Ansi Hi 9.8 Rotodynamic Pumps For Pump Intake Design
HI 9.8 allows CFD if it solves the Unsteady Reynolds-Averaged Navier-Stokes equations (URANS) or Large Eddy Simulation (LES). The mesh must be fine enough to resolve the bell gap (C).
Pros: Cheap, fast, iterative. Cons: May miss free-surface vortices if not using VOF (Volume of Fluid) methods.
The standard (9.8-2018, the latest revision) applies specifically to rotodynamic pumps operating in wet well or open sump configurations. It focuses on:
It does not cover positive displacement pumps or closed-loop systems with pressurized suction headers (though those principles often cross-apply).
✅ Intake flow velocity < 0.5 m/s
✅ Submergence ≥ 1.5D (verify with HI 9.8 curve)
✅ Bottom clearance 0.3D – 0.5D
✅ No free-surface vortices visible during operation
✅ Straight approach length ≥ 5× bay width
✅ CFD or physical model for complex geometries
Pro Tip: Even if your pump meets HI 9.8 intake design, re-check after any change in flow rate, water level, or basin modification. Hydraulic conditions can shift vortex formation thresholds. ansi hi 9.8 rotodynamic pumps for pump intake design
Would you like a one-page printable checklist derived from this content, or a CFD modeling guideline supplement for HI 9.8 compliance?
ANSI/HI 9.8: A Comprehensive Guide to Rotodynamic Pumps for Pump Intake Design
The American National Standards Institute (ANSI) and the Hydraulic Institute (HI) have collaborated to develop a comprehensive standard for the design of pump intakes for rotodynamic pumps, known as ANSI/HI 9.8. This standard provides guidelines and best practices for designing pump intakes that ensure efficient and reliable operation of rotodynamic pumps. In this write-up, we will explore the key aspects of ANSI/HI 9.8 and its significance in pump intake design.
What are Rotodynamic Pumps?
Rotodynamic pumps, also known as centrifugal pumps, are a type of pump that uses a rotating impeller to increase the velocity of a fluid, which is then converted into pressure energy. These pumps are widely used in various industries, including water supply, wastewater treatment, chemical processing, and power generation. It does not cover positive displacement pumps or
Importance of Pump Intake Design
The pump intake is a critical component of a rotodynamic pump system, as it directly affects the pump's performance, efficiency, and reliability. A well-designed pump intake ensures that the pump receives a steady and uniform flow of fluid, which is essential for optimal pump operation. A poorly designed pump intake, on the other hand, can lead to issues such as:
ANSI/HI 9.8: A Comprehensive Standard for Pump Intake Design
ANSI/HI 9.8 provides a comprehensive framework for designing pump intakes for rotodynamic pumps. The standard covers various aspects of pump intake design, including:
Key Benefits of ANSI/HI 9.8
The ANSI/HI 9.8 standard offers several benefits to pump users, designers, and manufacturers, including:
Best Practices for Pump Intake Design
Based on ANSI/HI 9.8, the following best practices are recommended for pump intake design:
Conclusion
ANSI/HI 9.8 provides a comprehensive framework for designing pump intakes for rotodynamic pumps. By following the guidelines and best practices outlined in this standard, pump users, designers, and manufacturers can ensure that pump intakes are designed to optimize pump performance, efficiency, and reliability. As the demand for efficient and reliable pump systems continues to grow, the importance of ANSI/HI 9.8 will only continue to increase. By adopting these best practices and guidelines, industries can reduce energy consumption, extend pump lifespan, and improve overall pump system performance. ✅ Intake flow velocity < 0
This is the distance from the water surface to the top of the bell inlet.
Poor intake design is a leading cause of pump vibration, cavitation, efficiency loss, and premature bearing/seal failure. ANSI/HI 9.8 (Hydraulic Institute Standard for Rotodynamic Pumps – Intake Design) provides the industry’s definitive guidelines to avoid these issues. It applies to centrifugal, mixed-flow, and axial-flow pumps in wet-pit, suction-bell, and can-pump configurations.