Pump Specific Speed

Introduction

Pump specific speed when running, calculates increases in unit of volume in a unit of time through a unit of head pressure. The characteristics of the suction side of the impeller determine the efficiency. : N_s = \frac{N \sqrt{Q_{bep}}}{H_1^{3/4}}

N_s = \frac{N \sqrt{Q_{bep}}}{H_1^{3/4}}

Where:
𝑁𝑠 βˆ’ Pump Specific Speed
𝐻1 βˆ’ Head per Stage (ft)
𝑄𝑏𝑒𝑝 βˆ’ Capacity at Best Efficiency Point (gpm)
𝑁 βˆ’ Pump Rotational Speed (rpm)

Case Guide

Part 1: Create Case

  1. Select the Pump Specific Speed application from the Pump Module
  2. To create a new case, click the β€œAdd Case” button
  3. Enter Case Name, Location, Date and any necessary notes.
  4. Fill out all required Parameters.
  5. Make sure the values you are inputting are in the correct units.
  6. Click the CALCULATE button to overview results.

Input Parameters

  • Pump Speed (rpm)
  • Capacity at the Best Efficiency Point (gpm)
  • Total Head per Stage at the Best Efficiency Point (ft)

Part 2: Outputs/Reports

  1. If you need to modify an input parameter, click the CALCULATE button after the change.
  2. To SAVE, fill out all required case details then click the SAVE button.
  3. To rename an existing file, click the SAVE As button. Provide all case info then click SAVE.
  4. To generate a REPORT, click the REPORT button.
  5. The user may export the Case/Report by clicking the Export to Excel icon.
  6. To delete a case, click the DELETE icon near the top of the widget.

Results

  • Pump Specific Speed

References

  • ASME B31.4 – 1998 Edition β€œPipeline Transportation Systems for Liquid Hydrocarbons and other Liquids”, Art. 404.1
  • API 1117 – Movement of In-Service Pipelines
  • API 5L, API 5LS and API 5LX – Specification of Pipe Grade
  • ASTM – Various – Weld Joint Factor
  • CFR Code Part 192
  • MMS Regulations
  • USDA-SCS Modified (Permissible Velocity of Water and Soil Erodibility)
  • Pipeline Rules of Thumb Handbook

Updated on December 26, 2023

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