Package for generic pressure loss calculations
Information
General
General pressure loss for ideal gas
Calculation of a generic pressure loss for an ideal gas using mean density.
See more information.
Generic pressure loss depending on density and viscosity
Calculation of a generic pressure loss in dependence of nominal fluid variables (e.g., nominal density, nominal dynamic viscosity) at an operation point via interpolation.
This generic function considers the pressure loss law via a pressure loss exponent and the influence of density and dynamic viscosity on pressure loss.
See more information.
Generic pressure loss depending on density
Calculation of a generic pressure loss in dependence of nominal fluid variables (e.g., nominal density) via interpolation from an operation point.
See more information.
Generic pressure loss depending on pressure loss coefficient
Calculation of a generic pressure loss in dependence of a pressure loss coefficient.
See more information.
Generic pressure loss depending on volume flow rate
Calculation of a generic pressure loss with linear or quadratic dependence on volume flow rate.
See more information.
Extends from Modelica.Icons.VariantsPackage (Icon for package containing variants).
Package Content
Generic pressure loss | calculate pressure loss | ideal gas | mean density
Information
Calculation of a generic pressure loss for an ideal gas using mean density.
Generally this function is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. On the other hand the function dp_idealGas_MFLOW is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| Pressure | DP | Output for function dp_idealGas_DP [Pa] |
Modelica definition
function dp_idealGas_DP
"Generic pressure loss | calculate pressure loss | ideal gas | mean density"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_idealGas_IN_con
IN_con "Input record for function dp_idealGas_DP";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_idealGas_IN_var
IN_var "Input record for function dp_idealGas_DP";
input SI.MassFlowRate m_flow "Mass flow rate";
//output variables
output SI.Pressure DP "Output for function dp_idealGas_DP";
protected
Real Km_internal=IN_con.Km "Coefficient for pressure loss";
SI.Density rho_internal=IN_var.p_m/(IN_con.R_s*IN_var.T_m) "Mean density";
SI.VolumeFlowRate V_flow=m_flow/rho_internal "Volume flow rate [m3/s]";
SI.VolumeFlowRate V_flow_min=(IN_con.R_s/Km_internal)^(1/IN_con.exp)*
rho_internal^(1/IN_con.exp - 1)*IN_con.dp_smooth^(1/IN_con.exp)
"Start of approximation for decreasing volume flow rate";
//Documentation
algorithm
DP := (Km_internal/IN_con.R_s)*(rho_internal)^(IN_con.exp - 1)*
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
V_flow,
V_flow_min,
IN_con.exp);
end dp_idealGas_DP;
Generic pressure loss | calculate mass flow rate | ideal gas | mean density
Information
Calculation of a generic pressure loss for an ideal gas using mean density.
Generally this function is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. On the other hand the function dp_idealGas_DP is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. See more information.
Inputs
| Type | Name | Default | Description |
|---|
| Constant inputs |
| dp_idealGas_IN_con | IN_con | | Input record for function dp_idealGas_MFLOW |
| Variable inputs |
| dp_idealGas_IN_var | IN_var | | Input record for function dp_idealGas_MFLOW |
| Input |
| Pressure | dp | | Pressure loss [Pa] |
Outputs
| Type | Name | Description |
|---|
| MassFlowRate | M_FLOW | Output for function dp_idealGas_MFLOW [kg/s] |
Modelica definition
function dp_idealGas_MFLOW
"Generic pressure loss | calculate mass flow rate | ideal gas | mean density"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_idealGas_IN_con
IN_con "Input record for function dp_idealGas_MFLOW";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_idealGas_IN_var
IN_var "Input record for function dp_idealGas_MFLOW";
input SI.Pressure dp "Pressure loss";
//output variables
output SI.MassFlowRate M_FLOW "Output for function dp_idealGas_MFLOW";
protected
Real Km_internal=IN_con.Km "Coefficient for pressure loss";
SI.Density rho_internal=IN_var.p_m/(IN_con.R_s*IN_var.T_m) "Mean density";
//Documentation
algorithm
M_FLOW := (IN_con.R_s/Km_internal)^(1/IN_con.exp)*(rho_internal)^(1/
IN_con.exp)*Dissipation.Utilities.Functions.General.SmoothPower(
dp,
IN_con.dp_smooth,
1/IN_con.exp);
end dp_idealGas_MFLOW;
Input record for function dp_idealGas_DP and dp_idealGas_MFLOW
Information
This record is used as input record for the pressure loss function
dp_idealGas_DP and
dp_idealGas_MFLOW .
