This example compares the power consumed by pumps that take three different control signals. Each pump has identical mass flow rate and pressure rise.
Note that for the instances
Annex60.Fluid.Movers.FlowControlled_dp
and
Annex60.Fluid.Movers.FlowControlled_m_flow,
we had to assign the efficiencies (otherwise the default constant
efficiency of 0.7 would have been used).
In these models, the power consumption is computed
using similarity laws, but using the mass flow rate as opposed
to the speed, because speed is not known in these two models.
This is an approximation at operating points in which
the speed is different from the nominal speed N_nominal
because similarity laws are valid for speed and not for
mass flow rate.
The figure below shows the approximation error for the power calculation where the speed Nrpm differs from the nominal speed Nnominal.
Name | Description |
---|---|
Medium | Medium model |
pump_dp
and pump_m_flow
, because
using a parameter
and assigning this parameter
leads
in OpenModelica to the error message
expected subtype of record Annex60.Fluid.Movers.Data.Generic
.