Specific Dissipation Heat Exchanger (G-G)

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A heat exchanger parameterized based on data on the relative magnitude of heat transfer for systems with two gas flows.

blockType: EngeeFluids.HeatExchangers.SpecificDissipation.GasGas

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/Physical Modeling/Fluids/Heat Exchangers/Gas/Specific Dissipation Heat Exchanger (G-G)

Description

Block Specific Dissipation Heat Exchanger (G-G) simulates a gas-to-gas heat exchanger. The heat carriers are homogeneous in their phase state, and each of them is a gas. The phase transition in the process is excluded, which determines exclusively the contact heat exchange (without latent heat).

heat exchanger g g 1

The heat transfer model

The block’s heat transfer model is based on the concept of the relative magnitude of heat transfer, a measure of the heat transfer rate observed with a one-degree temperature difference between gas 1 and gas 2 at the inlet. Multiplying by the temperature difference at the inlet gives the expected heat transfer rate.

where — the relative value of heat transfer, — gas temperature 1 (lower index ) or Gaza 2 (lower index ) at the entrance. The relative heat transfer value is a tabular function of the mass flow rate entering the heat exchanger through the ports connected to gas 1 and gas 2.:

To account for reverse flows, the tabular data can be expanded for positive and negative flow rates, in which case the input ports can also be considered as output ports. The data is usually obtained by measuring the dependence of the heat transfer rate on the temperature in a real model.:

The heat transfer model, based almost entirely on tabular data, which is usually obtained experimentally, does not require a detailed description of the heat exchanger. It is assumed that the flow pattern of the heat carriers, the mixing condition and the number of strokes of the casing or pipe, if they are related to the simulated heat exchanger, are fully reflected in the tabular data.

For more information about heat transfer calculations, see the section Specific Dissipation Heat Transfer.

Block structure

A block is a composite component built from simpler blocks. Block Specific Dissipation Heat Exchanger Interface (G) simulates the gas flow on side 1 of the heat exchanger. The other block simulates the gas flow on side 2. Block Specific Dissipation Heat Transfer it takes into account the heat exchange between the flows through the wall.

specific dissipation heat exchanger g g

Ports

Conserving

# A1 — gas inlet or outlet 1
gas

Details

Gas inlet or outlet port 1 on the corresponding side of the heat exchanger.

Program usage name

gas_port_a1

# B1 — gas inlet or outlet 1
gas

Details

Gas inlet or outlet port 1 on the corresponding side of the heat exchanger.

Program usage name

gas_port_b1

# A2 — gas inlet or outlet 2
gas

Details

Gas inlet or outlet port 2 on the corresponding side of the heat exchanger.

Program usage name

gas_port_a2

# B2 — gas inlet or outlet 2
gas

Details

Gas inlet or outlet port 2 on the corresponding side of the heat exchanger.

Program usage name

gas_port_b2

Parameters

Heat Transfer

# Gas 1 mass flow rate vector, mdot1 — The mass flow rate of gas is 1 at each break point in the interpolation table for the relative heat transfer value table
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

The mass flow rate of gas is 1 at each break point in the interpolation table for the relative heat transfer value table. The unit interpolates and extrapolates the values of the break points to obtain the relative heat transfer value of the heat exchanger at any mass flow rate.

The mass flow values can be positive, zero, or negative, but they must monotonously increase from left to right. Their number should be equal to the number of columns in the parameter. Specific dissipation table, SD(mdot1, mdot2). If the table contains lines and For example, the vector of gas mass flow values should contain elements.

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`[0.3, 0.5, 0.6, 0.7, 1.0, 1.4, 1.9, 2.3] kg/s`
Program usage name	`mdot1_heat_transfer_vector`
Evaluatable	Yes

# Gas 2 mass flow rate vector, mdot2 — the mass flow rate of gas 2 at each break point in the interpolation table for the relative heat transfer value table
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

The mass flow rate of gas is 2 at each break point in the interpolation table for the relative heat transfer value table. The unit interpolates and extrapolates the values of the break points to obtain a value for the relative heat transfer of the heat exchanger at any mass flow rate.

The mass flow values can be positive, zero, or negative, but they should increase monotonously from left to right. Their number should be equal to the number of columns in the parameter. Specific dissipation table, SD(mdot1, mdot2). If the table contains lines and If there are no columns, then the vector of gas mass flow values should contain elements.

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`[0.3, 0.5, 1.0, 1.3, 1.7, 2.0, 2.6, 3.3] kg/s`
Program usage name	`mdot2_heat_transfer_vector`
Evaluatable	Yes

# Specific dissipation table, SD(mdot1, mdot2) — the relative value of heat transfer at each break point in the interpolation table of the mass flow rates of gas 1 and gas 2
kW/K

Details

The relative value of heat transfer at each break point is shown in the interpolation table of the mass flow rates of gas 1 and gas 2. The unit interpolates and extrapolates the values of the break points to obtain efficiency for any pair of mass flow rates of gas 1 and gas 2.

