Water Detailed Flow - MapleSim Help
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Water Detailed Flow

Detailed flow calculation of Water

 

 

Description

Equations

Variables

Connections

Parameters

See Also

Description

The Water Detailed Flow component models a flow calculation which is for Laminar and Turbulent for the lumped thermal fluid simulation of Water. This component calculates mainly pressure difference and mass flow rate.

 

Equations

The calculation is changed based on parameter values of Type of pipe, and Dynamics of mass in the Water Settings component

The definition of Inner hydraulic diameter and Flow area, Geometrical coefficient for laminar flow are explained in the following:

Type of pipe = General

Inner hydraulic diameter is defined with:

Flow area is defined with:

Geometrical coefficient for laminar flow is defined with:

Type of pipe = Circular

Inner hydraulic diameter is defined with:

Flow area is defined with:

Geometrical coefficient for laminar flow is defined with:

 

Type of pipe = Rectangular

Inner hydraulic diameter is defined with:

Flow area is defined with:

Geometrical coefficient for laminar flow is defined with:

(*)  is the function of Lookup table of 1D.

(*) data is specified with:

     - If data_source = inline, parameter .

     - If data_source = attachment, an attached file (.csv and .xls, .xlsx) is used

     - If data_source = file, need to specify the path of file (.csv and .xls, .xlsx).

 

Reynolds number is calculated with:

The friction factor of flow is calculated with:

(*) The above function  is to calculated friction factor for Laminar and Turbulent flow.
The fundamental implementation is based on the following equations. Especially, the equation of Turbulent flow is Swamee and Jain's approximation[1] .

(Reference) Detailed implementation of Friction factor calculation

Friction factor of Laminar flow is calculated with:

And, Turbulent flow's friction factor is defined with (Swamee and Jain's approximation):

Intermittency is defined with:

So, the friction factor is calculated with:

The following plot is Reynolds number vs Friction factor, and , , , .

 

The definition of Flow calculation is the following and:

Dynamics of mass = Static

Pressure difference is calculated with Darcy–Weisbach equation:

Dynamics of mass = Dynamic

In theory, Mass flow rate is calculated with Darcy–Weisbach equation:

In the Heat Transfer Library, the following equation is used to resolve difficulties of the numerical calculation:

(*)  is the same function as . To check the details of the package and view the original documentation, which includes author and copyright information, click here.

 

Definitions related to Mass flow rate and pressure:

Density is calculated with:

If Fidelity of properties = Constant, properties are calculated with:

(*) Regarding the value of properties for Constant, see more in Water Settings.

If Fidelity of properties = Liquid water (Lookup table of IAPWS/IF97), properties are calculated with:

(*) The properties are defined with Liquid water (Lookup table of IAPWS/IF97), see more in Water Settings.

If Fidelity of properties = IAPWS/IF97 standard, properties are calculated with:

(*) The properties are defined with IAPWS/IF97 standard, see more in Water Settings.

 

Port's variables are defined with:

References

[1] : Swamee P.K., Jain A.K. (1976): Explicit equations for pipe-flow problems. Proc. ASCE, J.Hydraul. Div., 102 (HY5), pp. 657-664.

 

Variables

Symbol

Units

Description

Modelica ID

Pressure difference

p

Mass flow rate

mflow

Velocity of flow

v

Inner hydraulic diameter used for Fluid simulation

Dh_act

Flow area used for Fluid simulation

A_act

Geometrical coefficient used for Fluid simulation

Geo_act

Reynolds number for Friction factor calculation

Re

Targeted Reynolds number for Friction factor calculation

Re_target

Friction factor

lambda

Friction factor for Laminar flow

lambda_lam

Friction factor for Turbulent flow

lambda_tur

Intermittency factor to calculate Transition zone

kappa

Density at port_a

rho_a

Density at port_b

rho_b

Dynamic viscosity at port_a

vis_a

Dynamic viscosity at port_b

vis_b

Connections

Name

Condition

Description

Modelica ID

 

Water Port

 

Water Port

if External input of Geometrical coefficient = false

Geometrical coefficient input

Parameters

Symbol

Default

Units

Description

Modelica ID

Specify a component of Water simulation settings

Settings

Select pipe type

 - General

 - Circular pipe

 - Rectangular pipe

TypeOfPipe

Pipe length

L

Internal hydraulic diameter if Type of pipe is General or Circular.

Dh

Horizontal length only if Type of pipe = Rectangular.

a_rec

Vertical length only if Type of pipe = Rectangular.

b_rec

Flow area only if Type of pipe = General.

A

Absolute roughness of pipe, with a default for a smooth steel pipe

roughness

If true, Geometrical coefficient is defined by the input. And, if Type of pipe = Rectangular, this parameter is valid.

Geo_ext

Geometrical coefficient for Laminar flow only if Type of pipe = General and External input of Geometrical coefficient = false.

Geo

inline

-

See Data Source Options section above.

DSM_geo_rec

Geometrical coefficient for Rectangular pipe, if  = inline.

[1] :Volume flow rate

[2] :Pressure difference

table_geo_rec

-

Geometrical coefficient for Rectangular pipe, if  =file or attachment. You can specify data by using an attached file or specifying the path of file (.csv and .xls, .xlsx)

data_geo_rec

-

Determines which columns of the data table will be used to interpolate.

For example, in an Excel spreadsheet, column A corresponds with 1, column B corresponds with 2, and so on.

columns_geo_rec

0

-

Number of rows that are skipped from the top of the data table.

skiprows_geo_rec

Table points are linearly interpolated

-

Determines whether the data points will be interpolated linearly or with a cubic spline.

smoothness_geo_rec

Approximation of function for |dp| <= dp_small

dp_small

Sharpness of approximation for sqrt(dp) and sqrt(rho * dp)

sharpness

Time constant for Reynolds number calculation

T_const

Reynolds number of the center of Transition zone

Re_CoT

Changing rate of Intermittency factor

IF_spread

See Also

Heat Transfer Library Overview

Water Overview

Water Shapes Overview

 


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