Experimental investigation of twin and triple elliptic free jets with various nozzle orientations
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Date
2020
Authors
Morris, Ella
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Abstract
The effects of nozzle orientation on the mixing and turbulent characteristics of elliptical free triple and twin jets were studied experimentally. The experiments were conducted using modified contoured nozzles with a sharp linear contraction. The centers of the nozzle pair had a separation ratio of s/d = 5.5 for twin jets and s/d = 4.1 for triple jets. For the twin-jet system, two nozzle configurations were tested, twin nozzles oriented along the minor plane (Twin_Minor) and twin nozzles oriented along the major plane (Twin_Major) and the results were compared with single jet. For the triple-jets system, three nozzle configurations were tested. The first configuration had each nozzle oriented along the minor plane (3_Minor), the next had two nozzles oriented along the minor plane and one along the major plane (Min_Maj_Min) and the last configuration had one nozzle oriented along the minor plane and two along the major plane (Maj_Min_Maj). In each case, the Reynolds number based on the maximum jet velocity and the equivalent diameter was 10,000. A planar particle image velocimetry system was used to measure the velocity field in the jet symmetry plane. The velocity decay, jet spread, merging point, combined point and potential core length were used to characterize the effects of nozzle orientation on the mixing performance. For both twin jets and triple jets, it was observed that the velocity decay rate is not sensitive to nozzle orientation. However, the spread rate was approximately 35% higher in the minor plane for each configuration. In addition, the potential core length for 3_Minor was approximately 42% shorter than Twin_Minor. Furthermore, contour plots of swirling strength, Reynolds shear stress and turbulent intensities revealed significant differences between the minor and major plane for both twin and triple jets. One-dimensional plots revealed that jets approached self-similarity at a faster rate in the major axis.
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Keywords
Turbulence, Particle image velocimetry, Turbulent jets, Axis-switching, Swirling strength, Reynolds stresses
Citation
Morris, E. M., Aleyasin, S. S., Biswas, N., and Tachie, M. F., 2020, “Turbulent Properties of Triple Elliptic Free Jets with Various Nozzle Orientation,” Journal of Fluids Engineering, 142(3)
Morris, E. M., Biswas, N., Aleyasin, S. S. and Tachie, M. F., 2019, “The Effects of Nozzle Orientation on Mixing Characteristics of Elliptic Twin Free Jets,” the ASME-JSME-KSME 2019 Joint Fluids Engineering Conference (AKLFLUIDS), AJKFLUIDS2019-5478
Morris, E. M., Aleyasin, S. S., Biswas, N. and Tachie, M. F., 2019, “Experimental Investigation of Nozzle Orientation Effects on Mixing Characteristics of Elliptic Triple Free Jets,” the ASME-JSME-KSME 2019 Joint Fluids Engineering Conference (AKLFLUIDS), AJKFLUIDS2019-5463
Morris, E. M., Biswas, N., Aleyasin, S. S. and Tachie, M. F., 2019, “The Effects of Nozzle Orientation on Mixing Characteristics of Elliptic Twin Free Jets,” the ASME-JSME-KSME 2019 Joint Fluids Engineering Conference (AKLFLUIDS), AJKFLUIDS2019-5478
Morris, E. M., Aleyasin, S. S., Biswas, N. and Tachie, M. F., 2019, “Experimental Investigation of Nozzle Orientation Effects on Mixing Characteristics of Elliptic Triple Free Jets,” the ASME-JSME-KSME 2019 Joint Fluids Engineering Conference (AKLFLUIDS), AJKFLUIDS2019-5463