The values of the relative heat transfer value should not be negative. They should be aligned from top to bottom in the order of increasing mass flow in the channel for gas 1 and from left to right in the order of increasing mass flow in the channel for gas 2. The number of rows should be equal to the size of the parameter. Gas 1 mass flow rate vector, mdot1, and the number of columns corresponds to the size of the parameter Gas 2 mass flow rate vector, mdot2.

If the heat transfer coefficients are specified in the technical data sheet of your heat exchanger, multiply the specified heat transfer coefficients by the surface area to calculate the relative amount of heat transfer.

Units	`kW/K`
Default value	`[0.324 0.3533 0.404 0.4253 0.4333 0.4373 0.4453 0.4533; 0.3813 0.424 0.496 0.5307 0.544 0.5547 0.5693 0.5787; 0.4267 0.4827 0.5813 0.6173 0.6413 0.6573 0.672 0.6827; 0.4613 0.528 0.64 0.6987 0.7267 0.7467 0.7707 0.7853; 0.5533 0.6467 0.8227 0.928 0.9853 1.0187 1.0653 1.0973; 0.58 0.688 0.8853 1.0147 1.08 1.124 1.176 1.2147; 0.624 0.7467 0.992 1.148 1.244 1.304 1.3773 1.4267; 0.656 0.7907 1.0667 1.26 1.376 1.452 1.548 1.612] kW/K`
Program usage name	`specific_dissipation_matrix`
Evaluatable	Yes

# Check if violating maximum specific dissipation — the status of the warning about the relative amount of heat transfer exceeding the minimum flow heat capacity
None | Error

Details

A warning about the relative amount of heat transfer exceeding the minimum flow heat capacity. The flow heat capacity is the product of mass flow and specific heat, and its minimum value is the smallest of the two flows. This minimum determines the relative amount of heat transfer for a heat exchanger with maximum efficiency and cannot be exceeded. For more information, see the description of the block. Specific Dissipation Heat Transfer.

Values	`None` \| `Error`
Default value	`None`
Program usage name	`Q_assert_action`
Evaluatable	Yes

Gas 1

# Mass flow rate vector — mass flow rate at each break point in the interpolation table for pressure drop
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

The mass flow rate at each break point in the interpolation table of differential pressure values. The unit interpolates and extrapolates the values of the break points to obtain a pressure drop value for any mass flow rate.

The mass flow values can be positive, zero, or negative and can cover laminar, transient, and turbulent zones. However, they should monotonously increase from left to right. Their number must match the size of the parameter. Pressure drop vector, with which they are combined to form tabular breakpoints.

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`[0.3, 0.5, 1.0, 1.5, 2.0, 2.5] kg/s`
Program usage name	`mdot_interface_vector_1`
Evaluatable	Yes

# Pressure drop vector — pressure drop at each break point in the mass flow interpolation table
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure drop at each break point in the mass flow interpolation table. The unit interpolates and extrapolates the break points to obtain a pressure drop value for any mass flow rate.

The pressure drop values can be positive, zero, or negative and can cover laminar, transient, and turbulent zones. However, they should monotonously increase from left to right. Their number must match the size of the parameter. Mass flow rate vector, with which they are combined to form tabular breakpoints.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`[0.003, 0.005, 0.01, 0.025, 0.035, 0.05] MPa`
Program usage name	`delta_p_vector_1`
Evaluatable	Yes

Details

The absolute inlet temperature is determined by collecting tabular pressure drop data. The reference temperature and inlet pressure determine the density of the fluid assumed in the tabular data. During the simulation, the ratio of the reference fluid density to the actual one is multiplied by the differential pressure value shown in the table to obtain the actual pressure drop.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_inflow_ref_1`
Evaluatable	Yes

# Reference inflow pressure — the absolute inlet pressure assumed in the tabular data
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The absolute inlet pressure is determined by collecting tabular pressure drop data. The reference temperature and inlet pressure determine the density of the fluid assumed in the tabular data. During the simulation, the ratio of the reference fluid density to the actual one is multiplied by the differential pressure value shown in the table to obtain the actual pressure drop.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.101325 MPa`
Program usage name	`p_inflow_ref_1`
Evaluatable	Yes

# Mass flow rate threshold for flow reversal — upper bound of the numerically smoothed region for mass flow
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

The mass flow rate below which its value is numerically smoothed to avoid discontinuities that lead to simulation errors at zero flow rate. For more information about calculations, see the description of the block. Specific Dissipation Heat Exchanger Interface (G).

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`1.0e-6 kg/s`
Program usage name	`mdot_threshold_1`
Evaluatable	Yes

# Gas 1 volume — volume of liquid in the gas supply channel 1
l | gal | igal | m^3 | cm^3 | ft^3 | in^3 | km^3 | mi^3 | mm^3 | um^3 | yd^3 | N*m/Pa | N*m/bar | lbf*ft/psi | ft*lbf/psi

Details

The volume of liquid in the gas supply channel 1.

