simulation of the jet emanating from the nozzle in the incoming air stream
This study simulated a jet emanating from the nozzle in the incoming air stream. Experiments have established that the incoming flow (wind) is strongly blurs the jet was also found that the most stable currents in the jet appear on its surface by the incoming flow. The experiments were conducted at a ratio of velocity at the exit of nozzle v0 to flow velocity with equal to 3.5, 5, 7, 10,5.
Experienced border curves plotted in relative coordinates, are shown in Fig. 15. It is seen that for -= 10,5, height above the mouth of the jet nozzle is about 18 pipe diameters, ie, D A18.
SA Klyugpnym in 1952, was proposed an empirical formula derived from experimental data above the researchers to determine the conditional lifting height bulk of the pollutant over the mouth of the nozzle. This formula has the form:
Fig. 15. Experienced boundary curves in the conventional coordinates
The theoretical formula for determining the heights of the flow - from the mouth of the nozzle from the axis, bent by the wind jets - have been proposed by several researchers involved in the scattering in the atmosphere of industrial emissions. Among them, we must first mention the formula PI Andreev received on the basis of the geometric composition of velocities leaving the jet and wind. According to this formula:
where a - coefficient of turbulent jet (I-0.08), a - angle between wind direction and horizon. P. Andreev, treating industrial discharges (ie, have high concentrations of toxic gases), took the angle (x = 20 В°. The author, using the formula for calculating ventilation Andreeva flare emissions, suggested a somewhat smaller magnitude and angle, namely : "-10". At the same time and at the design wind speed of 3 m / s was obtained by the following formula:
Pilot studies, and particularly the work of 10. Ivanov, did not confirm the correctness of the principle of geometric composition of velocities: erosion scab so distorts the theoretical scheme of motion of a curved flow that mathematical relations are incorrect.
Not justified by the PA practice and other theoretical formula derived on the basis of the work of Abramovich and having a look.