Fan (G)

R2026b

Fan in gas network

• 

Fan (G) block

To add a block to a model, double-click the canvas and start typing the block name. Then, select the block from the list.

Libraries:
Simscape / Fluids / Gas / Turbomachinery

Description

The Fan (G) block represents a fan in a gas network. You can model the torque and pressure gain over the fan as a function of static pressure and flow rate or by using 1D or 2D tabulated reference pressure, shaft speed, and flow rate data.

By default, flow and pressure gain are from port A to port B. Port C represents the fan casing, and port R represents the fan shaft. You can specify the normal operating shaft direction in the Mechanical orientation parameter. If the shaft begins to spin in the opposite direction, the pressure difference across the fan drops to zero.

Parameterization by Nominal Pressure, Flow Rate, and Shaft Speed

When you set the Fan parameterization parameter to Static pressure and flow rate at reference shaft speed, the block uses the analytical fan affinity laws and reference pressure differential to calculate the pressure gain from port A to port B:

$$p_B-p_A=\Delta p_{ref}{\left(\frac{\omega }{{\omega }_{ref}}\right)}^2{\left(\frac{D}{D_{ref}}\right)}^2,$$

where:

• Δp_ref is the reference pressure differential. The block uses a quadratic fit of the fan pressure differential values at the Maximum static pressure gain at zero flow, Nominal static pressure gain, and Maximum volumetric flow rate at zero pressure parameters.

• ω is the shaft angular velocity, ω_R – ω_C.

• ω_ref is the Reference shaft speed parameter.

• $$\frac{D}{D_{ref}}$$ is the Fan diameter scale factor parameter.

The block calculates the shaft torque from the reference mechanical power and the fan affinity laws:

$$\tau ={\Phi }_{ref}\frac{{\omega }^2}{{\omega }_{ref}^3}{\left(\frac{D}{D_{ref}}\right)}^5.$$

Where Φ_ref is the proportion of the pressure gain to the fan efficiency:

$${\Phi }_{ref}=\frac{q_{ref}\Delta p_{ref}}{{\eta }_{ref}}.$$

When you set the Shaft power specification parameter to Fan efficiency, the block uses a quadratic fit of efficiency between the fan peak performance, η_nom, and 0. η_nom is equivalent to the Nominal efficiency parameter, which the block interprets as the peak efficiency. If you set the Shaft power specification parameter to Brake power, the block derives the nominal fan efficiency from the nominal brake power, Φ_nom, at peak or nominal conditions:

$${\eta }_{nom}=\frac{q_{nom}\Delta p_{nom}}{{\Phi }_{nom}}.$$

The block assumes the efficiency is zero when there is no flow or when the flow reaches the maximum volumetric flow rate at zero pressure. The block uses the current flow q to compute the reference flow rate as:

$$q_{ref}=q\frac{{\omega }_{ref}}{\omega }{\left(\frac{D_{ref}}{D}\right)}^3.$$

1-D Tabulated Data Parameterization: Pressure as a Function of Flow Rate at Reference Shaft Speed

When you set the Fan parameterization parameter to 1D tabulated data - static pressure vs. flow rate at reference shaft speed, you can model fan performance as a function of volumetric flow rate. The block interpolates the pressure gain from port A to port B from the 1-D Static pressure gain vector parameter, Δp_ref(q_ref):

$$p_B-p_A=\Delta p_{ref}(q_{ref})\left(\frac{\rho }{{\rho }_{ref}}\right){\left(\frac{\omega }{{\omega }_{ref}}\right)}^2{\left(\frac{D}{D_{ref}}\right)}^2.$$

Here, ρ is the fluid density, and ρ_ref is the reference density, which is equivalent to the Reference density parameter. The block calculates the shaft torque from the reference mechanical power and the fan affinity laws:

$$\tau ={\Phi }_{ref}(q_{ref})\frac{{\omega }^2}{{\omega }_{ref}^3}\left(\frac{\rho }{{\rho }_{ref}}\right){\left(\frac{D}{D_{ref}}\right)}^5,$$

where ρ_ref is the Reference density.

The block uses the current flow q to compute the reference flow rate:

$$q_{ref}=q\frac{{\omega }_{ref}}{\omega }{\left(\frac{D_{ref}}{D}\right)}^3.$$

When the simulation is outside the range of the provided tables, the block extrapolates pressure based on the average slope of the fan curves and the reference torque to the nearest point.