Units	`l` \| `gal` \| `igal` \| `m^3` \| `cm^3` \| `ft^3` \| `in^3` \| `km^3` \| `mi^3` \| `mm^3` \| `um^3` \| `yd^3` \| `Nm/Pa` \| `Nm/bar` \| `lbfft/psi` \| `ftlbf/psi`
Default value	`0.01 m^3`
Program usage name	`V_gas_1`
Evaluatable	Yes

# Cross-sectional area at ports A1 and B1 — the cross-sectional area of the flow at the inlet and outlet of the passage channel
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The cross-sectional area of the flow at the inlet and outlet of the gas supply channel 1. The ports in the same channel have the same size.

Units	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`0.01 m^2`
Program usage name	`port_area_1`
Evaluatable	Yes

Gas 2

# Mass flow rate vector — mass flow rate at each break point in the interpolation table for pressure drop
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`[0.3, 0.5, 1.0, 1.5, 2.0, 2.5] kg/s`
Program usage name	`mdot_interface_vector_2`
Evaluatable	Yes

# Pressure drop vector — pressure drop at each break point in the mass flow interpolation table
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure drop at each break point in the mass flow interpolation table. The unit interpolates and extrapolates the break points to obtain a pressure drop value for any mass flow rate.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`[0.003, 0.005, 0.01, 0.025, 0.035, 0.05] MPa`
Program usage name	`delta_p_vector_2`
Evaluatable	Yes

Details

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_inflow_ref_2`
Evaluatable	Yes

# Reference inflow pressure — the absolute inlet pressure assumed in the tabular data
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.101325 MPa`
Program usage name	`p_inflow_ref_2`
Evaluatable	Yes

# Mass flow rate threshold for flow reversal — the upper bound of the numerically smoothed region for mass flow
kg/s | N*s/m | N/(m/s) | lbf/(ft/s) | lbf/(in/s)

Details

The mass flow rate below which its value is numerically smoothed to avoid discontinuities that lead to simulation errors at zero flow. For more information about calculations, see the description of the block. Specific Dissipation Heat Exchanger Interface (G).

Units	`kg/s` \| `N*s/m` \| `N/(m/s)` \| `lbf/(ft/s)` \| `lbf/(in/s)`
Default value	`1.0e-6 kg/s`
Program usage name	`mdot_threshold_2`
Evaluatable	Yes

# Gas 2 volume — volume of liquid in the gas supply channel 2
l | gal | igal | m^3 | cm^3 | ft^3 | in^3 | km^3 | mi^3 | mm^3 | um^3 | yd^3 | N*m/Pa | N*m/bar | lbf*ft/psi | ft*lbf/psi

Details

The volume of liquid in the gas supply channel 2.

Units	`l` \| `gal` \| `igal` \| `m^3` \| `cm^3` \| `ft^3` \| `in^3` \| `km^3` \| `mi^3` \| `mm^3` \| `um^3` \| `yd^3` \| `Nm/Pa` \| `Nm/bar` \| `lbfft/psi` \| `ftlbf/psi`
Default value	`0.01 m^3`
Program usage name	`V_gas_2`
Evaluatable	Yes

# Cross-sectional area at ports A2 and B2 — the cross-sectional area of the flow at the inlet and outlet of the passage channel
m^2 | cm^2 | ft^2 | in^2 | km^2 | mi^2 | mm^2 | um^2 | yd^2

Details

The cross-sectional area of the flow at the inlet and outlet of the gas supply channel is 2. The ports in the same channel have the same size.

Units	`m^2` \| `cm^2` \| `ft^2` \| `in^2` \| `km^2` \| `mi^2` \| `mm^2` \| `um^2` \| `yd^2`
Default value	`0.01 m^2`
Program usage name	`port_area_2`
Evaluatable	Yes

Effects and Initial Conditions

Details

The temperature in the gas supply channel 1 at the beginning of the simulation.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_start_1`
Evaluatable	Yes

# Gas 1 initial pressure — pressure in the gas supply channel 1 at the beginning of the simulation
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure in the gas supply channel is 1 at the beginning of the simulation.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.101325 MPa`
Program usage name	`p_start_1`
Evaluatable	Yes

Details

The temperature in the gas supply channel 2 at the beginning of the simulation.

Units	`K` \| `degC` \| `degF` \| `degR` \| `deltaK` \| `deltadegC` \| `deltadegF` \| `deltadegR`
Default value	`293.15 K`
Program usage name	`T_start_2`
Evaluatable	Yes

# Gas 2 initial pressure — pressure in the gas supply channel 2 at the beginning of the simulation
Pa | GPa | MPa | atm | bar | kPa | ksi | psi | uPa | kbar

Details

The pressure in the gas supply channel 2 at the beginning of the simulation.

Units	`Pa` \| `GPa` \| `MPa` \| `atm` \| `bar` \| `kPa` \| `ksi` \| `psi` \| `uPa` \| `kbar`
Default value	`0.101325 MPa`
Program usage name	`p_start_2`
Evaluatable	Yes