Thermal contact conductance#

The Thermal contact conductance block describes heat transfer by thermal conduction between two materials in thermal contact.

Wall geometry type

There are two types of geometry in the block: plane and cylindrical.

Heat flow in planar wall (1) :

(1)#\[Q=\frac{(T_{1}-T_{2})}{\frac{b_1}{\lambda_1 \cdot F}+ \frac{b_2}{\lambda_2 \cdot F}+R}\]

where:

\(\lambda_1\) – thermal conductivity of material 1;

\(\lambda_2\) – thermal conductivity of material 2;

F - heat exchange surface area;

\(b_1\) - distance between the input port and the contact point;

\(b_2\) – distance between the contact point and the output port;

R - contact resistance;

\(T_1\) - temperature at the block inlet;

\(T_2\) - temperature at the block outlet.

Heat flow in cylindrical wall (2) :

(2)#\[Q=\frac{(T_{1}-T_{2})}{\frac {ln(\frac{d_н}{d_{вн}})}{\lambda_1\cdot 2\cdot П \cdot L} +\frac {ln(\frac{d_н}{d_{к}})}{\lambda_2\cdot 2\cdot П \cdot L} +R}\]

where:

L - tube length;

\(d_o\) - outer diameter of the tube;

\(d_c\) - diameter at point of contact;

\(d_{int}\) - internal diameter of the tube.

Type of thermal conductivity

«Constant» - the user-defined thermal conductivity in the fields “Thermal conductivity of the material 1” and “Thermal conductivity of the material 2” is used.

«Table of values» - the thermal conductivity obtained by linear interpolation of values entered by the user in “Thermal conductivity curve for the material” and “Temperature curve for the material” fields is used.

«Material» - the thermal conductivity is used according to the selected material in the associated block Materials properties.

The average temperature is used to calculate thermal conductivity using linear interpolation.

For planar wall (3) :

(3)#\[T_{ср}=\frac{T_{1}+T_{2}}{2}\]

where \(T_1\) and \(T_2\) – temperatures at ends of a layer of the same material.

For a cylindrical wall (4) :

(4)#\[T_{ср}=(T_{1}-T_{2}) \cdot (\frac{d_н}{d_н-d_{вн}}-\frac {1}{ln (\frac{d_н}{d_{вн}})})+T_2\]

1. Properties#

Property	Default value	Description	Units of measurement
Wall geometry type: Plane; Cylindrical	Plane	-	-
Surface area, available when selecting `Wall geometry type` - `Plane`	10.0	-	m\(^2\)
Distance between the input port and the contact point, available when selecting `Wall geometry type` - `Plane`	0.02	-	m
Distance between the contact point and the output port, available when selecting `Wall geometry type` - `Plane`	0.02	-	m
Inner diameter, available when selecting `Wall geometry type` - `Cylindrical`	0.02	-	m
Diameter at contact, available when selecting `Wall geometry type` - `Cylindrical`	0.03	-	m
Outer diameter, available when selecting `Wall geometry type` - `Cylindrical`	0.05	-	m
Length, available when selecting `Wall geometry type` - `Cylindrical`	10	-	m
Contact resistance	5.0e-4	-	°C/W
Conductivity type: Constant; Table of values; Material	Constant	-	-
Thermal conductivity of the material 1, available when selecting `Conductivity type` - `Constant`	1.7	-	W/(m \(\cdot\) К)
Thermal conductivity of the material 2, available when selecting `Conductivity type` - `Constant`	25.0	-	W/(m \(\cdot\) К)
Thermal conductivity curve for the material 1, available when selecting `Conductivity type` - `Table of values`	401.9; 391.5; 385.4; 376.9	-	W/(m·К)
Temperature curve for the material 1, available when selecting `Conductivity type` - `Table of values`	26.85; 126.85; 226.85; 326.85	-	°C
Thermal conductivity curve for the material 2, available when selecting `Conductivity type` - `Table of values`	401.9; 391.5; 385.4; 376.9	-	W/(m·°C)
Temperature curve for the material 2, available when selecting `Conductivity type` - `Table of values`	26.85; 126.85; 226.85; 326.85	-	°C
Material 1 property, available when selecting `Conductivity type` - `Material`	-	-	-
Material 2 property, available when selecting `Conductivity type` - `Material`	-	-	-

2. Inputs and outputs#

Parameters	Input/Output	Description	Units of measurement	Port type
Input	Input	-	-	Heatexchange
Output	Output	-	-	Heatexchange

In order to see the connection capabilities of the block, you need to go to page Description of block ports