2-D Tabulated Data Parameterization: Pressure as a Function of Shaft Speed and Flow Rate

When you set the Fan parameterization parameter to 2D tabulated data - static pressure vs. shaft speed and flow rate, you can model fan performance as a 2-D function of volumetric flow rate and angular velocity. The block interpolates the pressure gain from port A to port B from the 2-D Static pressure gain table, dp(w,q) parameter. The block defines the reference pressure gain, Δp_ref(q_ref,ω), as

$$p_B-p_A=\Delta p_{ref}(q_{ref},\omega )\left(\frac{\rho }{{\rho }_{ref}}\right){\left(\frac{D}{D_{ref}}\right)}^2.$$

The block calculates shaft torque from the reference mechanical power and the fan affinity laws:

$$\tau =\frac{{\Phi }_{ref}(q_{ref},\omega )}{\omega }\left(\frac{\rho }{{\rho }_{ref}}\right){\left(\frac{D}{D_{ref}}\right)}^5,$$

where the reference mechanical power is a function of the reference flow rate and the current shaft speed.

The block uses the current flow q to compute the reference flow rate:

$$q_{ref}=q{\left(\frac{D_{ref}}{D}\right)}^3.$$

When the simulation is outside the range of the provided tables, the block extrapolates pressure based on the average slope of the fan curves and the reference torque to the nearest point.

Missing Data

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Static pressure gain table, dp(w,q), Efficiency table, eta(w,q), and Mechanical power table, W(w,q) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

2-D Tabulated Data Parameterization: Flow Rate as a Function of Shaft Speed and Static Pressure

When you set the Fan parameterization parameter to 2D tabulated data - flow rate vs. shaft speed and static pressure, you can model the flow rate through the fan as a 2-D function of pressure and angular velocity. The volumetric flow rate is interpolated from the 2-D Volumetric flow rate table, q(w,dp) parameter, q_ref. The reference flow rate is a function of the reference pressure gain, Δp_ref, and the current shaft speed, ω:

$$q=q_{ref}(\Delta p_{ref},\omega ){\left(\frac{D}{D_{ref}}\right)}^3,$$

where the reference pressure gain derives from the pressure differential over the fan:

$$\Delta p_{ref}=\left(p_B-p_A\right)\left(\frac{{\rho }_{ref}}{\rho }\right){\left(\frac{D_{ref}}{D}\right)}^2.$$

The shaft torque derives from the reference mechanical power and the fan affinity laws:

$$\tau =\frac{{\Phi }_{ref}(\Delta p_{ref},\omega )}{\omega }\left(\frac{\rho }{{\rho }_{ref}}\right){\left(\frac{D}{D_{ref}}\right)}^5,$$

where the reference mechanical power is a function of the reference flow rate and the current shaft speed.

When the simulation is outside the range of the provided tables, the block extrapolates pressure based on the average slope of the fan curves and the reference torque to the nearest point.

Missing Data

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Volumetric flow rate table, q(w,dp), Efficiency table, eta(w,dp), and Mechanical power table, W(w,dp) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Power and Efficiency

You can specify shaft power by providing either fan efficiency or brake power.

The block calculates efficiency as

$$\eta =\frac{{\Phi }_{fluid}}{{\Phi }_{brake}},$$

where the brake power, or mechanical power measured at the shaft, is

$${\Phi }_{brake}=\tau \omega .$$

The block calculates fluid power as

$${\Phi }_{fluid}=q\left(p_B-p_A\right).$$

The block calculates torque as

$$\tau =\frac{{\Phi }_{brake}}{\omega }.$$

Visualizing the Fan Curve

You can check the parameterized fan performance by plotting the pressure, power, efficiency, and torque as a function of the flow. To generate a plot of the current fan settings, in the block dialog box, click the Plot button next to Fan characteristics. If you change settings or data, click Apply on the block parameters and click Reload Data on the fan curve figure.

The default block parameterization results in these plots:

Energy Balance

When you clear Model losses as heat transfer into fluid, the energy balance equation is

$${\varphi }_A+{\varphi }_B+P_{hydro}=0,$$

where:

• Φ_A is the energy flow rate at port A.

• Φ_B is the energy flow rate at port B.

