*2.2. Experimental Materials*

This paper focuses on the experimental study of copper foam fin radiators with 10 PPI and 20 PPI (as shown in Figure 1). The experimental components used the following dimensions: length 75 mm, width 45 mm and height 17 mm of copper foam radiator, with a base material thickness of 3 mm. The copper foam was cut to the required size using a cutting machine, cleaned with alcohol to remove oil and dust from the surface and then welded to the substrate. The porosity of the copper foam was 96% and the pore density was 10 PPI and 20 PPI, respectively, while the porosity of the aluminum foam was 96% and the pore density was 10 PPI (as shown in Figure 1). The physical properties are shown in Table 1.

**Figure 1.** Copper foam and aluminum foam. (**a**) Copper foam of 10 PPI. (**b**) Copper foam of 20 PPI. (**c**) Aluminum foam of 10 PPI.


**Table 1.** Physical properties of copper foam and aluminum foam.

This paper investigates a copper foam fin radiator at 100 W heating power. The water flow rate was from 10 to 60 L/h and the fins were aligned at 90 degrees to the direction of the water flow. The purpose of this arrangement is to increase the contact surface. The materials filled for the experiments had a pore density of 10 PPI copper metal foam, 10 PPI aluminum metal foam and 20 PPI copper metal foam, as shown in Table 2. The model diagram of the electronic heat sink is shown in Figure 2.


**Table 2.** Type of material used in the experiment.

**Figure 2.** Model diagram of electronic radiator.

## *2.3. Experimental Setup*

The setup contains instruments such as a miniature water pump, an electronic pressure regulator, a paperless recorder, an electrical parameter measuring instrument, a differential pressure transmitter, a constant temperature water bath and a rotameter. A flow chart of the apparatus is shown in Figure 3.

**Figure 3.** Schematic diagram of experimental process. -<sup>1</sup> Data collector -2 Differential pressure transmitter -<sup>3</sup> Regulator -<sup>4</sup> Electrical parameter measuring instruments -<sup>5</sup> Thermostat bath -6 Miniature water pumps -7 Glass rotameter.

The specific parameters of the main instruments and equipment required in the experiment are as follows: armored thermocouples; miniature water pump, Degree New Weicheng Technology Co., Zhuhai, China; silicon-controlled electronic voltage regulator, Shanghai Steadyford Electric Co., Shanghai, China; paperless recorder, Yokogawa Corporation, Japan; electric parameter measuring instrument, Hangzhou Yuanfang Photoelectric Information Co., Hangzhou, China; differential pressure transmitter, Foshan Yizhong Sensing Instrument Co., Foshan, China; constant temperature water bath, Nanjing Xian'ou

Instrument Manufacturing Co., Nanjing, China; glass rotor flowmeter, Leerda Instruments Co., Portland, OR, USA.

The length of the electronic heat sink was 75 mm and the cross-sectional area was 45 mm × 20 mm. The metal foam of different pore densities were filled into the electronic heat sink. The experimental process is as follows: Water with a constant temperature (20 ◦C) is fed into the test section through a rotameter. In the test section and the fins (as shown in Figure 4), the heating plate transfers its own heat to the electronic heat sink through thermal conduction and then exchanges heat with the water. Finally, the heat is discharged from the outlet with the flow of water.

**Figure 4.** Test section renderings and the five fins. (**a**) Test section renderings. (**b**) Physical object of five fins.
