基于三维核热耦合方法的吸气式核反应堆瞬态特性研究

Study on Transient Characteristics of Nuclear Ramjet Reactor Based on Three-Dimensional Nuclear Thermal Coupling Method

吸气式反应堆具有大比冲、高功率密度的优良特点,在未来空天推进领域具有广阔的应用前景。该反应堆在正常运行条件下需要完成各类功率快速响应的瞬态工况,并在极短时间内完成启停堆过程,采用传统的数值方法研究其瞬态三维核热耦合特性存在较大的困难。本文基于开源OpenFOAM平台,开发了三维瞬态核热耦合求解程序,提出了新型流固热耦合边界,实现了固体堆芯与流道内部流动传热特性的快速预测,使用点堆模型求解堆芯中子物理特性,通过耦合物理模块与热工模块实现了瞬态过程中气式反应堆堆芯流动传热特性的数值分析。模拟结果表明,吸气式反应堆在功率快速提升的同时,固体材料的温度不会迅速升高,而是平稳上升直至稳态,反应堆在瞬时热功率超过设计基准值的启堆过程中仍然是安全的。

The ramjet reactor has excellent characteristics of large specific impulse and high power density,and has broad application prospects in the field of aerospace propulsion in the future.Under normal operating conditions,the reactor needs to complete various transient operating conditions with rapid power response,and complete the startup and shutdown process in a very short time.The use of traditional numerical methods to study its transient three-dimensional nuclear-thermal coupling characteristics has great difficult.Based on the open source OpenFOAM platform,this paper developed a three-dimensional transient nuclear-thermal coupling solution program,proposed a new fluid-solid coupling boundary,and realized the rapid prediction of the flow and heat transfer characteristics of the solid core and the flow channel.The point kinetic model was employed to solve the core neutron physical properties.Through the coupling of the physical module and the thermal module,realize the numerical analysis of the flow and heat transfer characteristics of the gas reactor core during the transient process.The simulation results show that while the power of the ramjet reactor increases rapidly,the temperature of the solid material will not rise fast,but will rise steadily until it reaches a steady state.The reactor is still safe during the startup process when the instantaneous thermal power exceeds the design benchmark value.