Kada plin struji u cijevnoj mreži njegova gustoća, temperatura i brzina se mjenja kako teče kroz mrežu.

Rješenju se pristupa često koristeći literaturu da bi se pretpostavio idealni plinski zakon, tako da analitičke jednadžbe za energiju, momente i kontinuitet mogu biti dobivene. Umjesto da pojednostavi pretpostavke FluidFlow3 koristi proceduru koja rješava konzervativnu jednađžbu zajedno sa jednadžbom za male gubitke tlakova. To znači da FluidFlow dobiva rigorozno rješenje.

Dostupne jednadžbe stanja su:

    • Benedict-Webb-Rubin-ova
    • Peng-Robinson-ova
    • Lee Kesler-ova

Dinamički scenarij kompresorske sobe

gascalculation1

Ovaj primjer pokazuje komprimiranje zraka i “receiver system”.

Kompresori, filteri za zrak, recivers, sušilice i sustavi za rasterećenje mogu biti uključeni u istom modelu.

Dinamički scenarij najbolj.

Gas Results

gasresults1

Consider the tabular results for the fan discharge pipe as shown opposite. Along the flowpath the gas expands, the temperature and density decreases, while the velocity and actual flow increases. This is the case if no heat transfer occurs, FluidFlow3 can also take heat transfer considerations into account.

You may also notice that we are displaying 3 volumetric flows in the results table. The first flow refers to the actual flow at the start of the pipe (remember the actual volumetric flow increases as gas flows down the pipe), the other flow rates show volumetric flow with reference to standard and normal conditions.

Gas Chart Results

gaschartresults

For gas flow within a pipe, the pressure and temperature conditions continuously change. This means that the gas physical properties of density, viscosity, heat capacity, thermal conductivity, sonic velocity, etc., change with pipe length.

The curve opposite shows the change in gas density as we flow down this pipe. This underlines the importance of using an appropriate calculation method. Imagine the error that would be introduced if you assumed density was constant.

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