Periodic solid CO2 deposition and melting phenomena happen during releasing high pressure CO2 through a safety valve from CO2 refrigeration system into atmosphere, and a longer duration of the deposition and a shorter...Periodic solid CO2 deposition and melting phenomena happen during releasing high pressure CO2 through a safety valve from CO2 refrigeration system into atmosphere, and a longer duration of the deposition and a shorter duration of melting are advantageous for the system safety. In order to understand the characteristics of CO2 melting during releasing through the safety valve and achieve a shorter duration of melting, a transient simulation model was established. The validation of the model was done by comparison of the calculation results and experimental data. Calculation with the model showed that:(1)the downstream pressure of the safety valve increased at first and then decreased after a total blockage happened;(2)the upstream vapor quality of safety valve had a small effect on the melting time, but greatly increased the maximum downstream pressure;(3)the melting process became longer and the maximum downstream pressure increased with the increase of the length of blockage;(4) the melting time increased and the maximum downstream pressure decreased with the increase of the length of blockage and the increase of the radius of the downstream tube.展开更多
文摘Periodic solid CO2 deposition and melting phenomena happen during releasing high pressure CO2 through a safety valve from CO2 refrigeration system into atmosphere, and a longer duration of the deposition and a shorter duration of melting are advantageous for the system safety. In order to understand the characteristics of CO2 melting during releasing through the safety valve and achieve a shorter duration of melting, a transient simulation model was established. The validation of the model was done by comparison of the calculation results and experimental data. Calculation with the model showed that:(1)the downstream pressure of the safety valve increased at first and then decreased after a total blockage happened;(2)the upstream vapor quality of safety valve had a small effect on the melting time, but greatly increased the maximum downstream pressure;(3)the melting process became longer and the maximum downstream pressure increased with the increase of the length of blockage;(4) the melting time increased and the maximum downstream pressure decreased with the increase of the length of blockage and the increase of the radius of the downstream tube.