7 Replies Latest reply on Jul 16, 2016 8:24 AM by Will Griffiths

    FAN - inlet pressure dependency on volume flow rate

    Teresa Coronado

      Hello everybody,

       

      Is it possible to define the environmental pressure at the inlet of a fan as a function of a goal?

       

      If you use an external inlet fan and you click on “Thermodynamic parameters” - “Dependency”, you just have two options: “Constant” or “Formula definition”, but if you use “Formula definition” you can’t choose a goal as a parameter…

       

      I want to impose the drop pressure at the inlet of the fan as a function of the volume flow rate through that fan.

       

      Thank you in advanced,

       

      Best regards

       

      Teresa

        • Re: FAN - inlet pressure dependency on volume flow rate
          Jared Conway

          i don't think all functions can reference a goal but in your case i think you're going to create a circular reference

           

          could you explain a bit more about what type of affect you're trying to account for?

           

          the definition of a fan today is that it will adjust the flow rate of the fan based on the pressure difference between the inlet and outlet of the fan (based on the system).

            • Re: FAN - inlet pressure dependency on volume flow rate
              Teresa Coronado

              Hi Jared,

               

              I'm going to try to explain what I would like to do.

               

              I have a system as follows: compact HVAC unit à Fan à Duct

               

              I have the geometry of the duct completely define. I have the drop pressure – volume flow rate curve of the fan.

               

              Regarding to the HVAC unit, I’m trying to simulate the air movements inside it, but still I don’t have satisfactory results (because I have air filters, a coil…).

              From experimental data I have the drop pressure – volume flow rate curve of the HVAC unit. So I know the inlet pressure for the fan for each volume flow rate à the inlet pressure depends on the volume flow rate.

               

              I have to find the only volume flow rate that satisfies:

              "Drop pressure at the HVAC unit for this flow rate + Drop pressure at the duct for this flow rate = Fan drop pressure for this flow rate according to its curve"

               

              I have found this point iterating, changing manually the inlet pressure till the volume flow rate agrees the "equation"

               

              Thanks,

               

              Teresa