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Simple Heat Exchanger (G)

Simple model of a heat exchanger between a gas network and a general fluid

  • Library:
  • Fluid Network Interfaces / Heat Exchangers

Description

The Simple Heat Exchanger (G) block models the heat transfer and fluid dynamics of a heat exchanger located between a gas network and an external fluid. The model is based on tabulated data relating the operating conditions inside the heat exchanger—the mass flow rate, pressure drop, and specific dissipation factor, a measure of heat exchange effectiveness.

The fluid properties of the gas network do not apply to the external fluid. These are specified for the gas network through a Gas Properties (G) block and for the external fluid through physical signals. Port CP2 provides the isobaric specific heat of the external fluid and port M2 provides its mass flow rate. The rate of heat transfer is computed using the specific dissipation method.

Component Structure

This block is a composite component assembled from simpler components found in the Fundamental Components library. A Specific Dissipation Heat Transfer block captures the heat transfer between the gas networks. A Simple Heat Exchanger Interface (G) block captures the pressure drop and temperature change between the gas inlets.

Component Block Diagram

Ports

Input

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Isobaric specific heat of the controlled fluid.

Entrance mass flow rate of the controlled fluid. Positive values indicate flow into the heat exchanger. Negative values indicate flow out of the heat exchanger.

Conserving

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Opening through which gas 1 can enter and exit the heat exchanger.

Opening through which gas can enter and exit the heat exchanger.

Thermal port associated with the inlet temperature of the external fluid.

Parameters

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Heat Transfer Tab

Array of mass flow rates at the gas inlet. Each value corresponds to a row in the specific dissipation lookup table. Positive values indicate flow into the heat exchanger and negative values indicate flow out of the heat exchanger.

Array of mass flow rates at the inlet for the controlled fluid. Each value corresponds to a row in the specific dissipation lookup table. Positive values indicate flow into the heat exchanger and negative values indicate flow out of the heat exchanger.

Matrix of specific dissipation values corresponding to the specified mass flow rate arrays for the gas and controlled fluid. The block uses the tabulated data to calculate the heat transfer at the simulated operating conditions.

Option to warn if the specific dissipation falls outside the bounds of the specified tabulated data.

Pressure Loss Tab

Array of mass flow rates at which to specify the pressure drop tabulated data.

Array of pressure drops from inlet to outlet corresponding to the tabulated mass flow rate data.

Temperature at which the tabulated pressure-drop data is specified.

Pressure at which the tabulated pressure-drop data is specified.

Mass flow rate below which to initiate a smooth flow reversal to prevent discontinuities in the simulation data.

Volume of gas occupying the heat exchanger at any given time. The initial conditions specified in the Effects and Initial Conditions tab apply to this volume. The volume is constant during simulation.

Flow area at the gas inlets. Inlets A1 and B1 are assumed to be identical in size.

Effects and Initial Conditions Tab

Temperature of the internal volume of gas at the start of simulation.

Pressure of the internal volume of gas at the start of simulation.

Introduced in R2017b

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