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.IdealGas_con (Base record for generic pressure loss function | ideal gas | mean density).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| Real | exp | 2 | Exponent of pressure loss law |
| Real | Km | 6824.86 | Coefficient for pressure loss law [(Pa)^2/{(kg/s)^exp*K}] |
| Fluid properties |
| SpecificHeatCapacity | R_s | | Specific gas constant of ideal gas [J/(kg.K)] |
| Linearisation |
| Pressure | dp_smooth | 1 | Start linearisation for smaller pressure loss [Pa] |
Modelica definition
record dp_idealGas_IN_con
"Input record for function dp_idealGas_DP and dp_idealGas_MFLOW"
//generic variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.IdealGas_con;
//linearisation
SI.Pressure dp_smooth(min=Modelica.Constants.eps) = 1
"Start linearisation for smaller pressure loss";
end dp_idealGas_IN_con;
Input record for function dp_idealGas_DP and dp_idealGas_MFLOW
Information
This record is used as input record for the pressure loss function
dp_idealGas_DP and
dp_idealGas_MFLOW.
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.IdealGas_var (Base record for generic pressure loss function | ideal gas | mean density).
Parameters
| Type | Name | Default | Description |
|---|
| Fluid properties |
| Density | rho_m | | Mean density of ideal gas [kg/m3] |
| Temp_K | T_m | | Mean temperature of ideal gas [K] |
| Pressure | p_m | | Mean pressure of ideal gas [Pa] |
Modelica definition
record dp_idealGas_IN_var
"Input record for function dp_idealGas_DP and dp_idealGas_MFLOW"
//generic variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.IdealGas_var;
end dp_idealGas_IN_var;
Generic pressure loss | calculate mass flow rate | nominal operation point | pressure loss law (exponent) | density and dynamic viscosity dependence
Information
Calculation of a generic pressure loss in dependence of nominal fluid variables (e.g., nominal density, nominal dynamic viscosity) at an operation point via interpolation.
This generic function considers the pressure loss law via a pressure loss exponent and the influence of density and dynamic viscosity on pressure loss.
Generally this function is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. On the other hand the function dp_nominalDensityViscosity_MFLOW is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| Pressure | DP | Output for function dp_nominalDensityViscosity_DP [Pa] |
Modelica definition
function dp_nominalDensityViscosity_DP
"Generic pressure loss | calculate mass flow rate | nominal operation point | pressure loss law (exponent) | density and dynamic viscosity dependence"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalDensityViscosity_IN_con
IN_con "Input record for function dp_nominalDensityViscosity_DP";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalDensityViscosity_IN_var
IN_var "Input record for function dp_nominalDensityViscosity_DP";
input SI.MassFlowRate m_flow "Mass flow rate";
//output variables
output SI.Pressure DP "Output for function dp_nominalDensityViscosity_DP";
protected
SI.MassFlowRate m_flow_smooth=(max(1, 0.01*IN_con.dp_nom)*IN_var.rho/IN_con.rho_nom
*(1/IN_var.eta*IN_con.eta_nom)^(IN_con.exp_eta)*(1/IN_con.m_flow_nom))^(1
/IN_con.exp) "Start of approximation for decreasing mass flow rate";
//Documentation
algorithm
DP := if IN_con.exp > 1.0 or IN_con.exp < 1.0 then
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
m_flow,
m_flow_smooth,
IN_con.exp)*(IN_var.eta/IN_con.eta_nom)^IN_con.exp_eta*IN_con.rho_nom
/IN_var.rho*IN_con.dp_nom*(1/IN_con.m_flow_nom)^(IN_con.exp) else
m_flow/IN_con.m_flow_nom*(IN_var.eta/IN_con.eta_nom)^IN_con.exp_eta*
IN_con.rho_nom/IN_var.rho*IN_con.dp_nom;
end dp_nominalDensityViscosity_DP;
Generic pressure loss | calculate M_FLOW (compressible) | nominal operation point | pressure loss law (exponent) | density and dynamic viscosity dependence
Information
Calculation of a generic pressure loss in dependence of nominal fluid variables (e.g., nominal density, nominal dynamic viscosity) at an operation point via interpolation.
