Optimal Design Of Energy Converters Of Dynamic Radioisotope Piezo-Thermoelectric Generator

Radioisotope power systems(RPS)have been playing a significant part in the power supply of deep space/sea exploration,biomedicine,electronics and military defense due to its strong reliability,high power density and long lifetime.During the past half century,RPS with dynamic thermal-to-electric energy conversion was highly concentrated by the academy and industry since the ultrahigh power conversion efficiency and approximate to the ideal Carnot efficiency resulting from Stirling heat engine,turbine,piston,etc.However,the above high-speed moving equipment was difficult to lubricate as well as balance the oscillating forces and torques in the practical test.In 2015,the first dynamic radioisotope piezoelectric generator was reported by Li group,this concept integrated the piezoelectric converter into the Brayton cycle system and replaced the turbine as well as realized the internal self-balance in dynamic RPS.In this thesis,based upon the comprehensive understanding and insight into the origin of thermo-electro-mechanical coupling of the radioisotope decay energy as well as the energy trace,a novel high-performance hybrid RPS,dynamic radioisotope piezo-thermoelectric generator,was redesigned and optimized from energy converters.For instance,the basic mechanical-thermal-electric coupling model,the preparation and measurement of the experimental prototype,the multiphysics finite element analysis,etc.The goal of this thesis is to implement dynamic RPS by using flexible piezoelectric converters and annular thermoelectric generators in principle as well as introduce the research achievements obtained in my Master degree period.The follows are the concept:1.Introduction and review of the research progress and focus in the RPS area during the past century from Chapter 1 to Chapter 2.2.Chapter 3 is the optimization and calculation of theoretical system efficiency.3.In Chapter 4,the energy converters were developed and tested from concept,material,module,device,system,and experimental prototype levels.4.Chapter 5 is mainly focused on the multiphysics numerical simulation of energy converters by COMSOL finite element analysis.5.Chapter 6 is the preliminary evaluation and prediction of durable properties of the system in terms of failure analysis and service behaviors.6.The last Chapter is the conclusion and perspective.The “Best Research-RPS Chart” in the recent ten decades was illustrated.In summary,the primary physical properties of dynamic radioisotope piezo-thermoelectric generator were studied by integrating the mechanical-thermal-electric coupling of flexible energy converters and dynamic thermal-to-electric energy conversion.Although these physical models and experiments are proof-of-principle,we believe that some insights and methods presented in this work can be utilized in related radioisotope/fission power systems as well as energy harvesting in liquid thermodynamic fields,and provide promising references and confidences in the way towards space nuclear power systems and high-efficiency hybrid energy conversion areas.