Convective Heat Transfer

Heat transfer by convection

Library:
Simscape / Foundation Library / Thermal / Thermal Elements

Description

The Convective Heat Transfer block represents a heat transfer by convection between two bodies by means of fluid motion. The transfer is governed by the Newton law of cooling:

$Q = k \cdot A \cdot (T_{A} - T_{B}),$

where:

Q is heat flow.
k is convection heat transfer coefficient.
A is surface area.
D is distance between layers (that is, thickness of material).
T_A and T_B are temperatures of the two bodies.

Connections A and B are thermal conserving ports associated with the points between which the heat transfer by convection takes place. The block positive direction is from port A to port B. This means that the heat flow is positive if it flows from A to B.

Variables

To set the priority and initial target values for the block variables prior to simulation, use the Initial Targets section in the block dialog box or Property Inspector. For more information, see Set Priority and Initial Target for Block Variables.

Ports

Conserving

expand all

`A` — Body A
thermal

Thermal conserving port associated with body A.

`B` — Body B
thermal

Thermal conserving port associated with body B.

Parameters

expand all

`Area` — Area of heat transfer
`0.0001 m^2` (default) | positive scalar

Surface area of heat transfer.

`Heat transfer coefficient` — Convection heat transfer coefficient
`20 W/m^2/K` (default) | positive scalar

Convection heat transfer coefficient.

Model Examples

House Heating System

Model a simple house heating system. The model contains a heater, thermostat, and a house structure with four parts: inside air, house walls, windows, and roof.

Open Model

Lithium-Ion Battery Pack with Fault

Simulate a battery pack consisting of multiple series-connected cells in an efficient manner. It also shows how a fault can be introduced into one of the cells to see the impact on battery performance and cell temperatures. For efficiency, identical series-connected cells are not just simply modeled by connecting cell models in series. Instead a single cell is used, and the terminal voltage scaled up by the number of cells. The fault is represented by changing the parameters for the Cell 10 Fault subsystem, reducing both capacity and open-circuit voltage, and increasing the resistance values.

Open Model

Two-Phase Fluid Refrigeration

Models a vapor-compression refrigeration cycle using two-phase fluid components. The compressor drives the R-134a refrigerant through a condenser, an expansion valve, and an evaporator. The hot gas leaving the compressor condenses in the condenser via heat transfer to the environment. The pressure drops as the refrigerant passes through the expansion valve. The drop in pressure lowers the saturation temperature of the refrigerant. This enables it to boil in the evaporator as it absorbs heat from the refrigerator compartment. The refrigerant then returns to the compressor to repeat the cycle. The controller turns the compressor on and off to maintain the refrigerator compartment temperature within a band around the desired temperature.

Convective Heat Transfer