functioninternal_pipe_ASHRAE
Extends from Modelica.Icons.Function (Icon for functions).
Information
The following Dittus and Boelter (1930) correlation is applicable for a fully turbulent internal flows in pipes. The formula is picked from the ASHRAE guide chapter 3 table 9 equation T9.5 and 9.6
The correlation is given for a Reynolds number Re > 104.
The value of the exponent over the Prandtl number depends on whether the pipe wall is warmer or colder than the fluid.
If the pipe is warmer (heating mode), n = 4 and n = 3 (cooling mode) otherwise.
Where :
- Nu is the Nusselt number
- Re is the Reynolds number
- Pr is the Prandtl number
- DeltaT is the temperature difference between the wall and the fluid
Inputs
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.SIunits.PrandtlNumber | Pr | ||
| Modelica.SIunits.ReynoldsNumber | Re | ||
| Modelica.SIunits.TemperatureDifference | dT |
Outputs
| Type | Name | Default | Description |
|---|---|---|---|
| Modelica.SIunits.NusseltNumber | Nu |