This generic function considers the pressure loss law via a pressure loss exponent and the influence of density and dynamic viscosity on pressure loss.
Generally this function is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. On the other hand the function dp_genericDensityViscosity_DP is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| MassFlowRate | M_FLOW | Output for function dp_nominalDensityViscosity_MFLOW [kg/s] |
Modelica definition
function dp_nominalDensityViscosity_MFLOW
"Generic pressure loss | calculate M_FLOW (compressible) | nominal operation point | pressure loss law (exponent) | density and dynamic viscosity dependence"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalDensityViscosity_IN_con
IN_con "Input record for function dp_nominalDensityViscosity_MFLOW";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalDensityViscosity_IN_var
IN_var "Input record for function dp_nominalDensityViscosity_MFLOW";
input SI.Pressure dp "Pressure loss";
//output variables
output SI.MassFlowRate M_FLOW
"Output for function dp_nominalDensityViscosity_MFLOW";
//Documentation
algorithm
M_FLOW := if IN_con.exp > 1.0 or IN_con.exp < 1.0 then
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
dp,
0.01*IN_con.dp_nom,
1/IN_con.exp)*(IN_con.eta_nom/IN_var.eta)^(IN_con.exp_eta/
IN_con.exp)*(1/IN_con.dp_nom*IN_var.rho/IN_con.rho_nom)^(1/IN_con.exp)
*IN_con.m_flow_nom else dp/IN_con.dp_nom*(IN_con.eta_nom/IN_var.eta)^
(IN_con.exp_eta)*IN_var.rho/IN_con.rho_nom*IN_con.m_flow_nom;
end dp_nominalDensityViscosity_MFLOW;
Output record for function dp_nominalDensityViscosity_DP and dp_nominalDensityViscosity_MFLOW
Information
This record is used as input record for the pressure loss function
dp_nominalDensityViscosity_DP and
dp_nominalDensityViscosity_MFLOW.
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.NominalDensityViscosity (Base record for generic pressure loss function).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| Pressure | dp_nom | 2 | Nominal pressure loss (at nominal values of mass flow rate and density) [Pa] |
| Real | exp | 2 | Exponent of pressure loss law |
| MassFlowRate | m_flow_nom | 1 | Nominal mass flow rate (at nominal values of pressure loss and density) [kg/s] |
| Density | rho_nom | | Nominal density (at nominal values of mass flow rate and pressure loss) [kg/m3] |
| Real | exp_eta | 1 | Exponent for dynamic viscosity dependence |
| DynamicViscosity | eta_nom | | Dynamic viscosity at nominal pressure loss [Pa.s] |
Modelica definition
record dp_nominalDensityViscosity_IN_con
"Output record for function dp_nominalDensityViscosity_DP and dp_nominalDensityViscosity_MFLOW"
//generic variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.NominalDensityViscosity;
end dp_nominalDensityViscosity_IN_con;
Output record for function dp_nominalDensityViscosity_DP and dp_nominalDensityViscosity_MFLOW
Information
This record is used as input record for the pressure loss function
dp_nominalDensityViscosity_DP and
dp_nominalDensityViscosity_MFLOW.
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.PressureLoss (Base record for fluid properties for pressure loss).
