Performance analysis of acceleration effect on paraffin melting in finned copper foam
Phase change material (PCM) has great potential in thermal control of aircraft electronic components because of their excellent latent heat capacity. In the current work, a finned copper foam phase change energy storage unit (PCESU) was fabricated using n-eicosane, 97.2% porosity copper foam and 0.8 mm fins. The effects of four different heating power i.e. 40 W, 45 W, 50 W, 55 W corresponding to heat flux of 0.4 W/cm2, 0.45 W/cm2, 0.5 W/cm2, 0.55 W/cm2 at four different centrifugal acceleration magnitudes, i.e. 0 g, 5 g, 9 g, 13 g with three different acceleration directions on the thermal performance of PCESU were experimentally studied in a systematic manner. Experimental results indicated that: (1) the acceleration direction has a significant effect on the thermal performance of PCESU which can be improved for the cases of vertical and opposite direction, whereas restrained for the case of same direction. Under acceleration condition, the average melting time for the cases of opposite and same direction are 15.19% and 37.10% longer than that for the case of same direction, respectively. The temperature difference of PCESU while the melting is completed is 95.12% higher than that for the case of vertical direction on average. (2) the effect of acceleration magnitude on the heat transfer performance can be determined significantly when the acceleration direction is applied. The melting time decreases with the increase of the acceleration magnitude along vertical direction and increases along the same direction. The temperature difference decreases with the increase of the acceleration magnitude along vertical direction, whereas increases along opposite or same direction. Moreover, the melting time and temperature difference for acceleration magnitude changing from 0 g to 5 g have an obvious larger change rate than that from 5 g to 9 g and 9 g to13 g. (3) the melting time is negatively correlated to the heating power, whereas the temperature difference is positively correlated to the heating power. The proposed two-dimensional (2D) simplified model can be helpful to reveal the physical mechanism of the thermal performance of PCESU.