Experimental study on thermoelectric characteristics of thermoacoustic power generator heated by high temperature helium loop

BackgroundA gas-cooled micro-reactor combined with a thermoacoustic power generator is expected to become a new type of highly reliable energy source in the 100 kW power range.PurposeThis study aims to investigate the feasibility and thermoelectric performance of a small gas cooled nuclear power system that couples a helium-cooled micro-reactor heat source with a thermoacoustic generator, and explore its potential for high power-density and mobile applications.MethodsThe transient experimental method was carried out. Firstly, the internal heat exchange structure of the hot head of the thermoacoustic power generator suitable for the gas heat source was designed, and the connection mode between the thermoacoustic power generator and the high-temperature helium loop was designed. Secondly, the test bench was built, which was mainly composed of a helium loop and a thermoacoustic power generator. The helium loop provided high-temperature and high-pressure helium, which simulated the process of nuclear fuel fission and heat generation in a nuclear reactor by electrically heating helium, and realized thermoelectric conversion by helium flow in the thermoacoustic power generator. Finally, transient experiments based on a loop pressure of 0.4 MPa were carried out to study the influence of gas temperature, mass flow rate and other parameters on the dynamic thermoelectric characteristics of the nuclear power supply.ResultsThe experimental results show that the output power and thermoelectric conversion efficiency of the thermoacoustic power generator increase with the increase of helium inlet temperature and flow rate, and the maximum output power is 548 W, and the thermoelectric conversion efficiency is 19.8%. Changing the helium temperature and inlet temperature has a great influence on the temperature at the inlet position of the thermoacoustic power generator hot head, while changing the load resistance is more sensitive to the change of the measurement point in the middle part of the thermoacoustic power generator hot head and the outlet position. When adjusting the load resistance and mass flow rate, the system response times are approximately 10 min and 21 min, respectively.ConclusionsThe results of this study verify the feasibility of the nuclear power source technology based on coupling a gas-cooled micro-reactor with a thermoacoustic power generator, providing an experimental foundation for the future engineering application of small, modular, high power density, and long-lifetime nuclear power systems in marine, land, and aerospace applications.