Experimental Study of Effects of Thermocline on the Performance of Underwater Glider´s Thermal Engine

The underwater glider´s thermal engine utilizes ocean thermal energy to change the buoyancy of the glider, which enables it to ascend and descend. A phase change material as the working fluid inside the thermal engine tubes is sensitive to the surrounding seawater temperature, whose effects are different with various thermoclines. To obtain the detailed studies of the effects of the thermocline´s depth, upper thickness, lower thickness and intensity on the performance of the thermal engine, a series of experimental investigations were carried out. The experimental results show that the solidification and melting time of the phase change material depend strongly on the thermocline´s thickness and intensity. For the normal work of the thermal engine, there exist the threshold values of the thermocline´s depth and upper thickness.