Balance Drum Leak-off Simulation

At PSS Group, we continuously push the boundaries of engineering with advanced CFD software, integrating state-of-the-art turbulence prediction to deliver accurate and actionable insights. Our CFD study showcases the effect of varying the balance drum diameter clearance on a boiler feed pump. We will then predict the pressure distribution, leakage volumetric flow, and total pump head drop (THD) in a boiler feed pump system. The following are some key insights based on the results:

Observations:

1. Balance Drum Clearance Impact:
   • As the clearance increases (from 0.1 mm to 0.8 mm), the leakage flow rate through the balance drum increases significantly, reaching 22.75 m³/h at 0.8 mm clearance compared to only 2.23 m³/h at 0.1 mm clearance.
   • Higher leakage reduces the pump’s operational efficiency, as more fluid bypasses the main flow path.
2. Pressure Variation at Drum Chamber (P2):
   • The pressure at P2 increases as the balance drum clearance grows. At 0.8 mm clearance, the pressure rises to 19.29 bar, whereas it is just 2.50 bar at 0.1 mm clearance.
   • This increased pressure indicates higher hydraulic forces acting on the balance drum, potentially increasing axial thrust.
3. Total Head Drop (THD):
   • The THD slightly decreases with increasing clearance. This could affect the pump’s ability to maintain its designed discharge pressure.
4. Design Balance Quantity:
   • The design balance leakage is noted as 10 m³/h, which corresponds approximately to a balance drum clearance between 0.2 mm and 0.3 mm. Beyond this range, leakage exceeds the design threshold.

Engineering Considerations:

• Optimal Clearance: Based on these results, maintaining a balance drum clearance of around 0.2–0.3 mm would achieve leakage rates close to the design value, minimizing energy losses while ensuring stable pressure distribution.
• Excessive Wear: Larger clearances, such as 0.8 mm, could indicate significant wear or improper machining, leading to substantial operational inefficiencies.
• Axial Thrust: The pressure difference across the drum must be monitored to prevent excessive axial thrust, which could overburden the thrust bearings.

Why Choose PSS Group?

With our CFD expertise, we help customers achieve precision in rotating equipment design, troubleshooting, and performance improvement.

? Contact us today to learn how we can improve your pump efficiency and reliability with our advanced engineering solutions.