EXP 1-1 Description: Difference between revisions
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= | =Pressure-swirl spray in a low-turbulence cross-flow= | ||
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= Description of Study Test Case = | = Description of Study Test Case = | ||
The conical liquid sheet produced by water spraying from a PSA was investigated in cross-flow of non-heated, non-pressurised air. See '''[https://kbwiki.ercoftac.org/w/index.php/ | The conical liquid sheet produced by water spraying from a PSA was investigated in cross-flow of non-heated, non-pressurised air. See '''[https://kbwiki.ercoftac.org/w/index.php/EXP_1-1#figure1 Figure 1b]''', which shows the atomizer in the test section. The atomizer was operated continuously in cold-flow (non-reacting) conditions. It generated a water spray at inlet pressure, <math>p_{\text {in}}</math>, of 0.5 MPa. The flow conditions of the atomizer are described by Reynolds number: <br/> <br/> | ||
<div id="eqn14"> | <div id="eqn14"> | ||
{{NumBlk|:|<math> | {{NumBlk|:|<math> | ||
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where <math>\rho_l</math> is the liquid density, <math>u_{\text {in}}=Q_{\text {l}}/A_{\text {in}}</math> is the liquid velocity at inlet ports and <math>D_{\text {in}}=\sqrt{4A_{\text {in}}/\pi}</math> is the hydraulic diameter of the inlet ports (for atomizer details see '''[https://kbwiki.ercoftac.org/w/index.php/ | where <math>\rho_l</math> is the liquid density, <math>u_{\text {in}}=Q_{\text {l}}/A_{\text {in}}</math> is the liquid velocity at inlet ports and <math>D_{\text {in}}=\sqrt{4A_{\text {in}}/\pi}</math> is the hydraulic diameter of the inlet ports (for atomizer details see '''[https://kbwiki.ercoftac.org/w/index.php/EXP_1-1_Experimental_Set_Up#figure7 Figure 7]''' and corresponding text in section ''[[EXP_1-1__Experimental_Set_Up|Experimental Set Up]]''). The <math>R e_{\text {in}}=1330</math>. The presented case is one of three inlet pressure cases (<math>p_{\text {in }}= \mathrm 0.25, 0.5, 1 </math> <math> \mathrm {MPa} </math>) measured and studied in <ref name="Cejpek2"> O. Cejpek, M. Maly, J. Slama, M. M. Avulapati, and J. Jedelsky, Continuum Mechanics and Thermodynamics 34 (6), 1497 (2022) </ref>. | ||
The interaction of the spray with the cross-flowing air is controlled by the ratio of the momentum of liquid to the air momentum, <math>q</math> (see '''[https://kbwiki.ercoftac.org/w/index.php/ | The interaction of the spray with the cross-flowing air is controlled by the ratio of the momentum of liquid to the air momentum, <math>q</math> (see '''[https://kbwiki.ercoftac.org/w/index.php/EXP_1-1_Introduction#math_10 Equation 10]''') and by the Weber number which relies on the surface tension forces of the liquid film with the drag forces of the airflow, <math>We_a</math> ('''[https://kbwiki.ercoftac.org/w/index.php/EXP_1-1_Introduction#math_11 Equation 11]''') or <math>We_r</math> ('''[https://kbwiki.ercoftac.org/w/index.php/EXP_1-1_Introduction#math_12 Equation 12]'''). <math>We</math> and <math>q</math> values for the experimental regimes are given in '''[[#table2|Table 2]]'''. | ||
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! <br /><math>u_{cf}</math> [m/s] | ! <br /><math>u_{cf}</math> [m/s] | ||
! <br /><math>p_{in}</math> [MPa] | ! <br /><math>p_{in}</math> [MPa] | ||
! <br /><math>Q_{l}</math> [ | ! <br /><math>Q_{l}</math> [L/hour] | ||
! <br /><math>C_{D}</math> [–] | ! <br /><math>C_{D}</math> [–] | ||
! <br /><math>We_{a}</math> [–] | ! <br /><math>We_{a}</math> [–] | ||
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Latest revision as of 08:22, 17 August 2023
Pressure-swirl spray in a low-turbulence cross-flow
Description of Study Test Case
The conical liquid sheet produced by water spraying from a PSA was investigated in cross-flow of non-heated, non-pressurised air. See Figure 1b, which shows the atomizer in the test section. The atomizer was operated continuously in cold-flow (non-reacting) conditions. It generated a water spray at inlet pressure, , of 0.5 MPa. The flow conditions of the atomizer are described by Reynolds number:
-
(14)
where is the liquid density, is the liquid velocity at inlet ports and is the hydraulic diameter of the inlet ports (for atomizer details see Figure 7 and corresponding text in section Experimental Set Up). The . The presented case is one of three inlet pressure cases ( ) measured and studied in [1].
The interaction of the spray with the cross-flowing air is controlled by the ratio of the momentum of liquid to the air momentum, (see Equation 10) and by the Weber number which relies on the surface tension forces of the liquid film with the drag forces of the airflow, (Equation 11) or (Equation 12). and values for the experimental regimes are given in Table 2.
[m/s] |
[MPa] |
[L/hour] |
[–] |
[–] |
[–] |
[–] |
|---|---|---|---|---|---|---|
0 |
0.508 |
6.71 |
0.44 |
0.0 |
0.5 |
∞ |
8 |
0.498 |
6.72 |
0.43 |
0.5 |
0.85 |
3642.0 |
16 |
0.491 |
6.68 |
0.42 |
1.8 |
1.5 |
938.8 |
32 |
0.493 |
6.69 |
0.43 |
7.1 |
3.4 |
227.1 |
References
- ↑ O. Cejpek, M. Maly, J. Slama, M. M. Avulapati, and J. Jedelsky, Continuum Mechanics and Thermodynamics 34 (6), 1497 (2022)
Contributed by: Ondrej Cejpek, Milan Maly, Ondrej Hajek, Jan Jedelsky — Brno University of Technology
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