瞬态模型法Transient model method 基本思想：建立管内流体流动的数学模型，在一定边界条件下求解管内流场，然后将计算值与管端的实测值相比较。当实测值与计算值的偏差大于一定范围时，即认为发生了泄漏。Basic idea： establish the mathematical model of fluid flow in the tube, solve the flow field in the tube under certain boundary conditions, and then compare the calculated value with the measured value at the end of the tube. When the deviation between the measured value and the calculated value is larger than a certain range, the leakage is considered to have occurred. 缺点：难度大且误报率高Disadvantages： difficulty and high false alarm rate