The pump hydraulic power is a function of the pressure difference between pump ports,

$$P_{hydro}=\Delta p\frac{\dot{m}}{\rho }.$$

When you select Model losses as heat transfer into fluid, the energy balance equation is

$$\frac{d{p}_I}{dt}\frac{\partial U}{\partial p_I}+\frac{d{T}_I}{dt}\frac{\partial U}{\partial T_I}={\varphi }_A+{\varphi }_B+{\dot{W}}_{mech}+Q_H,$$

where:

• Q_H is the heat flow rate into port H.

• Ẇ_mech is the mechanical power.

• U is the fluid volume internal energy.

• p_I is the fluid volume pressure.

• T_I is the fluid volume temperature.

The fluid density is constant, which is ensured by the equation

$$\frac{\partial M}{\partial p_I}\frac{d{p}_I}{dt}+\frac{\partial M}{\partial T_I}\frac{d{T}_I}{dt}=0,$$

where M is the mass of the fluid volume.

The block uses the Nominal temperature and Nominal pressure parameters to calculate the nominal density, which the block uses to approximate the fluid volume density.

Assumptions and Limitations

• If the shaft rotates opposite to the specified mechanical orientation, the pressure difference across the block drops to zero and the results may not be accurate.

• The block assumes that the fan is quasi-steady.

• The block simulates fan performance in terms of static pressure rise, and not total fan pressure.

Examples

Model a Simple CPU Cooling System

Demonstrates a model of a simple CPU cooling system that consists of a CPU board, heat sink, fan controller, and cooling fan.

• Open Model

Ports

Conserving

A — Fluid entry

gas

Gas conserving port associated with the fluid.

Programmatic Use

Port: A

B — Fluid exit

gas

Gas conserving port associated with the fluid.

Programmatic Use

Port: B

R — Shaft

mechanical rotational

Mechanical rotational conserving port associated with the shaft.

Programmatic Use

Port: R

C — Casing

mechanical rotational

Mechanical rotational conserving port associated with the casing.

Programmatic Use

Port: C

H — Fluid volume

thermal

Thermal conserving port associated with the fluid volume.

Dependencies

To enable this port, select Model losses as heat transfer into fluid and Enable thermal port.

Programmatic Use

Port: H

Parameters

Performance

Fan parameterization — Fan performance model

Static pressure and flow rate at reference shaft speed (default) | 1D tabulated data - static pressure vs. flow rate at reference shaft speed | 2D tabulated data - static pressure vs. shaft speed and flow rate | 2D tabulated data - flow rate vs. shaft speed and static pressure

Fan performance model, specified as:

• Static pressure and flow rate at reference shaft speed: Specify fan performance based on typical, nominal, or rated pressure gain and volumetric flow rate.

• 1D tabulated data – static pressure vs flow rate at reference shaft speed: Specify fan performance based on interpolation of pressure gain data as a function of volumetric flow rate.

• 2D tabulated data – static pressure vs shaft speed and flow rate: Specify fan performance based on the interpolation of pressure gain data as a function of shaft speed and volumetric flow rate.

• 2D tabulated data – flow rate vs shaft speed and static pressure: Specify fan performance based on the interpolation of volumetric flow rate data as a function of shaft speed and pressure gain.

Programmatic Use

Parameter:	fan_parameterization
Values:	"fluids.gas.turbomachinery.enum.FanParameterization.Nominal" | "fluids.gas.turbomachinery.enum.FanParameterization.Table1D" | "fluids.gas.turbomachinery.enum.FanParameterization.Table2DPressure" | "fluids.gas.turbomachinery.enum.FanParameterization.Table2DFlowRate"

Shaft power specification — Power definition

Fan efficiency (default) | Brake power

Fan power specification, specified as:

• Fan efficiency: Derive the mechanical power from the fan efficiency.

• Mechanical power: Specify the mechanical power directly.

Programmatic Use

Parameter:	mechanical_power_spec
Values:	"fluids.gas.turbomachinery.enum.FanMechanicalPowerSpec.Efficiency" | "fluids.gas.turbomachinery.enum.FanMechanicalPowerSpec.Power"

Nominal volumetric flow rate — Flow rate at reference shaft speed

0.12 m^3/s (default) | positive scalar

Volumetric flow rate through the fan at the reference shaft speed under nominal, typical, or rated operating conditions.

Dependencies

To enable this parameter, set Fan parameterization to Static pressure and flow rate at reference shaft speed.

