Dear All,
I am conducting an analysis of existing lift station and its downstream piping system. What are the things you can suggest that I need to look out first or should I ask, what are the first thing to consider on my model?
I am thinking that there should be some different settings to consider compare to the new piping system.
The piping system are already too old as well as the lift stations. They are ranging from 20-35 years old already.
Thanks & Regards,
June
Did you have any specific questions on the use of SewerCAD? Do you have a specific goal or problem you need to solve by using the model?
For an older system, you will likely need to adjust the friction coefficients of the pipes and pump definitions accordingly.
For general modeling advice, I would recommend our Wastewater Collection System Modeling and Design book:
pages.info.bentley.com/books
Here are some chapters in particular that may be helpful:
Chapter 11 - Wastewater Collection System Evaluation and Rehabilitation
Chapter 12 - Force Mains and Pump Stations
Regards,
Jesse DringoliTechnical Support Manager, OpenFlowsBentley Communities Site AdministratorBentley Systems, Inc.
Jesse,
On friction coefficients, do all of the coefficients default on Sewer Cad are ideal for every material when they are new? How much I am going to lower them to satisfy an old piping system?
For pumps, they are already old, like what I have said they are already 20-35 years old already. What are the things you can suggest to be adjusted on pump settings, since it is old already? (Pls. note that the lift stations don't have any metering device)
The friction coefficients provided in the default engineering library are typically for new pipes.
Not every pipe ages the same way, and there may be other factors that influence the effective roughness of an old pipe, like roots, cracks, etc. You may need to inspect some of the pipes. Table 4.2 in the "WCSMD" book mentioned in my last post has some suggested Hazen Williams roughness values for certain types of pipe of different age. Chapter 11.3 talks about hydraulic investigation.
For pumps, you would adjust the pump characteristic curve (head and flow) to compensate for the reduction in performance due to age. Similar to pipe roughness, the exact extent that you adjust this could be effected by multiple factors. You may need to do a performance test. See Chapter 4.3 in the "WCSMD" book for more on pump performance.
Ideally if you have enough data, you would calibrate the model by adjusting things like the roughness coefficients until the model results match field measurements. Chapter 9 in the "WCSMD" book talks about model calibration.
Without a metering device, you may need to make a conservative assumption on these adjustments. Again, a bit more information on exactly what problem you need the model to solve would be helpful.
Answer Verified By: june_0809@yahoo.com
Actually, I got the answer that I need.
Thank you very much!
Best Regards,