FLOW MEASUREMENT USING SUPERSONIC FLOW METER

摘要

PURPOSE:To obtain a flow value with high precision by obtaining a dynamic viscosity factor based on a relationship between a measured temperature and a dynamic viscosity factor and computing Reynolds number and a flow distribution through combination of data on the tubular diameter of a conduit passage for a fluid and data obtained from a supersonic flow meter. CONSTITUTION:A reception frequency difference DELTAf attributable to a flow velocity u(r) is computed by means of supersonic transmitter/receivers 2A and 2B provided at two points on a conduit wall in such manner that the tubular axis 4 and angle theta of a wave conduction channel 1 having a cross-section shape which allows the formation of a function f(r,Re) of Reynolds number Re and a radius r by a flow velocity distribution. Then nu is calculated based on the already obtained relationship between temperature gamma and dynamic viscosity factor nu and thereafter, Re is obtained based on the relationship of said nu and tubular diameter r0. Following this procedure, the maximum value nmax of flow velocity is obtained based on the relationship between f(r,Re) and Q, r obtained by substituting the afore-mentioned distribution function with Re and DELTAf. The afore- mentioned process is repeated a few times sequentially and the final value of the repeated process values is introduced into the formula (1) of a flow Q as a substitute. In calculating Q, a memory unit and an arithmetic unit provided at the latter stage of a flow meter are used. As a result, it is possible to obtain a flow value with less error under no temperature influence.