By dividing an extraction zone into a finite number of segments, an analysis for each segment is based upon a direct application of the duct branch with uniting flow.

• 方法的要点是利用风道支管流量和压损计算的半径验方法，将抽汽流道分成有限个弧段，视每一弧段为一混合流支管，形成计算模型。