Parameters
| Type | Name | Default | Description |
|---|
| Fluid properties |
| DynamicViscosity | eta | | Dynamic viscosity of fluid [Pa.s] |
| Density | rho | | Density of fluid [kg/m3] |
Modelica definition
record dp_nominalDensityViscosity_IN_var
"Output record for function dp_nominalDensityViscosity_DP and dp_nominalDensityViscosity_MFLOW"
//fluid property variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.PressureLoss;
end dp_nominalDensityViscosity_IN_var;
Generic pressure loss | calculate pressure loss | nominal operation point | pressure loss law (coefficient and exponent) | density dependence
Information
Calculation of a generic pressure loss in dependence of nominal fluid variables (e.g., nominal density) via interpolation from an operation point.
This generic function considers the pressure loss law via a nominal pressure loss (dp_nom), a pressure loss coefficient (zeta_TOT) and a pressure loss law exponent (exp) as well as the influence of density on pressure loss.
Generally this function is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. On the other hand the function dp_nominalPressureLossLawDensity_MFLOW is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| Pressure | DP | Output for function dp_nominalPressureLossLawDensity_yesAJac_DP [Pa] |
Modelica definition
function dp_nominalPressureLossLawDensity_DP
"Generic pressure loss | calculate pressure loss | nominal operation point | pressure loss law (coefficient and exponent) | density dependence"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalPressureLossLawDensity_IN_con
IN_con "Input record for function dp_nominalPressureLossLawDensity_DP";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalPressureLossLawDensity_IN_var
IN_var "Input record for function dp_nominalPressureLossLawDensity_DP";
input SI.MassFlowRate m_flow "Mass flow rate";
//output variables
output SI.Pressure DP
"Output for function dp_nominalPressureLossLawDensity_yesAJac_DP";
protected
Real exp_density=if IN_con.target ==Dissipation.Utilities.Types.MassOrVolumeFlowRate.MassFlowRate then
1 - IN_con.exp else 1 "Exponent of density fraction (rho/rho_nom)";
SI.MassFlowRate m_flow_nom=if IN_con.target ==Dissipation.Utilities.Types.MassOrVolumeFlowRate.MassFlowRate then
IN_con.m_flow_nom else IN_var.rho*IN_con.V_flow_nom
"Nominal mean flow velocity at operation point";
SI.MassFlowRate m_flow_linear=(0.01*(IN_con.zeta_TOT_nom/IN_var.zeta_TOT)*(
IN_con.rho_nom/IN_var.rho)^(exp_density)*(IN_con.A_cross/IN_con.A_cross_nom)
^(IN_con.exp)*IN_con.m_flow_nom)^(1/IN_con.exp)
"Start of approximation for decreasing mass flow rate";
//Documentation
algorithm
DP := if IN_con.exp > 1.0 or IN_con.exp < 1.0 then
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
m_flow,
m_flow_linear,
IN_con.exp)*IN_con.dp_nom*(IN_var.zeta_TOT/IN_con.zeta_TOT_nom)
*(IN_var.rho/IN_con.rho_nom)^(exp_density)*(IN_con.A_cross_nom/IN_con.A_cross)
^(IN_con.exp)*(1/IN_con.m_flow_nom)^(IN_con.exp) else IN_con.dp_nom*(
IN_var.zeta_TOT/IN_con.zeta_TOT_nom)*(IN_var.rho/IN_con.rho_nom)^(
exp_density)*(IN_con.A_cross_nom/IN_con.A_cross)^(1)*(m_flow/IN_con.m_flow_nom)
^(1);
end dp_nominalPressureLossLawDensity_DP;
Generic pressure loss | calculate mass flow rate | nominal operation point | pressure loss law (coefficient and exponent) | density dependence
Information
Calculation of a generic pressure loss in dependence of nominal fluid variables (e.g., nominal density) via interpolation from an operation point.
This generic function considers the pressure loss law via a nominal pressure loss (dp_nom), a pressure loss coefficient (zeta_TOT) and a pressure loss law exponent (exp) as well as the influence of density on pressure loss.
