The Research Of The Performance Of Underwater Thermal Glider Under Weak Or Inverse Temperature Gradient

Underwater glider is a new type of Autonomous Underwater Vehicle (AUV). It's a stealthy robot which has very high sailing and energy efficiency. Thus underwater glider has a bright future in marine research and military field. Underwater thermal glider takes ocean thermal energy as the driving force, and has better endurance compare with other which uses battery power. Phase change material (PCM) which is used as working fluid is contented in a pipe which is an important part of ocean thermal energy propulsion system.The purposes of this paper are to analyses and improve the phase change process of PCM under weak or reverse temperature gradient conditions. Thus research the deign method of underwater thermal glider parameter and optimize the performance of underwater glider in weak or reverse temperature gradient.By using enthalpy method, a phase change process model has been built, discrete the calculation area by outer regions of the node method and discrete equations by control volume method, then solve the model by using TDMA algorithm. This model provides the result of phase change process under weak or reverse temperature gradient conditions.By analyzing the phase change process under weak or reverse temperature gradient conditions, the result that weak or reverse temperature gradient will impede the phase change process is given. And to ensure the working efficiency of the underwater thermal glider, the critical sailing range is introduced. Reprogramming the solving method of the phase change process model, and the critical sailing range is calculated to evaluate the performance of the underwater thermal glider. And the result that weak temperature gradient will enlarge the critical sailing range is given.The hydrodynamic performance of the underwater thermal glider is analyzed and the parameters which influence the hydrodynamic performance are been researched. Take the diameter of the pipe and vertical speed as the research object, to study the phase change performance under different diameter of the pipe and vertical speed. Then optimize these parameters, and the idea of circular energy storage pipe is given, and the result that underwater thermal glider would have a considerable efficiency when sailing angle is between 25°and 45°is given.To avoid the disadvantage of field experiment, a model experiment device is introduced. The theory of the testing device is illuminated and the detail design of this device is taken. Based on the design, the testing device is been built, and a simulation which consider two kind of working condition is done by using Fluent. Finally, the performance of the testing device is been provide and an optimize method of thermocline simulation is given.