Programmatic Use

Parameter: flow_rate_nominal

Nominal static pressure gain — Pressure gain at reference shaft speed

5400 Pa (default) | positive scalar

Pressure increase from port A to port B at the reference shaft speed under nominal, typical, or rated operating conditions.

Dependencies

To enable this parameter, set Fan parameterization to Static pressure and flow rate at reference shaft speed.

Programmatic Use

Parameter: pressure_nominal

Nominal efficiency — Efficiency at reference shaft speed

0.40 (default) | positive scalar

Efficiency of converting the shaft power to fluid power at the reference shaft speed under nominal, typical, or rated operating conditions.

Dependencies

To enable this parameter, set:

• Fan parameterization to Static pressure and flow rate at reference shaft speed.

• Shaft power specification to Fan efficiency.

Programmatic Use

Parameter: eta_nominal

Nominal mechanical power — Power at nominal efficiency

1620 W (default) | positive scalar

Mechanical power driving gas flow at the reference shaft speed under nominal, typical, or rated operating conditions.

Dependencies

To enable this parameter, set:

• Fan parameterization to Static pressure and flow rate at reference shaft speed.

• Shaft power specification to Brake power.

Programmatic Use

Parameter: power_nominal

Maximum static pressure gain at zero flow — Maximum pressure at reference shaft speed

6400 Pa (default) | positive scalar

Pressure increase from port A to port B at the reference shaft speed when there is no flow through the fan.

Dependencies

To enable this parameter, set Fan parameterization to Static pressure and flow rate at reference shaft speed.

Programmatic Use

Parameter: pressure_max

Maximum volumetric flow rate at zero pressure — Maximum flow rate at reference shaft speed

0.24 m^3/s (default) | positive scalar

Free-delivery volumetric flow rate at the reference shaft speed and constant pressure.

Dependencies

To enable this parameter, set Fan parameterization to Static pressure and flow rate at reference shaft speed.

Programmatic Use

Parameter: flow_rate_max

Reference shaft speed — Fan curve reference speed

3000 rpm (default) | positive scalar

Reference shaft angular velocity corresponding to the fan characteristic curve data.

Dependencies

To enable this parameter, set Fan parameterization to Static pressure and flow rate at reference shaft speed or 1D tabulated data - static pressure vs. flow rate at reference shaft speed.

Programmatic Use

Parameter: omega_ref_nominal

Parameter: omega_ref_1D

Minimum shaft speed threshold as fraction of reference — Threshold for minimum shaft speed

1e-2 (default) | positive scalar

Threshold for the minimum shaft speed as a fraction of the reference shaft speed. The block uses this value to prevent the shaft speed from becoming zero and causing a division by zero error in the expression for q_ref.

Dependencies

To enable this parameter, set Fan parameterization to Static pressure and flow rate at reference shaft speed or 1D tabulated data - static pressure vs. flow rate at reference shaft speed.

Programmatic Use

Parameter: omega_threshold_factor

Volumetric flow rate vector — Fan curve flow rate vector

[.0278, .0556, .0833, .111, .139, .167] m^3/s (default) | vector

Vector of volumetric flow rate grid points for the 1-D interpolation of the fan characteristic curve. When Shaft power specification is Brake power, the fan data can extend beyond the normal operating region, and these values can be negative.

Dependencies

To enable this parameter, set Fan parameterization to 1D tabulated data - static pressure vs. flow rate at reference shaft speed.

Programmatic Use

Parameter: flow_rate_1D_TLU

Static pressure gain vector — Pressure gain for given volumetric flow rate

[6410, 6375, 6018, 5366, 4501, 3609] Pa (default) | vector

Vector of pressure gain data points. Each element in the vector corresponds to an element in the Volumetric flow rate vector parameter. The pressure gain is the increase in pressure from port A to port B at the reference shaft speed. When Shaft power specification is Brake power, the fan data can extend beyond the normal operating region, and these values can be negative.

Dependencies

To enable this parameter, set Fan parameterization to 1D tabulated data - static pressure vs. flow rate at reference shaft speed.

Programmatic Use

Parameter: pressure_1D_TLU

Efficiency vector — Efficiency for given volumetric flow rate

[.257, .394, .453, .47, .459, .415] (default) | vector

Vector of fan efficiency data points. Each element in the vector corresponds to an element in the Volumetric flow rate vector parameter. The efficiency is the ratio of fluid power to shaft mechanical power at the reference shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 1D tabulated data - static pressure vs. flow rate at reference shaft speed and Shaft power specification to Fan efficiency.