Generally this function is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. On the other hand the function dp_nominalPressurelosslawDensity_DP is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| MassFlowRate | M_FLOW | Output for function dp_nominalPressurelosslawDensity_MFLOW [kg/s] |
Modelica definition
function dp_nominalPressureLossLawDensity_MFLOW
"Generic pressure loss | calculate mass flow rate | nominal operation point | pressure loss law (coefficient and exponent) | density dependence"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalPressureLossLawDensity_IN_con
IN_con "Input record for function dp_nominalPressureLossLawDensity_MFLOW";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalPressureLossLawDensity_IN_var
IN_var "Input record for function dp_nominalPressureLossLawDensity_MFLOW";
input SI.Pressure dp "Pressure loss";
//output variables
output SI.MassFlowRate M_FLOW
"Output for function dp_nominalPressurelosslawDensity_MFLOW";
protected
Real exp_density=if IN_con.target ==Dissipation.Utilities.Types.MassOrVolumeFlowRate.MassFlowRate then
1 - IN_con.exp else 1 "Exponent of density fraction (rho/rho_nom)";
SI.MassFlowRate m_flow_nom=if IN_con.target ==Dissipation.Utilities.Types.MassOrVolumeFlowRate.MassFlowRate then
IN_con.m_flow_nom else IN_var.rho*IN_con.V_flow_nom
"Nominal mean flow velocity at operation point";
//Documentation
algorithm
M_FLOW := if IN_con.exp > 1.0 or IN_con.exp < 1.0 then
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
dp,
0.01*IN_con.dp_nom,
1/IN_con.exp)*IN_con.m_flow_nom*(IN_con.A_cross/IN_con.A_cross_nom)
*(IN_con.rho_nom/IN_var.rho)^(exp_density/IN_con.exp)*((1/IN_con.dp_nom)
*(IN_con.zeta_TOT_nom/IN_var.zeta_TOT))^(1/IN_con.exp) else IN_con.m_flow_nom
*(IN_con.A_cross/IN_con.A_cross_nom)*(IN_con.rho_nom/IN_var.rho)^(
exp_density/1)*((dp/IN_con.dp_nom)*(IN_con.zeta_TOT_nom/IN_var.zeta_TOT))
^(1/1);
end dp_nominalPressureLossLawDensity_MFLOW;
Input record for function dp_nominalPressureLossLawDensity_DP and dp_nominalPressureLossLawDensity_MFLOW
Information
This record is used as input record for the pressure loss function
dp_nominalPressureLosslawDensity_DP and
dp_nominalPressureLosslawDensity_MFLOW.
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.NominalPressureLossLawDensity_con (Base record for generic pressure loss function).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| MassOrVolumeFlowRate | target | Dissipation.Utilities.Types.... | 1 == use nominal mass flow rate | 2 == use nominal volume flow rate |
| Area | A_cross | A_cross_nom | Cross sectional area [m2] |
| Area | A_cross_nom | Modelica.Constants.pi*0.1^2/4 | Nominal cross sectional area [m2] |
| Pressure | dp_nom | 2 | Nominal pressure loss (at nominal values of mass flow rate and density) [Pa] |
| MassFlowRate | m_flow_nom | 1 | Nominal mass flow rate (at nominal values of pressure loss and density) [kg/s] |
| Real | exp | 2 | Exponent of pressure loss law |
| VolumeFlowRate | V_flow_nom | m_flow_nom/rho_nom | Nominal volume flow rate (at nominal values of pressure loss and density) [m3/s] |
| Density | rho_nom | | Nominal density (at nominal values of mass flow rate and pressure loss) [kg/m3] |
| PressureLossCoefficient | zeta_TOT_nom | 0.02*1/0.1 | Nominal pressure loss coefficient (for nominal values) [1] |
Modelica definition
record dp_nominalPressureLossLawDensity_IN_con
"Input record for function dp_nominalPressureLossLawDensity_DP and dp_nominalPressureLossLawDensity_MFLOW"
//generic variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.NominalPressureLossLawDensity_con;
end dp_nominalPressureLossLawDensity_IN_con;
Input record for function dp_nominalPressureLossLawDensity_DP and dp_nominalPressureLossLawDensity_MFLOW
Information
This record is used as input record for the pressure loss function
dp_nominalPressureLosslawDensity_DP and
dp_nominalPressureLosslawDensity_MFLOW.
