Hi,
I tried to model the steady state condition for one hydropower plant with francis turbine. I was able to get the net head at turbine, however the friction factor at pipe before headrace is zero. I already input the darcy roughness height for the specific pipe section. Need your help on this.
Also, i would like to model a surge tank (5m dia. and 9m height) along the penstock. The intended design was to connect the surge tank with a pipe of 30m length (2m dia.) to surge tank and the surge tank elevated to reservoir level. The surge tank is about 22m height difference from the tee off pipe to surge tank base elevation. The penstock is 2m dia.
Reservoir level: 2436 masl
Surge tank base elevation: 2436 masl
Tee off pipe centreline: 2402.27 masl
I got an error mesage when trying to set up the surge tank, "Initial level in the surge tank is higher than the top or below the pipe elevation. The initial liquid surface must be between the top of the tank and the pipe elevation.". Could you advise on this?
I attached the model for your reference.
Hello,
This appears to be because the the surge tank is treated as a junction in the initial conditions, but the hydraulic grade results are lower than the tank operating range. If you look at the hydraulic grade results at the surge tank for the initial conditions calculation, it is 2,433.54 meters, which is below the bottom of the tank. This is impacting the transient results.
If you set the surge tank property "Treat as Junction?" to False and compute the model, the hydraulic grade at the surge tank will now be at the initial elevation value and the transient simulation will compute.
Regards,
Scott