旋进型旋涡流量计是一种新型流量计。被称为70年代的理想的流量计之一。但其内部机理尚待弄清楚。 本文利用高速摄影研究了流体在此流量计中的运动规律,建立了一个较完整、较精确、较具体的物理模型。 本文针对此物理模型进行了理论分析。获得了此流量计的两个基本公式。其中一个公式揭露了旋涡强度同各几何参数和运动参数间的关系,另一个公式表达了涡核的进动规律。 Precession vortex flowmeter is a new type of flowmeter. Called one of the ideal flow meters of the 70s. But its internal mechanism needs to be clarified. In this paper, high-speed photography was used to study the movement of fluid in this flowmeter, and a more complete, accurate and specific physical model was established. This article has carried on the theoretical analysis to this physical model. Obtained two basic formulas of this flowmeter. One of the formulas reveals the relationship between the vortex intensity and each geometric parameter and motion parameter, and the other formula expresses the precession law of the vortex core.