Programmatic Use

Parameter: eta_1D_TLU

Mechanical power vector — Power for parameterization of torque

[693, 900, 1107, 1267, 1363, 1452] W (default) | 1-by-n vector

Vector of shaft mechanical power data points. Each element in the vector corresponds to an element in the Volumetric flow rate vector parameter. The mechanical power is the power that drives the fan at the reference shaft speed. These values can be negative if the fan data extends beyond the normal operating region.

Dependencies

To enable this parameter, set Fan parameterization to 1D tabulated data - static pressure vs. flow rate at reference shaft speed and Shaft power specification to Brake power.

Programmatic Use

Parameter: power_1D_TLU

Reference density — Density associated with fan curve data

1.2 kg/m^3 (default) | positive scalar

Gas density for a given characteristic fan curve.

Dependencies

To enable this parameter, set Fan parameterization to 1D tabulated data - static pressure vs. flow rate at reference shaft speed, 2D tabulated data - static pressure vs. shaft speed and flow rate or 2D tabulated data - flow rate vs. shaft speed and static pressure.

Programmatic Use

Parameter: rho_ref_1D

Parameter: rho_ref_dp

Parameter: rho_ref_q

Shaft speed vector, w — Shaft angular velocity

[2400; 3000; 3600] rpm (default) | vector

Vector of shaft angular velocity grid points for the 2-D interpolation of the fan characteristic curves.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - static pressure vs. shaft speed and flow rate or 2D tabulated data - flow rate vs. shaft speed and static pressure.

Programmatic Use

Parameter: omega_dp_TLU

Parameter: omega_q_TLU

Volumetric flow rate vector, q — Flow rate for parameterization of pressure gain

[.0278, .0556, .0833, .111, .139, .167] m^3/s (default) | 1-by-n vector

Vector of volumetric flow rate grid points for the 2-D interpolation of the fan characteristic curves. When Shaft power specification is Brake power, the fan data can extend beyond the normal operating region, and these values can be negative.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - static pressure vs. shaft speed and flow rate.

Programmatic Use

Parameter: flow_rate_dp_TLU

Static pressure gain table, dp(w,q) — Pressure for parameterization of pressure

[4111, 4010, 3551, 2881, 2167, 1453; 6410, 6375, 6018, 5366, 4501, 3609; 9217, 9285, 9022, 8428, 7552, 6482] Pa (default) | M-by-N matrix

M-by-N matrix of pressure gain data points for the 2-D interpolation of the pressure gain. The pressure gain is the increase in pressure from port A to port B. When Shaft power specification is Brake power, the fan data can extend beyond the normal operating region, and these values can be negative. M and N are the sizes of the corresponding vectors:

• M is the number of elements in the Shaft speed vector, w parameter. The elements corresponding to zero flow rate must be in strictly ascending order.

• N is the number of elements in the Volumetric flow rate vector, q parameter.

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Static pressure gain table, dp(w,q), Efficiency table, eta(w,q), and Mechanical power table, W(w,q) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - static pressure vs. shaft speed and flow rate.

Programmatic Use

Parameter: pressure_dp_TLU

Efficiency table, eta(w,q) — Efficiency for parameterization of torque

[.3, .434, .468, .459, .4, .3; .257, .394, .453, .47, .459, .415; .225, .359, .434, .461, .47, .459] 1 (default) | M-by-N matrix

M-by-N matrix of efficiency data points for the 2-D interpolation of torque. The efficiency is the ratio of fluid power to shaft mechanical power. M and N are the sizes of the corresponding vectors:

• M is the number of elements in the Shaft speed vector, w parameter.

• N is the number of elements in the Volumetric flow rate vector, q parameter.

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Static pressure gain table, dp(w,q), Efficiency table, eta(w,q), and Mechanical power table, W(w,q) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - static pressure vs. shaft speed and flow rate and Shaft power specification to Fan efficiency.

