Research on sailing range of thermal-electric hybrid propulsion underwater glider and comparative sea trial based on energy consumption

Underwater glider is becoming an increasingly important tool for exploring the ocean. As the underwater tasks become more challenging, it puts forward higher requirements for the endurance of electric underwater gliders. This paper proposes an operation principle for the underwater glider jointly driven by the ocean thermal energy and the electrical energy, which has the advantages of both electric underwater glider and thermal underwater glider. Based on the proposed operation principle, a universal energy consumption model and sailing range equation suitable for the electric, thermal and hybrid propulsion underwater gliders are established. Taking the sailing range, sailing range difference and sailing range ratio as the evaluation indexes, the effects of configuration parameters and navigation parameters on the endurance of three underwater gliders are analyzed. The results show that the endurance and endurance advantage of hybrid propulsion underwater glider can be improved with greater volume change rate of phase change material (PCM), heavier energy carrier and smaller average power of the task sensor, and its high performance can also be maintained with a weight ratio of PCM close to the critical value. Meanwhile, it is beneficial to obtaining stronger endurance for the hybrid propulsion glider during its operation by setting larger diving depth as well as smaller gliding angle and volume change of oil within the design range. Finally, the hybrid propulsion prototype and Petrel-II electric underwater glider are deployed to carry out the comparative sea trial, which verifies the correctness of sailing range equation and the availability of prototype. The results show that the hybrid propulsion underwater glider has a better energy consumption economy than the electric underwater glider.