Patent ID: 10352741

Abstract:
Method and apparatus capable of accurately measuring a flow rate using Gaussian quadrature even under a small number of measurement points are provided. An average for the y-coordinate of values of normal-directional component with respect to the cross-section represented by vz0(x, y) among an estimated flow velocities in a flow passage cross-section is used as Vz0(x), and a weighting function of Gaussian quadrature is set to Vz0(x)L(x), where L(x)=ymax(x)−ymin(x). Further, an average for y of values of normal-directional component with respect to the cross-section of an actual flow velocity represented by vz(x, y) is used as Vz(x), and an integrand is set to Vz(x)/Vz0(x). These values are used to determine an approximate value of a flow rate according to Gaussian quadrature. In addition, a method of virtually offsetting zero-point of the flow velocity distribution to apparently avoid a problem such as reverse flow is provided.