Programmatic Use

Parameter: eta_dp_TLU

Mechanical power table, W(w,q) — Mechanical power for parameterization of torque

[381, 514, 632, 697, 753, 809; 693, 900, 1107, 1267, 1363, 1452; 1139, 1438, 1732, 2029, 2233, 2358] W (default) | M-by-N matrix

M-by-N table of mechanical power data points for the 2-D interpolation of torque. These values can be negative if the fan data extends beyond the normal operating region. The mechanical power is the power that drives the fan. M and N are the sizes of the corresponding vectors:

• M is the number of elements in the Shaft speed vector, w parameter. The elements corresponding to zero flow rate must be in strictly ascending order.

• N is the number of elements in the Volumetric flow rate vector, q parameter.

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Static pressure gain table, dp(w,q), Efficiency table, eta(w,q), and Mechanical power table, W(w,q) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - static pressure vs. shaft speed and flow rate and Shaft power specification to Brake power.

Programmatic Use

Parameter: power_dp_TLU

Static pressure gain vector, dp — Pressure for parameterization of flow rate

[31, 62, 93, 124] Pa (default) | 1-by-N vector

Vector of pressure gain grid points for the 2-D interpolation of the fan characteristic curves. When Shaft power specification is Brake power, the fan data can extend beyond the normal operating region, and these values can be negative.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - flow rate vs. shaft speed and static pressure.

Programmatic Use

Parameter: pressure_q_TLU

Volumetric flow rate table, q(w,dp) — Flow rate for parameterization of flow rate

[.802, .759, .703, .611; .936, .902, .862, .81; 1.056, 1.027, .994, .956] m^3/s (default) | M-by-N matrix

M-by-N matrix of volumetric flow rate data points for the 2-D interpolation of volumetric flow rate. When Shaft power specification is Brake power, the fan data can extend beyond the normal operating region, and these values can be negative. M and N are the sizes of the corresponding vectors:

• M is the number of elements in the Shaft speed vector, w parameter. The elements corresponding to zero flow rate must be in strictly ascending order.

• N is the number of elements in the Static pressure gain vector, dp parameter.

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Volumetric flow rate table, q(w,dp), Efficiency table, eta(w,dp), and Mechanical power table, W(w,dp) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - flow rate vs. shaft speed and static pressure.

Programmatic Use

Parameter: flow_rate_q_TLU

Efficiency table, eta(w,dp) — Efficiency for parameterization of torque

[.088, .162, .22, .261; .068, .128, .18, .222; .055, .105, .148, .188] (default) | M-by-N matrix

M-by-N matrix of efficiency data points for the 2-D interpolation of torque. The efficiency is the ratio of fluid power to shaft mechanical power. M and N are the sizes of the corresponding vectors:

• M is the number of elements in the Shaft speed vector, w parameter.

• N is the number of elements in the Static pressure gain vector, dp parameter.

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numeric values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Volumetric flow rate table, q(w,dp), Efficiency table, eta(w,dp), and Mechanical power table, W(w,dp) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - flow rate vs. shaft speed and static pressure and Shaft power specification to Fan efficiency.

Programmatic Use

Parameter: eta_q_TLU

Mechanical power table, W(w,dp) — Mechanical power for parameterization of torque

[283, 290, 297, 290; 427, 437, 445, 452; 595, 606, 625, 631] W (default) | M-by-N matrix

M-by-N matrix of mechanical power data points for the 2-D interpolation of torque. These values can be negative if the fan data extends beyond the normal operating region. The mechanical power is the power that drives the fan. M and N are the sizes of the corresponding vectors:

• M is the number of elements in the Shaft speed vector, w parameter. The elements corresponding to zero flow rate must be in strictly ascending order.

• N is the number of elements in the Static pressure gain vector, dp parameter.

If your table has unknown data points, use NaN in place of these values. The block fills in the NaN elements by extrapolating based on the average slope of the fan curves. Do not use artificial numerical values because these values distort fan behavior when operating in that region. When using unknown data:

• The NaN elements in the table must be contiguous.

• The positions of the NaN elements in the Volumetric flow rate table, q(w,dp), Efficiency table, eta(w,dp), and Mechanical power table, W(w,dp) parameters must match each other.

• NaN elements must be located in the upper-right portion of the table, which corresponds to the highest volumetric flow rate and lowest shaft speed.

Dependencies

To enable this parameter, set Fan parameterization to 2D tabulated data - flow rate vs. shaft speed and static pressure and Shaft power specification to Brake power.