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.NominalPressureLossLawDensity_var (Base record for generic pressure loss function).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| PressureLossCoefficient | zeta_TOT | 0.2 | Pressure loss coefficient [1] |
| Fluid properties |
| Density | rho | | Density of fluid [kg/m3] |
Modelica definition
record dp_nominalPressureLossLawDensity_IN_var
"Input record for function dp_nominalPressureLossLawDensity_DP and dp_nominalPressureLossLawDensity_MFLOW"
//generic variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.NominalPressureLossLawDensity_var;
//fluid property variables
SI.Density rho "Density of fluid";
end dp_nominalPressureLossLawDensity_IN_var;
Generic pressure loss | calculate pressure loss | pressure loss coefficient (zeta_TOT)
Information
Calculation of a generic pressure loss in dependence of a pressure loss coefficient.
Generally this function is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. On the other hand the function dp_pressureLossCoefficient_MFLOW is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| Pressure | DP | Output for function dp_pressureLossCoefficient_DP [Pa] |
Modelica definition
function dp_pressureLossCoefficient_DP
"Generic pressure loss | calculate pressure loss | pressure loss coefficient (zeta_TOT)"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_pressureLossCoefficient_IN_con
IN_con "Input record for dp_pressureLossCoefficient_DP";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_pressureLossCoefficient_IN_var
IN_var "Input record for dp_pressureLossCoefficient_DP";
input SI.MassFlowRate m_flow "Mass flow rate";
//output variables
output SI.Pressure DP "Output for function dp_pressureLossCoefficient_DP";
//Documentation
algorithm
DP := 0.5*IN_var.zeta_TOT*
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
m_flow,
(IN_con.dp_smooth/(0.5*IN_var.zeta_TOT*IN_var.rho))^0.5*IN_var.rho
*IN_con.A_cross,
2)/(IN_var.rho*(IN_con.A_cross)^2);
end dp_pressureLossCoefficient_DP;
Generic pressure loss | calculate mass flow rate | pressure loss coefficient (zeta_TOT)
Information
Calculation of a generic pressure loss in dependence of a pressure loss coefficient.
Generally this function is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. On the other hand the function dp_pressureLossCoefficient_DP is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| MassFlowRate | M_FLOW | Output for function dp_pressureLossCoefficientt_MFLOW [kg/s] |
Modelica definition
function dp_pressureLossCoefficient_MFLOW
"Generic pressure loss | calculate mass flow rate | pressure loss coefficient (zeta_TOT)"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_pressureLossCoefficient_IN_con
IN_con "Input record for function dp_pressureLossCoefficient_MFLOW";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_pressureLossCoefficient_IN_var
IN_var "Input record for function dp_pressureLossCoefficient_MFLOW";
input SI.Pressure dp "Pressure loss";
//output variables
output SI.MassFlowRate M_FLOW
"Output for function dp_pressureLossCoefficientt_MFLOW";
//Documentation
algorithm
M_FLOW := IN_var.rho*IN_con.A_cross*
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
dp,
IN_con.dp_smooth,
0.5)/(0.5*IN_var.zeta_TOT*IN_var.rho)^0.5;
end dp_pressureLossCoefficient_MFLOW;
Input record for function dp_pressureLossCoefficient_DP and dp_pressureLossCoefficient_MFLOW
Information
This record is used as input record for the pressure loss function
dp_pressureLossCoefficient_DP and
dp_pressureLossCoefficient_MFLOW.
