On the Experimental Investigations of Float-Area-Type Flow Meters : Turbulent Region

Abstract

From the theoretical results reported before, the flow rate characteristics of float-area-type flow meters were formulated as a function of four dimensionless parameters, when the flow in the clearance between the tapered tube and the float was laminar. In this study, the flow rate characteristics for turbulent region were experimentally examined. It was pointed out that the flow rate characteristics were greatly influenced by the separation of flow at minimum clearance. As a result, widely used floats having usual shapes were classified into two types, i.e., floats with large length of the part of the maximum diameter and those with small length of that part. It was experimentally shown that the number of dimensionless parameters influencing the flow rate characteristics were reduced to three when large-length floats were employed and to two when small-length floats were employed, respectively. Moreover, when small-length floats were employed, a semi-empirical formula to obtain the general flow rate characteristics of this kind of flow meter was proposed.