RU99112370A - METHOD FOR MEASURING AND MONITORING LIQUID OR GAS FLOW PARAMETERS IN A VESSEL WITH ELASTIC WALLS - Google Patents

Claims (2)

1. A method of measuring and monitoring the parameters of a fluid or gas flow in a vessel with elastic walls, including the excitation of elastic waves in the form of pulses along the flow and against the flow, measuring the time it takes for the pulses to travel the base distance from the emitter to the receiver in two directions: along and against the flow, determining the speed and flow rate by the difference in the times the pulses travel the base distance, characterized in that the ultrasonic pulses excite in the elastic walls of the vessel, while the emitter-receiver pair is Laga on the corresponding wall of the vessel and the flow velocity V is determined from the relationship:
V = 2 (2π) ⁴ ΔtT ^-2 L ⁶ RS ^-1 λ ^-4 , (1)
where S is the distance between the same source and receiver;
Δt is the time difference between two pulses of the base distance along and against the flow;
λ is the elastic wavelength in the pipe wall, which is the pulse carrier;
T = (ρ / E) ^1/2 a - unit of dimension of time;
L = [ρah / (2ρ _o )] ^1/2 - unit of dimension of length;
R = ρ $\genfrac{}{}{0ex}{}{\text{2}}{\text{o}}$ / [3 (1-μ ² ) ρ ² ] - a value that determines the degree of interaction of waves in a liquid and elastic waves in the walls of a vessel, the so-called cylindrical stiffness;
ρ is the density of the wall material;
ρ _o is the density of the liquid or gas;
a is the radius of the vessel;
h is the wall thickness of the vessel;
E - Young's modulus of the material of the walls of the vessel;
μ is the Poisson's ratio of the material of the walls of the vessel.  2. The method according to p. 1, characterized in that for the excitation and reception of the ultrasonic wave, a second pair of emitter-receiver is used, while the emitter and receiver of the second pair are located in the opposite order to the first pair at the same base distance.