System Design And Performance Analysis Of Thermal-electric Hybrid Power Underwater Glider

Underwater glider is a type of autonomous underwater vehicle(AUV)driven by buoyancy and cruising in the ocean along sawtooth trajectories.Due to remarkable high endurance,long range,low noise and less cost,underwater gliders have a broad application prospect in the marine observation.A new type of underwater glider,Thermal-Electric Hybrid Power Underwater Glider(TEG),is presented in the thesis.TEG integrates the thermal-driven system and electric-driven system,realizing buoyancy-driven by transforming ocean thermal energy into mechanical energy or consuming the electric power from battery.Thermal-driven system reduces the electric power consumption while electric-driven system raises the cycling stability and the environmental adaptability of TEG.To the questions that came from TEG development process,a uniform sailing range formula and a thermal-driven phase transition model were established.The influences of configuration parameters,navigation control parameters and temperature conditions on thermal-driven performance,glider endurance and efficiency were studied.The following contributions have been made:1.The thesis presented an analysis method of configuration parameters,taking sailing range as the evaluation indicator.Based on the energy transfer and transformation process,a uniform sailing range formula was proposed.Based on sailing range formula,constraints of configuration parameters were derived while the relationships between configuration parameters and glider endurance were investigated emphatically,providing guidance for TEG design.2.Based on phase transformation & heat transfer theory and thermal buoyancy driven principle,a thermal-driven phase transition model was established to simulate the TEG thermal cycling process.In the model,driven system pressure was proposed to associate the energy storage process of driven system and the phase transform process of phase change material(PCM),while the effect of temperature and pressure factors on the thermophysical properties of PCM and that of the volume change on cell position were considered.This model reflects the thermal buoyancy driven process accurately and provides a reference for building similar phase transition models.3.For better thermal-driven performance and glider endurance,the optimal navigation control parameter combinations and temperature condition requirements were proposed.Based on thermal-driven phase transition model,the driven process under constant temperature conditions was studied.Moreover,TEG gliding process and thermal cycling process were combined by temperature profile equations and vertical dynamic equations.The influence of navigation control parameters and temperature profile conditions on thermal-driven performance and glider endurancewas analyzed.The work provides guidance for sea trials control and glider performance prediction.4.The first engineering prototype of TEG was developed.A series of tests were carried out to inspect the function realization and operational reliability of TEG prototype,to demonstrate the correctness and validity of theoretical models.The results of a long-range comparative trial show that TEG has a higher energy consumption economy than electric-driven underwater glider “Petrel-II”.