## 1 Introduction
[21], based on the transient CFD method and dynamic mesh technology, established a transient hydrogen flow model of the check valve, and the effect of different spool head angles on the closing shock was studied to obtain the optimized design value of the spool head angle. Check valve poor opening dynamic characteristics will occur during valve oscillation and thus cause system pressure fluctuations and valve wear damage, but also will happen during low pressure difference operating conditions that make the valve disc difficult to open [22]. This seriously affects the safety and efficiency of the molten salt conveying system and so it is necessary to study the dynamic characteristics optimization method. Check valve opening characteristics usually include three indicators: minimum opening differential pressure, minimum full opening flow rate, and flow characteristics. The existing literature lacks discussions of the optimization of dynamic characteristics of check valves, but relevant papers on the optimization of product strength and flow properties can provide references. [PERSON] et al. [23] optimized the profile line of the valve core variable opening area of the dynamic flow balance valve by using the pressure drop compensation coefficient revising method, which improved the flow control accuracy. [PERSON] et al. [24] optimized the dimensional parameters of the unloader and suction valve based on the optimization proxy model and NSGA-II algorithm, which effectively improved the movement characteristics and the comprehensive working performance of the stepless flow control system. [PERSON] et al. [25] designed a three-dimensional heat sink with a load-bearing capacity based on a topological optimization method for the heat-flow structure problem. [PERSON] et al. [26] proposed an effective method to eliminate cavitation from a throttling orifice plate, based on genetic algorithm and topology optimization, which ultimately reduces the cavitation area and orifice plate mass. There is a lack of research on the opening dynamic characteristics of molten salt swing check valves for concentrating solar power. The molten salt properties and boundary conditions in molten salt transport systems have a large impact on the opening dynamic characteristics of molten salt check valves. At the same time, the limitations of molten salt test conditions make the relevant tests difficult to perform, and so the numerical simulation study of the dynamic characteristics of high-temperature molten salt swing check valve is an important step in the performance testing of check valves. More importantly, the existing research on the dynamic characteristics of valves mainly analyzes the dynamic characteristics of valves under different working parameters or different structural parameters to facilitate the valve design and selection process, but there is a lack of research on how to optimize the dynamic characteristics through structural improvement. In this study, a high-temperature molten salt swing check valve is designed to meet the working requirements of a molten salt swing check valve in high-temperature and high-pressure conditions. The product is designed to possess anti-crystallization properties and overall exhibit reduced leakage. Based on the moment balance of the valve and considering the molten salt density, a transient dynamics model of the valve motion components is established. After this, the three-dimensional passive dynamic mesh and UDF techniques are used to study the opening dynamic characteristics. A method is proposed for optimizing the topology of the valve motion components to improve the opening performance of the check valve, analyze the effect of mass retention rate \(u\) on the topology optimization results, and determine a new valve disc structure that meets the requirements of strength, stiffness and reverses sealing.