Programmatic Use

Parameter: power_q_TLU

Fan diameter scale factor — Model-to-reference scale factor

1 (default) | positive scalar

Geometric scale factor to increase or decrease the size of the simulated fan from the given fan parameterization. The scaling may not be accurate for scale factors much larger or much smaller than 1.

Programmatic Use

Parameter: diameter_ratio

Mechanical orientation — Rotational orientation

Positive angular velocity of port R relative to port C corresponds to normal fan operation (default) | Negative angular velocity of port R relative to port C corresponds to normal fan operation

Normal operating shaft direction. By default, flow and pressure gain are from port A to port B.

Programmatic Use

Parameter:	mech_orientation
Values:	"fluids.gas.turbomachinery.enum.FanMechanicalOrientation.Positive" | "fluids.gas.turbomachinery.enum.FanMechanicalOrientation.Negative"

Inlet flow area (port A) — Port A area

0.01 m^2 (default) | positive scalar

Cross-sectional area of the gas flow at the fan inlet.

Programmatic Use

Parameter: area_A

Outlet flow area (port B) — Port B area

0.01 m^2 (default) | positive scalar

Cross-sectional area of the gas flow at the fan outlet.

Programmatic Use

Parameter: area_B

Thermal Effects

Model losses as heat transfer into fluid — Option to model heat transfer into the fluid

off (default) | on

Option to model heat transfer into the fluid. If you clear this parameter, losses from the conversion from mechanical power to fluid power dissipate to the environment. If you select this parameter, the block models these losses as heat transferred into the fluid.

Programmatic Use

Parameter:	model_losses_into_fluid
Values:	"true" | "false"

Gas volume — Gas volume in fan

0.01 m^3 (default) | positive scalar

Volume of the gas in the fan.

Dependencies

To enable this parameter, select Model losses as heat transfer into fluid.

Programmatic Use

Parameter: volume

Initial temperature — Temperature at start of simulation

293.15 K (default) | positive scalar

Temperature in the fluid volume at the start of simulation.

Dependencies

To enable this parameter, select Model losses as heat transfer into fluid.

Programmatic Use

Parameter: T_init

Initial temperature priority — Temperature parameter priority

High (default) | Low | None

Priority that the solver assigns to the Initial temperature parameter when initializing the block.

Set this parameter to High to define your initial conditions. Set this parameter to Low or None if this initial condition conflicts with the initial conditions of another block.

Dependencies

To enable this parameter, select Model losses as heat transfer into fluid.

Programmatic Use

Parameter:	T_init_priority
Values:	"foundation.enum.Priority.High" | "foundation.enum.Priority.Low" | "foundation.enum.Priority.None"

Nominal pressure — Pressure at nominal operating conditions

0.101325 MPa (default) | positive scalar

Pressure in the fluid volume at nominal operating conditions.

Dependencies

To enable this parameter, select Model losses as heat transfer into fluid.

Programmatic Use

Parameter: p_nominal

Nominal temperature — Temperature at nominal operating conditions

293.15 K (default) | positive scalar

Temperature in the fluid volume at nominal operating conditions.

Dependencies

To enable this parameter, select Model losses as heat transfer into fluid.

Programmatic Use

Parameter: T_nominal

Enable thermal port — Option to model thermal port

off (default) | on

Option to model the thermal port associated with the fluid volume.

Dependencies

To enable this parameter, select Model losses as heat transfer into fluid.

Programmatic Use

Parameter:	enable_thermal_port
Values:	"true" | "false"

Plots

Fan characteristics — Generate fan characteristics plot

button

Use the Plot button to generate the fan characteristics plot.

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

Version History

Introduced in R2018b

R2026a: Model heat dissipation

You can now model heat transfer into the fluid by selecting Model losses as heat transfer into fluid. Select Enable thermal port to model the thermal port associated with the internal fluid volume.

R2023a: Expose threshold for low shaft speed

Use the Minimum shaft speed threshold as fraction of reference parameter to control the minimum shaft speed threshold as a fraction of the reference shaft speed. The Minimum shaft speed threshold as fraction of reference parameter is available in the block when the Fan parameterization parameter is Static pressure and flow rate at reference shaft speed or 1D tabulated data – static pressure vs flow rate at reference shaft speed.

R2022b: Extend performance beyond normal operating conditions

Both the 1-D and 2-D parameterizations now allow negative values. When simulation is outside the range of the provided table, block extrapolates the pressure based on the average slope of the fan curves.

