Simultaneous measurements of concentration and velocity in a CO2 jet issuing into a grid turbulence by two-sensor hot-wire probe

Sakai, Yasuhiko; Watanabe, Takao; Kamohara, Satoru; Kushida, Takehiro; Nakamura, Ikuo

doi:10.1016/s0142-727x(01)00084-4

Cited by 12 publications

(16 citation statements)

References 14 publications

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“…The radial distance is normalised by b U . The profiles are similar to those obtained in regular grid turbulence (Sakai et al 2001), and they show a self-similar shape after x/d = 15. …”

Section: Characteristics Of Turbulent Jet Diffusion Fieldsupporting

confidence: 80%

“…The wind tunnel, which is identical to that used in our previous study (Sakai et al 2001), consists of a fan, diffuser, honeycomb, mesh, contraction section, test section and exhaust chamber. The cross section of the test section is 300 × 300 mm 2 .…”

Section: Experimental Apparatusmentioning

confidence: 99%

“…The output voltage E of the hot-wire probe varies according to the overheat ratio (OHR) ε R and CO 2 concentration (Sakai et al 2001;Chassaing 1977) as shown in Fig. 2.…”

Section: Dual Hot-wire Probe and Simultaneous Measurement Of Instantamentioning

confidence: 99%

“…It is possible to simultaneously measure the axial velocity and concentration of the CO 2 -air mixture using this dependency (Sakai et al 2001;Chassaing 1977Chassaing , 1979. The dual hot-wire probe (Sakai et al 2001) illustrated in Fig. 1 consists of platinum wires (each having a 5 µm diameter and 1 mm sensor length).…”

Section: Dual Hot-wire Probe and Simultaneous Measurement Of Instantamentioning

confidence: 99%

“…First, the streamwise and vertical instantaneous velocities in grid turbulence were measured using hot-wire anemometry with an X-type hot-wire probe. Then, the instantaneous axial velocity and CO 2 volume fraction concentra-tion in the jet diffusion fields were simultaneously measured using a composite probe consisting of two concentration-sensitive I-type hot-wire sensors (Sakai et al 2001). The effects of free-stream turbulence on jet diffusion fields are discussed.…”

Section: Introductionmentioning

confidence: 99%

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Scalar mixing in turbulent flows is widely observed in nature as well as in industrial plants. In this chapter, we deal with three topics related to mixing and diffusion in grid-generated turbulence. The first topic (shown in Sect. 1) is experimental research on an axisymmetric CO 2 jet issuing into free-stream turbulent flows generated by a square-mesh biplane round-rod grid (referred to as a regular grid in Sect. 1) and a square fractal grid. The CO 2 jet issues from a small pipe located in the decaying region of these grid turbulences. A composite probe consisting of two concentration-sensitive I-type hot-wire sensors is used. For both flows, the mesh Reynolds number in the free stream is 6,000, and the jet Reynolds number based on the relative velocity between the free stream and the exit velocity of the jet is 5,000. The Taylor Reynolds numbers are about 100 and 35 for the square fractal grid and the regular grid, respectively. The results show that the half-widths of the mean velocity and concentration of the jets increase more rapidly, and the root mean square velocity and concentration in the axial direction decay more slowly for stronger free-stream turbulence. The second topic (shown in Sect. 2) is the development of a mixing layer of a high-Schmidt-number passive scalar in turbulent flows generated by a square-mesh biplane square-bar grid (referred to as a regular grid in Sect. 2) and a square fractal grid with the same mesh Reynolds number of 2500. A uniform passive scalar (Rhodamine B) is supplied only from the lower stream; therefore, scalar mixing layers with an initial step profile develop downstream of the grids. Particle image velocimetry and planar laser-induced fluorescence are used to investigate the

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“…The radial distance is normalised by b U . The profiles are similar to those obtained in regular grid turbulence (Sakai et al 2001), and they show a self-similar shape after x/d = 15. …”

Section: Characteristics Of Turbulent Jet Diffusion Fieldsupporting

confidence: 80%

Section: Experimental Apparatusmentioning

confidence: 99%

“…The output voltage E of the hot-wire probe varies according to the overheat ratio (OHR) ε R and CO 2 concentration (Sakai et al 2001;Chassaing 1977) as shown in Fig. 2.…”

Section: Dual Hot-wire Probe and Simultaneous Measurement Of Instantamentioning

confidence: 99%