Extends from Modelica.Icons.Record (Icon for records).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| Area | A_cross | Modelica.Constants.pi*0.1^2/4 | Cross sectional area [m2] |
| Linearisation |
| Pressure | dp_smooth | 1 | Start linearisation for decreasing pressure loss [Pa] |
Modelica definition
record dp_pressureLossCoefficient_IN_con
"Input record for function dp_pressureLossCoefficient_DP and dp_pressureLossCoefficient_MFLOW"
extends Modelica.Icons.Record;
//generic variables
SI.Area A_cross=Modelica.Constants.pi*0.1^2/4 "Cross sectional area";
//linearisation
SI.Pressure dp_smooth=1 "Start linearisation for decreasing pressure loss";
end dp_pressureLossCoefficient_IN_con;
Input record for function dp_pressureLossCoefficient_DP and dp_pressureLossCoefficient_MFLOW
Information
This record is used as input record for the pressure loss function
dp_pressureLossCoefficient_DP and
dp_pressureLossCoefficient_MFLOW.
Extends from Modelica.Icons.Record (Icon for records).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| PressureLossCoefficient | zeta_TOT | 0.02*1/0.1 | Pressure loss coefficient [1] |
| FluidProperties |
| Density | rho | | Density of fluid [kg/m3] |
Modelica definition
record dp_pressureLossCoefficient_IN_var
"Input record for function dp_pressureLossCoefficient_DP and dp_pressureLossCoefficient_MFLOW"
extends Modelica.Icons.Record;
//generic variables
TYP.PressureLossCoefficient zeta_TOT=0.02*1/0.1 "Pressure loss coefficient";
//fluid property variables
SI.Density rho "Density of fluid";
end dp_pressureLossCoefficient_IN_var;
Generic pressure loss | calculate pressure loss | quadratic function (dp=a*V_flow^2 + b*V_flow)
Information
Calculation of a generic pressure loss with linear or quadratic dependence on volume flow rate.
The function can be used to calculate pressure loss at known mass flow rate or mass flow rate at known pressure loss.
Generally this function is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. On the other hand the function dp_volumeFlowRate_MFLOW is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| Pressure | DP | Output for function dp_volumeFlowRate_DP [Pa] |
Modelica definition
function dp_volumeFlowRate_DP
"Generic pressure loss | calculate pressure loss | quadratic function (dp=a*V_flow^2 + b*V_flow)"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_volumeFlowRate_IN_con
IN_con "Input record for function dp_volumeFlowRate_DP";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_volumeFlowRate_IN_var
IN_var "Input record for function dp_volumeFlowRate_DP";
input SI.MassFlowRate m_flow "Mass flow rate";
//output variables
output SI.Pressure DP "Output for function dp_volumeFlowRate_DP";
protected
Real a=max(Modelica.Constants.eps, abs(IN_con.a));
Real b=max(Modelica.Constants.eps, abs(IN_con.b));
SI.VolumeFlowRate V_flow=m_flow/max(Modelica.Constants.eps, IN_var.rho)
"Volume flow rate";
SI.Pressure dp_min=IN_con.dp_min
"Start of approximation for decreasing pressure loss";
SI.VolumeFlowRate V_flow_smooth=if IN_con.a > 0 then -(b/(2*a) + ((-b/(2*a))^
2 + dp_min/a)^0.5) else dp_min/b
"Start of approximation for decreasing volume flow rate";
//Documentation
algorithm
DP := a*Dissipation.Utilities.Functions.General.SmoothPower(
V_flow,
V_flow_smooth,
2) + b*V_flow;
end dp_volumeFlowRate_DP;
Generic pressure loss | calculate mass flow rate | quadratic function (dp=a*V_flow^2 + b*V_flow)
Information
Calculation of a generic pressure loss with linear or quadratic dependence on volume flow rate.
The function can be used to calculate pressure loss at known mass flow rate or mass flow rate at known pressure loss.
Generally this function is numerically best used for the compressible case if the pressure loss (dp) is known (out of pressures as state variable) and the mass flow rate (M_FLOW) has to be calculated. On the other hand the function dp_volumeFlowRate_DP is numerically best used for the incompressible case , where the mass flow rate (m_flow) is known (as state variable) in the used model and the corresponding pressure loss (DP) has to be calculated. See more information.
