# Transient temperature calculator

In this calculator you can calculate the steady state temperatures of a network. As well as the temperatures as function of time. Follow the steps, and if you are ready press the button calculate and evaluate the results in the graph.

In a lumped capacity model, a thermal system is divided in to

• Heat Capacities
• Thermal Couplings

The heat capacities are called Nodes, and it is assumed that the temperature in one node is uniform. Heat capacities can be:

• Large parts
• Thermally conductive parts
• Multiple parts with good thermal conducion between them
• Parts with "important" temperatures

In the image above, a three node system is shown. Part 1 is in contact with body 2 by a few connection points. Body 2 is in contact with body 3, which is a large and surrounds the other parts.
In the picture to the right, the conductive couplings and radiation couplings identified. Body 1 has a heat source.

Use the calculation tool to calculate the temperatures as function of time.

### Step 1 Input system size

 #nodes 23456 How many nodes does the system contain?(2-6)if you change this, all data will be lost.

### Step 2 Input thermal couplings

 from to type value[W/K] node1node2node3node4node5node6 node1node2node3node4node5node6 Conduction Convection Radiation

 node1 node2 node3 node4 node5 node6 node1 0 0 0 0 0 0 node2 0 0 0 0 0 0 node3 0 0 0 0 0 0 node4 0 0 0 0 0 0 node5 0 0 0 0 0 0 node6 0 0 0 0 0 0

 node1 node2 node3 node4 node5 node6 node1 0 0 0 0 0 0 node2 0 0 0 0 0 0 node3 0 0 0 0 0 0 node4 0 0 0 0 0 0 node5 0 0 0 0 0 0 node6 0 0 0 0 0 0

 node1 node2 node3 node4 node5 node6 node1 0 0 0 0 0 0 node2 0 0 0 0 0 0 node3 0 0 0 0 0 0 node4 0 0 0 0 0 0 node5 0 0 0 0 0 0 node6 0 0 0 0 0 0

### Step 3 Constant temperatures nodes (e.g. heatsinks)

node temperature [K]

 node1 node2 node3 node4 node5 node6 T - - - - - -

### Step 4 Input Heat loads

node Power [W]

 node1 node2 node3 node4 node5 node6 Q 0 0 0 0 0 0

### Step 5 Calculate steady state

Press calculate to evaluate the results

-

-

(drag blocks to rearrange locations)

### Step 6 Input heatcapacities of the nodes ( C=L*B*H*rho*Cp)

node Capacity [J/K]

 node1 node2 node3 node4 node5 node6 node1 0 0 0 0 0 0 node2 0 0 0 0 0 0 node3 0 0 0 0 0 0 node4 0 0 0 0 0 0 node5 0 0 0 0 0 0 node6 0 0 0 0 0 0

### Step 7 Input Initial Temperatures (specifify for all)

node Temperature [K]

 node1 node2 node3 node4 node5 node6 T 0 0 0 0 0 0

### Step 8 Set simulation time

 [s] Current: t_end =NaNs

### Step 9 Calculate Transient Temperature

Xnode1node2node3node4node5node6
0000000
1000000

## References

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