The discharge coefficient of effervescent atomizers

Ochowiak, Marek; Broniarz-Press, L.; Różański, Jacek

doi:10.1016/j.expthermflusci.2010.06.003

Cited by 16 publications

(10 citation statements)

References 9 publications

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“…The CF2 exhibits a systematically higher Cd compared to CF1. The increasing exit orifice diameter tends to reduce the Cd values, which is comparable with effervescent atomizers where Cd increases with decreasing GLR and also with decreasing exit orifice [6].…”

Section: Resultsmentioning

confidence: 61%

Counter flow atomizer: Effect of the area ratio of the outlet orifice and the inlet air canal

Smutková,

Malý,

Cejpek

et al. 2022

EPJ Web Conf.

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The need to reduce the energy demand of processes also creates pressure to make atomizers more efficient. A promising development path could be counterflow atomizers (CFA). An atomizer, or synonymously a nozzle, is a device that turns a liquid into a spray. The CFA is a twin-fluid type of atomizer because both the liquid and the atomizing gas are fed into it. Initial results suggest that CFA is capable of the same quality of atomization but using half the air mass flow rate compared to conventional twin-fluids atomizers when operated at identical inlet pressure. This means half the energy requirements with the same efficiency. This atomizer also shows a great promise in the atomization of highly viscous substances such as waste-based fuels and biomass oils. In CFA, the air expands twice; first, at the discharge from the air inlet canal into the mixing tube, and second, at the discharge from the atomizer to the surrounding atmosphere. Therefore, one of the main control parameters is the area ratio of the exit orifice and the air inlet canal. This study experimentally investigates the effect of this ratio on the spray quality for two different CFA atomizers using Phase Doppler Anemometry (PDA), which provides the velocity and size of individual droplet in the spray. The atomizers were operated at the air inlet pressure of 100 and 200 kPa and gas-to-liquid mass (GLR) ratios of 5, 10 and 20%. The effect of the double expansion can be well observed in the pressure differences between the air inlet and the pressure inside the mixing tube. The length of the air counterflow insert had a significant effect on the atomizer performance. For the shorter counterflow channel, a minimal effect on flow was observed; this atomizer behaved like a conventional twin-fluid atomizer and all expansions occurred downstream of the exit orifice. The longer counterflow canal changed the internal expansion ratios, larger droplets, wider spray and higher discharge coefficients (Cd) were obtained.

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Section: Resultsmentioning

confidence: 61%

Counter flow atomizer: Effect of the area ratio of the outlet orifice and the inlet air canal

Smutková,

Malý,

Cejpek

et al. 2022

EPJ Web Conf.

View full text Add to dashboard Cite

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“…where U L is the cross-sectional average velocity of the liquid phase. C D depends on Re L in a linear manner [24,35,57], as confirmed in Figure 8a. The value of Re L drops with rising liquid viscosity at constant GLRs (Figure 8b).…”

Section: The Effect Of Liquid Viscosity On C Dmentioning

confidence: 74%

“…The literature review revealed that C D is affected by working conditions [26], the exit office size and geometry [28,35], and the physical properties of the phases [24,28]. Here a general function applies:…”

Section: Methodology Of Data Analysismentioning

confidence: 99%

“…The IOG nozzle ( Figure 2c) has been frequently investigated as well [5,24,28,35,45,46]. In this configuration, the liquid flows inside the main chamber, while the gas enters into the aerator tube and bubbles outward to mix with the liquid.…”

Section: Tested Nozzlesmentioning

confidence: 99%

“…To study the effect of the internal-mixing method factor, for the first attempt, five types of IMTF nozzles with widely different internal-mixing methods were tested under the same conditions, liquid types, and orifice geometry. Two of the selected nozzles (outside-in-gas (OIG (and inside-out-gas (IOG)) are well-known and frequently used [1,5,10,13,24,28,[30][31][32][33][34][35][36]. The following two designs (outside-in-liquid (OIL) and air-core-liquid-ring (ACLR)) were introduced recently; they are promising due to a better atomization performance [10,30,31,34], [37,38].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The Effect of Geometrical, Operational, Mixing Methods, and Rheological Parameters on Discharge Coefficients of Internal-Mixing Twin-Fluid Atomizers

et al. 2020

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Accurate prediction of the discharge coefficient (CD) for internal-mixing twin-fluid (IMTF) atomizers is challenging, the effect of control factors remains inadequately understood, and comparative data on the CD of IMTF atomizers are unavailable. This work presents an experimental study on CD for different IMTF atomizers with a wide range of factors, including the gas-to-liquid ratio (GLR), the inlet-overpressure ratio (∆pmix/pamb), the orifice length-to-diameter ratio (Lo/do), and the liquid viscosity (µL). Five atomizers with different internal-mixing principles were probed on a cold test rig, including the frequently studied outside-in-gas (OIG) and inside-out-gas (IOG) effervescent types, the recently-introduced outside-in-liquid (OIL) and air-core-liquid-ring (ACLR) atomizers, and our new design named the swirling-air-core-liquid-ring (SACLR) atomizer. The results demonstrate that CD is governed mainly by GLR, and reduces if GLR, Lo/do, or µL is increased. An increase in ∆pmix/pamb causes a CD reduction up to ∆pmix/pamb = 0.98, and CD increases for a higher ∆pmix/pamb. Surprisingly, differences in CD amid examined atomizers were found negligible, although the flow visualization inside the orifice showed a significantly different flow character for each one of the atomizers. Finally, a general CD correlation fitting with an R2 ≥0.99 for all the tested nozzles was proposed. The results amend the present knowledge, allow design optimization, and provide flow rate prediction for a variety of IMTF atomizers.

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Analysis of Liquid Jet Breakup in One‐ and Two‐Phase Flows

2012

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The phenomenon of breakup of a jet into drops has been applied mainly to separation technologies in the chemical, pharmaceutical, and metallurgical industries. The paper deals with the experimental analysis directed at the breakup of polymer solutions flowing through an orifice nozzle. The analysis of the breakup and atomization of a liquid jet by a high‐speed gas jet is presented. Additionally, non‐Newtonian effects on the breakup of the liquid jet into drops were studied using the microphotography method. In the experiments, various aqueous solutions of polyacrylamide were used. The polymer solutions studied were power‐law fluids. Analysis of the photographs of the jet breakup showed that the length of the jets depends on the liquid and gas flow rates and on the concentration of the polymer used. High‐molecular‐weight polymers added to a solvent lead to changes in the rheological properties of the liquid and the breakup length of the jet.

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The discharge coefficient of effervescent atomizers

Cited by 16 publications

References 9 publications

Counter flow atomizer: Effect of the area ratio of the outlet orifice and the inlet air canal

Counter flow atomizer: Effect of the area ratio of the outlet orifice and the inlet air canal

The Effect of Geometrical, Operational, Mixing Methods, and Rheological Parameters on Discharge Coefficients of Internal-Mixing Twin-Fluid Atomizers

Analysis of Liquid Jet Breakup in One‐ and Two‐Phase Flows

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