Mixing in Turbulent Free Jets Issuing from Isosceles Triangular Orifices with Different Apex Angles

摘要

This paper reports the results of an experimental investigation on mixing in turbulent free jets issuing from isosceles triangular orifices with apex angles of 10 deg C, 20 deg C and 30 deg C. The results obtained in a contoured nozzle round jet are also presented for comparison. The measurements were made with an x-array hot-wire probe and a pitot-static tube in isothermal, incompressible jets issuing from the orifices into still surrounding air. The Reynolds number, based on the equivalent diameter of the triangular orifices (the same as the diameter of the contoured round nozzle), was on average 1.93 X 10~(5) in all the jets. The results for the mean streamwise centerline velocity decay and jet entrainment suggest that the 10 deg C jet has the highest mixing rate and that the contoured nozzle round jet has the lowest mixing rate among all the jets tested.