Consider the phase change material (PCM) of Problems 8.47 and 9.57. The PCM is housed in a long, horizontal, and insulated cylindrical enclosure of diameter De = 200 mm, which in turn includes a concentric, heated inner cylinder of diameter Di = 30 mm. Initially, the PCM is entirely solid and at its phase change temperature. The inner cylinder temperature is suddenly raised to Th = 50°C. Assuming the PCM melts to form an expanding concentric liquid region about the heated tube such as the one shown in the schematic, determine how long it takes to melt half of the PCM.
