安全閥釋氣模式研究

Abstract

安全閥為壓力控制裝置的一種，被廣泛使用於與高壓流體有關的高壓儲氣槽。有關安全閥安全性能的分析，目前較普遍使用穩態方式來進行分析，未能真實表現安全閥釋氣過程之暫態現象，且設置一穩態量測系統，需要相當大的氣源，對一般小型實驗室而言是相當不實際的作法。本研究提供一簡易實驗量測方法配合相關統御方程式，以得知安全閥在上游壓力處於充壓或釋壓階段所對應之充壓與釋壓段流量特性方程式，此方法有別於一般傳統穩態方法，無須流量計便可在暫態情況下，得出流出儲槽的流體質量流量，進而可得到被測試安全閥之流量特性。配合此兩階段（充壓與釋壓階段）流量特性方程式並結合相關統御方程式，進行暫態數值模擬外界熱源或外界質量流量的加入儲槽對安全閥的安全性能影響，探討相關衍生現象。

Safety valve is one of pressure controlling devices and employed broadly as a part of overpressure protection systems in high pressure reservoirs. Since phenomena of gas discharged from a high pressure reservoir by a safety valve are at transient state, and up to now the phenomena are hardly investigated by numerical or experimental methods. A method combining both experimental and numerical methods is proposed in this study for determining the transient mass flow rate discharged from a high pressure reservoir by a safety valve. As a result, the valve flow characteristics of the safety valve in both processes of pressure built-up and of pressure discharge can be obtained efficiently, and the mass flow rate discharged from the high pressure reservoir by the safety valve can be calculated. Besides, the discharging phenomena of addition of heat flux and extra mass flow rate into the reservoir can also be analyzed.