Analysis of effervescent spray quality for oil-fired furnace application

Hájek, Jiří; Dohnal, Mirko; Vondál, Jiří; Broukal, J.

doi:10.1007/s10098-015-0922-0

Cited by 2 publications

(4 citation statements)

References 22 publications

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“…The gas core diameter was used to measure the time variation of the gas phase inside the exit orifice, which corresponds with the internal flow regime [51,52]. Additionally, this diameter can be used to indicate some parameters for the gas-liquid flow (i.e., the gas void fraction and the corresponding slip ratio), as represented by Equations (5)- (8).…”

Section: Methodology Of Data Analysismentioning

confidence: 99%

“…Processes 2020, 8, x FOR PEER REVIEW 9 of 22 the gas-liquid flow (i.e., the gas void fraction and the corresponding slip ratio), as represented by Equations (5)- (8).…”

Section: Methodology Of Data Analysismentioning

confidence: 99%

“…Twin-fluid (TF) atomizers were found to be more advantageous over other liquid atomization devices in numerous applications including gas turbines [1][2][3], scramjet [4], internal combustion engines [5,6], furnaces, and boilers [7][8][9]. They have been used for spray drying in the food industry [10][11][12][13][14][15], humidification, dust control, gas cooling, spray coating [16], pharmaceutical or consumer products [17], and water mist fire suppression systems [18].…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Methodology Of Data Analysismentioning

confidence: 99%

“…Processes 2020, 8, x FOR PEER REVIEW 9 of 22 the gas-liquid flow (i.e., the gas void fraction and the corresponding slip ratio), as represented by Equations (5)- (8).…”

Section: Methodology Of Data Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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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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“…The effervescent atomizers can deal with wide range of liquids due to its insensitivity to the liquid physical properties, simple design and nearly no maintenance requirements [3], produce low pollutant emissions when used in combustion systems due to the presence of air (atomizing gas) in the spray core [3]- [11]. These advantages enabled the effervescent atomizers to be utilized in many applications, including gas turbine combustors [12]- [14], scramjet engines [4], IC engines [15]- [17], furnaces and boilers [18]- [20], also used in humidification, dust control, gas cooling, spray coating processes [8], spray drying (or spray crystallization) in food industry [21] [22], pharmaceutical, and consumer products [23].…”

Section: Introductionmentioning

confidence: 99%

Experimental Investigation of the Effect of the Internal Two-Phase Flow and the Bubble Size on the Effervescent Spray Characteristics

2016

ERJ. Engineering Research Journal

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Reducing the pressurized atomizing gas in the effervescent atomizers with keeping fine spray is a desirable aim. This experimental study focuses on improving the characteristics of the effervescent spray (i.e. drop size and spray cone angle); while an "in-out" gas injection configuration atomizer operates under low gas-to-liquid ratios (GLR). These important characteristics are mainly affected by the internal two-phase flow pattern. Wherefore, shadowgraphy is utilized for visualizing and investigating the internal two-phase flow pattern directly upstream the exit orifice. The atomizer is operated at air gauge pressure of 0.6 Mpa and GLRs of (0.71%-5.74%). For controlling the internal flow at the operating GLRs, two novel bubble breakers (BB) are designed and tested. The bubble breakers are fixed in the mixing chamber to affect the bubble size. The shadowgraph technique is utilized for visualizing and quantifying bubbles inside the atomizer, spray characteristics and the near nozzle spray. From the visualization and results, the internal two-phase flow patterns inside the mixing chamber vary from bubbly flow at the lowest three GLRs to a bubble-annular flow at the largest GLR, passing through an unsteady transition stage between these two patterns. Also, it is observed that the bubble breakers efficiently disintegrate large bubbles; the largest reduction percentage in the bubble size is 75.63% for the case of flat end BB at GLR of 2.21%. Also, the results showed that the drop size and spray cone angle are strongly affected by the bubble size (i.e. the internal flow structure) subsequently the presence of the bubble breakers. The largest reduction percentage in the droplet size is 68.88% for the case of the cone end BB at GLR of 0.77% and the largest increment percentage in the spray cone angle is 69.97% for the cone end BB at GLR of 0.77 %, all relative to the case of without BB.

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Analysis of effervescent spray quality for oil-fired furnace application

Cited by 2 publications

References 22 publications

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

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

Experimental Investigation of the Effect of the Internal Two-Phase Flow and the Bubble Size on the Effervescent Spray Characteristics

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