Pump Definition Types

There are numerous types of pump definitions in Bentley storm and sanitary sewer models. These are described below. These pump definitions are established by the user using Components > Pump Definitions. The user can assign these definitions to any pump elements. Pump definitions contain the pump curves describing pump performance. The only curves that are mandatory are the pump head curves. Efficiency and motor curves are only used in Bentley water models.

Some of the definitions are used only in the implicit and explicit dynamic wave solvers while others are only used in the pressure portion of the GVF-convex solver. The only definition type that is common to all solvers is the Multipoint pump head curve.

The individual pump definitions are described below. The suffixes (GVF or DW) indicate whether they are used in the GVF-convex solver or implicit or explicit dynamic wave solvers.

Volume vs Flow - DW

This pump definition type is best suited for pumps which have either wet wells or ponds as the source element. The curve relates the volume of water in the source element to the outflow of the pump station. As the volume increases, the discharge increases.

Depth vs Flow - DW

This pump definition type simply relates the depth of flow of the source element to the outflow of the pump. As the depth increase, the discharge increases incrementally.

Multipoint - DW and GVF

This is the most standard pump definition type. It relates the head difference between the upstream and downstream nodes to the discharge of the pump. As the head difference increases, the amount of discharge decreases.

Depth-Flow (Variable Speed) - DW

This pump definition type also relates the depth of the source node to the discharge of the pump. As the depth increases, the discharge increases continuously.

Constant Power - GVF

When selecting a Constant Power pump, the following attribute must be defined:

• Pump Power-Represents the water horsepower, or horsepower that is actually transferred from the pump to the water. Depending on the pump's efficiency, the actual power consumed (brake horsepower) may vary with flow but is not accounted for in this type of pump definition.

Design Point (One-Point) - GVF

When selecting a Design Point pump, the rated head and flow of the pump are specified and a reasonable head vs. flow relationship is used based on a radial flow centrifugal pump.

Standard (Three-Point) - GVF

When selecting a Standard Three-Point pump, three points on the pump curves must be specified. Tthe following flow vs. head points must be definedare usually used:

• Shutoff - Point at which the pump will have zero discharge. It is typically the maximum head point on a pump curve.
• Design - Point at which the pump was originally intended to operate. It is typically the best efficiency point (BEP) of the pump. At discharges above or below this point, the pump is not operating under optimum conditions.
• Max Operating - Highest discharge for which the pump is actually intended to run. At discharges above this point, the pump may behave unpredictably, or its performance may decline rapidly.

Standard Extended - GVF

When selecting a Standard Extended pump, the following flow vs. head points must be defined:

• Shutoff - Point at which the pump will have zero discharge. It is typically the maximum head point on a pump curve.
• Design - Point at which the pump was originally intended to operate. It is typically the best efficiency point (BEP) of the pump. At discharges above or below this point, the pump is not operating under optimum conditions.
• Max Operating - Highest discharge for which the pump is actually intended to run. At discharges above this point, the pump may behave unpredictably, or its performance may decline rapidly.
• Max Extended - Absolute maximum discharge at which the pump can operate, adding zero head to the system. This value may be computed by the program, or entered as a custom extended point. This value is automatically calculated for Standard Extended pumps.

Custom Extended - GVF

When selecting a Custom Extended pump, the following attributes must be defined:

• Shutoff - Point at which the pump will have zero discharge. It is typically the maximum head point on a pump curve.
• Design - Point at which the pump was originally intended to operate. It is typically the best efficiency point (BEP) of the pump. At discharges above or below this point, the pump is not operating under optimum conditions.
• Max Operating - Highest discharge for which the pump is actually intended to run. At discharges above this point, the pump may behave unpredictably, or its performance may decline rapidly.
• Max Extended - Absolute maximum discharge at which the pump can operate, adding zero head to the system. This value may be computed by the program, or entered as a custom extended point.