Net positive suction head available (NPSHa) and required (NPSHr) are important parameters to ensure adequate supply conditions are provided to the pump. AFT Fathom accepts NPSHr curves and reports a calculated NPSHa based on the modeled system. NPSHr curves are typically supplied by pump vendors.
NPSHr information can be found in the 11th edition of API 60. NPSHr curves can also vary with varying speed. AFT Fathom allows users to specify an affinity exponent to modify the NPSHr curve at different speeds.
Resources
Blog –
Case study – Nuclear Power Station Service Water Pump NPSH Hydraulic Model Using AFT Fathom
Standard – Rotodynamic Pumps Guideline for NPSH Margin (ANSI/HI 9.6.1-2017 – Secure PDF)