耦合蒸气冷却屏的真空多层绝热结构对液氢储罐自增压过程的影响机制研究

Based on MATLAB program, a transient simulation model considering the vacuum multi-layer insulation, the vapor-cooled shield and the internal fluid domain of liquid hydrogen storage tank is constructed, which can be used to simulate the state change of the storage tank during the full cycle. The dimensionless vapor consumption factor η_c, dormancy extension factor η_s and unit factor η are introduced. η_c represents the vapor consumption of vapor-cooled shield during the full cycle of storage, η_s represents the extension of the dormancy period with vapor-cooled shield opened relative to that with vapor-cooled shield closed, and η is the ratio of η_s to η_c, representing the ability of vapor-cooled shield in shielding heat leakage. The effects of the dimensionless position of vapor-cooled shield, η_c, vapor flow rate and start-up time on η_s and η are investigated. The results show that the optimal position of vapor-cooled shield that maximizes η_s is 0.622 when the starting-up time of vapor-cooled shield is constant. Decreasing η_c helps to increase η. When the position of vapor-cooled shield is 0.622, and η_c decreases from 0.0640 to 0.0128, η increases by 34.7%. However, when the setting of the cooling screen deviates further from the optimal position, decreasing makes the increase smaller. When η_c and the duration time of vapor-cooled shield are fixed, η_s firstly increases then decreases with the delay of the start-up time. When the position of vapor-cooled shield is 0.622, the starting-up time that maximizes η_s is 23.26 d.