Experiment study on oupling characteristics of thermo-acoustic power generator heated by heat pipe

[Objective] A highly reliable energy-dense power source is the critical core component of the facilities involved in space and ocean exploration. The heat pipe reactor is equipped with a compact solid-state core, which provides benefits such as high reliability, passive heat transfer, and long life, rendering it the ideal solution for the current multipurpose power supply. However, the technical feasibility, reliability, and performance of the alkali metal high-temperature heat pipe, which is the critical component of the heat pipe reactor, remains to be verified and tested. Furthermore, the integrated heat pipes and thermoelectric converter technology need to be validated. In addition, the coupled operating characteristics of heat pipes and thermoelectric converters under high-temperature operating conditions is an important issue that remains to be addressed, both theoretically and experimentally. The principle design of the heat pipe nuclear reactor power supply requires efficient support based on a sufficient amount of experimental data. This study verifies the principle feasibility of the heat pipe nuclear reactor used as a power supply. The operating state features of the alkali metal high-temperature heat pipes and thermo-acoustic power generators under startup and steady states are studied experimentally. [Methods] This paper studies the coupled operating characteristics of sodium heat pipes and thermo-acoustic power generators experimentally. A multihole stainless steel cube assembled with ten electric heating elements and four sodium heat pipes is used to simulate the heat pipe nuclear reactor. A specially designed thermo-acoustic power generator is fitted with two symmetrical generator units and used as the thermoelectric converter. Stimulate and activate the thermo-acoustic power generator while the heat pipes are in fully startup state is the critical operation of thermo-acoustic power generator coupling sodium heat pipe system startup and stable running. [Results] The key technology of sodium heat pipes and thermo-acoustic power generator-integrated system startup method was obtained in this study. The sodium heat pipe was of prominent thermal response, and the temperature buffer could effectively improve the reliability of the thermoelectric conversion system. The coupling characteristics featured by the temperature field evolution of sodium heat pipes and thermoelectric converters were obtained at steady states. The thermoelectric conversion efficiency of the system and the output power of the thermo-acoustic power generator increased as the heat pipe operating temperature rised. In the long-time operation test, with a system heating power of 1900W, the thermo-acoustic power generator output power and thermoelectric conversion efficiency were 360 W and 19. 00%, respectively. In the limit test of the operating temperature, with a heating power of 2 300 W, the thermo-acoustic power generator output power and thermoelectric conversion efficiency were 463 W and 20.13%, respectively. [Conclusions] The integrated technique of high-temperature sodium heat pipes and thermo-acoustic-electric energy converter effectively simulates the processes of heat transfer and thermoelectric conversion of the thermoelectric conversion system based on a heat pipe reactor. The coupling characteristics of heat pipes and thermo-acoustic power generators are obtained. This study verified the energy conversion principle feasibility for a heat pipe reactor coupled with a thermo-acoustic power generator. The results of this study can provide support for the prototype design of a nuclear power facility based on a heat pipe reactor. © 2023 Press of Tsinghua University. All rights reserved.