You can now use NaN elements where data is unavailable. These 2-D tabulated fan parameters support contiguous NaN elements in the upper-right portion of the table:

• Static pressure gain table, dp(w,q)

• Efficiency table, eta(w,q)

• Mechanical power table, W(w,q)

• Volumetric flow rate table, q(w,dp)

• Efficiency table, eta(w,dp)

• Mechanical power table, W(w,dp)

For each block, if the shaft rotates opposite to the specified mechanical orientation, the pressure difference across the block drops to zero and the results may not be accurate.

R2021b: 2-D Tabulated Data Parameterization: Flow Rate as a Function of Shaft Speed and Pressure Ratio

In R2021b, the block no longer supports the 2-D Tabulated Data Parameterization: Flow Rate as a Function of Shaft Speed and Pressure Ratio parameterization. In R2021b and later, if you open models created in a prior release that include the Fan (G) block, Simscape™ Fluids™ replaces the block with the Fan (MA) - Legacy block. This block supports the 2-D Tabulated Data Parameterization: Flow Rate as a Function of Shaft Speed and Pressure Ratio setting.

You can preserve the functionality of a model using this parameterization by setting Fan parameterization to 2D tabulated data - flow rate vs. shaft speed and static pressure and converting the ratios to absolute values. Prior to R2021b, this setting was called 2D tabulated data - flow rate and total efficiency vs. angular speed and static pressure. An example script that performs this conversion takes in the legacy parameters omega_DpMax_TLU, DpMax_TLU, omega_flow_TLU, Dp_DpMax_TLU, flow_rate_TLU, and eta_flow_TLU and returns the converted parameters omega_g_TLU, pressure_g_TLU, pressure_g_TLU, and eta_g_TLU:

% Shaft speed vector for maximum pressure rise vector 
omega_DpMax_TLU = [1800, 2400, 3000]; 

% Maximum pressure rise vector
DpMax_TLU       = [400, 1200, 2000]; 

% Shaft speed vector, omega 
omega_flow_TLU  = [1800, 2400, 3000]; 

% Static pressure rise ratio vector, Dp/DpMax 
Dp_DpMax_TLU    = linspace(0, 1, 4); 

% Flow rate table, q(omega,Dp/DpMax) 
flow_rate_TLU   = [ 
    0.33    0.26    0.18    0.07 
    1.20    0.91    0.64    0.26 
    1.84    1.61    1.13    0.46]; 

% Total efficiency table, Eta(omega,Dp/DpMax) 
eta_flow_TLU    = [ 
    0.22    0.25    0.27    0.28 
    0.48    0.52    0.55    0.53 
    0.42    0.45    0.49    0.44]; 

% Create interpolants of the tables 
DpMax_TLU_interp = griddedInterpolant(omega_DpMax_TLU, DpMax_TLU, ... 
    'linear', 'linear'); 

flow_rate_TLU_interp = griddedInterpolant({omega_flow_TLU, Dp_DpMax_TLU}, flow_rate_TLU, ... 
    'linear', 'linear'); 

eta_flow_TLU_interp = griddedInterpolant({omega_flow_TLU, Dp_DpMax_TLU}, eta_flow_TLU, ... 
    'linear', 'nearest'); 

% Maximum pressure rise 
DpMax = DpMax_TLU_interp(max(omega_flow_TLU, omega_DpMax_TLU(1)));  

% Shaft speed vector, w 
omega_q_TLU = omega_flow_TLU; 

% Static pressure gain vector, Dp 
pressure_q_TLU = unique(DpMax(:)*Dp_DpMax_TLU(:)'); 

% Interpolation query points as full grid arrays 
omega_grid = omega_q_TLU(:)*ones(1, length(pressure_q_TLU)); 

Dp_DpMax_grid = pressure_q_TLU(:)' ./ DpMax(:); 

% Volumetric flow rate table, q(w,Dp) 
flow_rate_q_TLU = flow_rate_TLU_interp(omega_grid, Dp_DpMax_grid); 

flow_rate_q_TLU = max(flow_rate_q_TLU, 1e-4*flow_rate_TLU(1,1)); % keep it > 0 

% Efficiency table, eta(w,Dp) 
eta_q_TLU = eta_flow_TLU_interp(omega_grid, Dp_DpMax_grid);