## 7.21.3 Postprocessing for Radiators

Reporting the Radiator Pressure Drop

You can use the Surface Integrals panel to report the pressure drop across the radiator, as described in Section  29.5. There are two steps to this procedure:

1.   Create a surface on each side of the radiator zone. Use the Transform Surface panel (as described in Section  27.10) to translate the radiator zone slightly upstream and slightly downstream to create two new surfaces.

2.   In the Surface Integrals panel, report the average Static Pressure just upstream and just downstream of the radiator. You can then calculate the pressure drop across the radiator.

To check this value against the expected value based on Equation  7.21-1, you can use the Surface Integrals panel to report the average normal velocity through the radiator. (If the radiator is not aligned with the , , or axis, you will need to use the Custom Field Function Calculator panel to generate a function for the velocity normal to the radiator.) Once you have the average normal velocity, you can use Equation  7.21-2 to determine the loss coefficient and then Equation  7.21-1 to calculate the expected pressure loss.

Reporting Heat Transfer in the Radiator

To determine the temperature rise across the radiator, follow the procedure outlined above for the pressure drop to generate surfaces upstream and downstream of the radiator. Then use the Surface Integrals panel (as for the pressure drop report) to report the average Static Temperature on each surface. You can then calculate the temperature rise across the radiator.

Graphical Plots

Graphical reports of interest with radiators are as follows:

• Contours or profiles of Static Pressure and Static Temperature.

• XY plots of Static Pressure and Static Temperature vs position.

Chapter  28 explains how to generate graphical displays of data.

 When generating these plots, be sure to turn off the display of node values so that you can see the different values on each side of the radiator. (If you display node values, the cell values on either side of the radiator will be averaged to obtain a node value, and you will not see, for example, the pressure loss across the radiator.)

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