test specimen

• pump sumps
• intakes and outfalls

applications

• industrial, power and desalination plants
  • drinking water supply
  • sewage systems
  • irrigation and drainage
• proper pump operation
• minimum dimensions
• design evaluation and optimization
• design verification and witness testing

features

• test fluid: water
• model basin: size 22 m x 11 m
• model scale factor: 1:4 to 1:12
• multiple pumps (up to 20)

test procedures

Testing takes place according to international standards (ANSI/HI 9.8-1998). All parts of the pump sump which are relevant to the flow conditions at the pumps are reproduced on scale. The pump bellmouths and suction pipes are modelled in detail. Pump operation is simulated by syphoning. The flow is supplied by a pump with variable speed.

Model testing includes the following steps:

• original design
  determination of worst operating conditions, based on swirl and vortex observations
• modified design
  application and testing of splitters, corner fillings, etc. (in consultation with client), to optimize flow patterns, dimensions and construction cost
• final design
  verification by detailed measurements (swirl, velocity profiles in suction pipes, etc.) and witness testing. Screen clogging, air entrainment and exaggerated velocity tests

measuring equipment

• EMF flow meters
• micro-propeller meters (local velocity)
• rotometers (swirl)
• dye injection (flow visualization)
• photographs, video

acceptance criteria

• temporal and spatial velocity distributions in the suction pipes should not deviate more than 10% from the mean values
• pre-rotation: swirl angle in suction pipes should be less than 2.5 - 5 degrees (depends on pump type)
• free surface and submerged vortices with core formation are not allowed
• other specific criteria (e.g. from pump manufacturer)

more information

For more information contact Paul-Henri Leruth.