Diameter bisection: An effective traverse method in Pitot tube based flow measurement

When measuring the flow rate with Pitot tubes, point velocity measurements are commonly combined with traverse methods such as the equal ring method, loglinear method, and Tchebycheff method. The weighted average of the velocities of each traverse point is computed to represent the average flow velocity of the pipe section. Because these methods only consider the velocity distribution, they often over-complicate the distribution of the traverse points, which are then difficult to pinpoint. This paper proposes a novel traverse method with a Pitot tube, which is based on the diameter bisection principle. In this method, the traverse points are located successively along the pipe radius, at distances 2
^-1
, 2
^-2
, ..., 2
^-n
(n = 1, 2, 3, ...) times the radius from the center of the pipe. Compared to the existing traverse methods, such as the equal ring method, log-linear method, and Tchebycheff method, the diameter bisection method of locating the traverse points is relatively simple. And when the need arises to increase or decrease the number of traverse points, the preceding traverse points and the corresponding velocity data remain unchanged thereby effective. In this paper, under different flow rates, measurements of the velocity are made at the traverse points prescribed by the log-linear method, Tchebycheff method, and diameter bisection method. The results show that, compared to the log-linear method and Tchebycheff method, the diameter bisection method resulted in a smoother trend of errors; and the flow rate correction factors are more stable. Thus, using the bisection principle to locate the traverse points for flow measurement in a non-standardized situation has a certain advantage.