Inputs
Outputs
| Type | Name | Description |
|---|
| MassFlowRate | M_FLOW | Output for function dp_volumeFlowRate_MFLOW [kg/s] |
Modelica definition
function dp_volumeFlowRate_MFLOW
"Generic pressure loss | calculate mass flow rate | quadratic function (dp=a*V_flow^2 + b*V_flow)"
import FD = Modelica.Fluid.Dissipation.PressureLoss.General;
//input records
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_volumeFlowRate_IN_con
IN_con "Input record for function dp_volumeFlowRate_MFLOW";
input Modelica.Fluid.Dissipation.PressureLoss.General.dp_volumeFlowRate_IN_var
IN_var "Input record for function dp_volumeFlowRate_MFLOW";
input SI.Pressure dp "Pressure loss";
//output variables
output SI.MassFlowRate M_FLOW "Output for function dp_volumeFlowRate_MFLOW";
protected
Real a=max(Modelica.Constants.eps, abs(IN_con.a));
Real b=max(Modelica.Constants.eps, abs(IN_con.b));
SI.Pressure dp_min=IN_con.dp_min
"Start of approximation for decreasing pressure loss";
//Documentation
algorithm
M_FLOW := IN_var.rho*(-b/(2*a) +
Modelica.Fluid.Dissipation.Utilities.Functions.General.SmoothPower(
(b/(2*a))^2 + (1/a)*dp,
(b/(2*a))^2 + (1/a)*dp_min,
0.5));
end dp_volumeFlowRate_MFLOW;
Input record for function dp_volumeFlowRate_DP and dp_volumeFlowRate_MFLOW
Information
This record is used as input record for the pressure loss function
dp_volumeFlowRate_DP and
dp_volumeFlowRate_MFLOW.
Extends from Modelica.Fluid.Dissipation.Utilities.Records.General.QuadraticVFLOW (Base record for generic pressure loss function | quadratic function (dp=a*Vdot^2 + b*Vdot)).
Parameters
| Type | Name | Default | Description |
|---|
| Generic variables |
| Real | a | 15 | Coefficient for quadratic term [(Pa.s2)/m6] |
| Real | b | 0 | Coefficient for linear term [(Pa.s)/m3] |
Modelica definition
record dp_volumeFlowRate_IN_con
"Input record for function dp_volumeFlowRate_DP and dp_volumeFlowRate_MFLOW"
//generic variables
extends Modelica.Fluid.Dissipation.Utilities.Records.General.QuadraticVFLOW;
SI.Pressure dp_min=0.1 "Start of approximation for decreasing pressure loss";
end dp_volumeFlowRate_IN_con;
Input record for function dp_volumeFlowRate_DP and dp_volumeFlowRate_MFLOW
Information
This record is used as input record for the pressure loss function
dp_volumeFlowRate_DP and
dp_volumeFlowRate_MFLOW.
Parameters
| Type | Name | Default | Description |
|---|
| Fluid properties |
| Density | rho | | Density of fluid [kg/m3] |
Modelica definition
record dp_volumeFlowRate_IN_var
"Input record for function dp_volumeFlowRate_DP and dp_volumeFlowRate_MFLOW"
SI.Density rho "Density of fluid";
end dp_volumeFlowRate_IN_var;
Automatically generated Fri Nov 12 16:31:22 2010.
dp_idealGas_DP
dp_idealGas_IN_con
dp_nominalDensityViscosity_DP
dp_nominalDensityViscosity_IN_con
dp_nominalPressureLossLawDensity_DP
dp_nominalPressureLossLawDensity_IN_con
dp_pressureLossCoefficient_DP
dp_pressureLossCoefficient_IN_con
dp_volumeFlowRate_DP
dp_volumeFlowRate_IN_con
dp_volumeFlowRate_IN_var
Modelica.Fluid.Dissipation.PressureLoss.General.dp_idealGas_IN_con
Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalDensityViscosity_IN_con
Modelica.Fluid.Dissipation.PressureLoss.General.dp_nominalPressureLossLawDensity_IN_con
Modelica.Fluid.Dissipation.PressureLoss.General.dp_pressureLossCoefficient_IN_con
Modelica.Fluid.Dissipation.PressureLoss.General.dp_volumeFlowRate_IN_con