the types of positive displacement pumps, their working principle, design and construction.
2. To determine the performance characteristics curves of a positive displacement vane pump.
ENTC-370 PROF. ALVARADO 2
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Pumps Classification
From www.pumpschool.com
ENTC-370 PROF. ALVARADO 4
Positive Displacement Pumps• Positive displacement pumps have the capability of providing a fairly constant flow rate over a wide range of pressures.•The pump delivers a fixed volume of liquid with every rotation of the input shaft
ENTC-370 PROF. ALVARADO 5
Positive Displacement Pumps
Internal Gear Pump External Gear Pump Vane Pump
Circumferential PumpLobe PumpFlexible member Pump
Figures from www.pumpschool.com
• Positive Displacement for (this week):–High viscosity–Exact flow for different pressures–High pressures
• Centrifugal (next week):–Low viscosity–High flows–Applications requiring a range of flows.
ENTC-370 PROF. ALVARADO 6
Positive Displacement Pumps vs. Centrifugal Pumps
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Positive Displacement Pumpsvs. Centrifugal Pumps
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Positive Displacement Pumps
vs. Centrifugal Pumps
Pump efficiency
• The overall pump efficiency is a product of the volumetric efficiency and the mechanical efficiency
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(P is in Pa; QA and QT are in m3/s; T is in N-m; N is in RPS)
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Pump efficiency
%100T
A
%100___
____
RateFlowVolumelTheoretica
RateFlowVolumeActualEfficiencyVolumetric
Pump efficiency
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Overall Efficiency = Vol.Efficiency x Mech.Efficiency
Actual Power Out = P x QA
Actual Power In = Electrical Power Input (Watts)
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Trial Number
Pressure (Bar)
Pressure (Pa)
Current (Amp)
Time (Sec)
Flow Rate (L/Min)
Flow Rate (m3/s)
1 2 3 4 5
Trial Number
Power Output
(W)Power
Input (W)Overall
Efficiency
1 2 3 4 5
ENTC-370 PROF. ALVARADO 13
Trial Number
Flow Rate (GPM)
Suction Pressure (psig)
Discharge Pressure (psig)
Pressure Difference (psig)
1
2
3
4
5
6
ENTC-370 PROF. ALVARADO 14
References
• www.pumpschool.com• Fluid Power with applications, Anthony
Esposito.
