The Leung method proposed by the Design Institute of Emergency Relief Systems (DIERS) is widely used in the design of relief systems involving two-phase flow. However, this method is not always suitable for all the situations. The calculating results may be unacceptably large, especially under high overpressure. To aid selection of appropriate vent sizing methods, a typical vapor system experiment (esterification of methanol-acetic and anhydride) was conducted by the vent sizing unit (VSU) of accelerating rate calorimeter (ARC). Seven different stationary methods were used to calculate the venting size under overpressure of 10%, 20%, 50%, 100% and 200%. Through the systematic comparison of different methods, a conservatism order of stationary methods was summarized as well as the selecting principles for these methods were discussed. Process simulation was also applied to investigate the relationship between reactor temperature/pressure and its relief size, which could be used in the prediction of vent size in vapor system conveniently without complex calculating procedure.

紧急救援系统设计院（DIERS）提出的Leung方法广泛用于涉及两相流的救援系统的设计。然而，这种方法并不总是适用于所有情况。计算结果可能大得无法接受，尤其是在高超压下。为了帮助选择合适的排气尺寸方法，通过加速量热计 (ARC) 的排气尺寸单元 (VSU) 进行了典型的蒸汽系统实验（甲醇-乙酸和酐的酯化）。使用七种不同的固定方法来计算 10%、20%、50%、100% 和 200% 超压下的排气尺寸。通过对不同方法的系统比较，总结了平稳方法的保守顺序，并讨论了这些方法的选择原则。