Equipment

Booster

A Booster represents a pump or compressor that adds energy to the fluid, increasing its pressure or head. It is characterized by its performance curve (head versus flow) and efficiency parameters. Boosters are typically used to overcome elevation or frictional losses in the system.

FlowDesigner includes a comprehensive database of the following boosters:

1. Centrifugal Pumps

2. Rotating Positive Displacement Pumps

3. Fans & Compressors

4. Positive Displacement Pumps & Compressors

Users can add new pump models to this database, a task that you only need to complete once. The new booster will then be stored in the database and will be available for all future modelling projects. The icons in FlowDesigner are tabulated below:

Table 2.5. Types of Boosters available in FlowDesigner.

Booster Type	FlowDesigner Icon	Booster Type	FlowDesigner Icon
Centrifugal Pumps		Positive Displacement Pumps

Calculation Method

Centrifugal Pump Calculation Method

The performance curves for centrifugal pumps are typically expressed as simple polynomials, a series of cubic splines, or, in some cases, as Chebyshev polynomials. FlowDesigner uses these methods to store pump performance data. For a simple polynomial, the head is expressed as:

H = C₁ + C₂Q + C₃Q² + C₄Q³ + …

The pump performance data is adjusted in situ based on the following factors:

Change in operating speed or impeller size

If the pump operates at a speed or with an impeller diameter different from the database values, the performance is adjusted using the affinity laws:

Q₁ / Q₂ = (N₁ / N₂) (D₁ / D₂)

H₁ / H₂ = (N₁ / N₂)² (D₁ / D₂)²

NPSHr₁ / NPSHr₂ = (N₁ / N₂)² (D₁ / D₂)²

P_h1 / P_h2 = (N₁ / N₂)³ (D₁ / D₂)³

Pump Affinity Law equations

Where:

• Q = volumetric flow rate

• N = pump speed (RPM)

• D = impeller diameter

• H = pump head

• P_h = shaft power

• NPSHr = net positive suction head requirement

Viscosity correction

If the pumped liquid has a viscosity higher than 4.3 cSt, FlowDesigner applies a correction to the performance data according to the Hydraulic Institute Standards. This correction is applied only if enabled in the Global Settings Tab of the Calculation Options dialog.

FlowDesigner displays the Pump Shaft Power in the calculated results. The shaft power is calculated from the hydraulic power and the pump efficiency at the duty point using the following formula:

P_h = Q ρ g H / Eff

Where:

• P_h = Pump Shaft Power

• Q = Volumetric flow rate

• ρ = Fluid density

• g = Acceleration due to gravity

• H = Pump head

• Eff = Pump efficiency

2.4.2 Positive Displacement Pump Calculation Method

The volumetric flow delivered by a rotary positive displacement pump is calculated using the expression:

Q = S⋅D⋅R Slip ΔP

Where:

• Q = Volumetric flow rate

• S = Pump displacement per revolution

• D = Pump speed (RPM)

• R = Number of revolutions

• Slip = Volumetric slip coefficient

• ΔP = Pressure difference across the pump