Abstract
A flow mixing nozzle can produce satisfactory atomization for heavy oil. However, the study of the internal flow pattern of this nozzle, along with the spray morphology and its transformation, is currently limited to a low flow rate for the two-phase inlet. A flow mixing nozzle with a moderate inlet flow rate and various nozzle structures (H/D) was experimentally studied using a self-designed flow mixing nozzle and a self- constructed experimental platform, as described in this paper. The results demonstrate that at a moderate two-phase inlet flow rate, a clear cone is observed inside the nozzle that can be described by the cone angle and the dimensionless cone area. In short, as air inlet flow rate increases, the cone volume decreases, the jet atomization effect is enhanced, the distribution range narrows, the flow pattern changes to flow blurring, and the variation trend is the opposite of that when the water inlet flow rate is increased. An analysis of the experimental results demonstrate that the flow pattern and spray morphology of the flow mixing nozzle under a moderate inlet flow rate are determined by the inertial force of air and the inertial force and surface tension force of water. When the air flow rate is increased, the inertial force is enhanced, and the cone radial concavity is strengthened; or, the cone disappears. At this time, the spray morphology is mainly expressed as atomization. When the water flow rate increases, the water inertial force increases, and the cone changes to a radial protrusion. The spray morphology is mainly expressed as a jet or breakup.
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References
Ganan-Calvo AM (1998) Generation of steady liquid microthreads and micron-sized monodisperse sprays in gas streams. Phys Rev Lett 80(2):285–288
Ganan-Calvo AM (2005) Enhanced liquid atomization: from flow-focusing to flow-blurring. Appl Phys Lett 86(21):4601
Ganan-Calvo AM et al (2007) Focusing capillary jets close to the continuum limit. Nat Phys 3(10):737–742
Ting S (2009) Experimental and theoretical investigation on flow focusing. University of science and technology of china, Hefei
Yang L et al (2015) Formation mechanism of the micro droplet based on the flow focusing structure. Micronanoelectron Technol 52(9):576–580
Liu ZM, Yang Y (2016) Influence of geometry configurations on the microdroplets in flow focusing microfluidics. Chin J Theor Appl Mech 48(4):867–876
Acero AJ et al (2013) A new flow focusing technique to produce very thin jets. J Micromech Microeng 23(6):1063–1076
Acero AJ et al (2012) Enhancement of the stability of the flow focusing technique for low-viscosity liquids. J Micromech Microeng 22:1–6
Vega EJ et al (2013) A novel technique for producing metallic microjets and microdrops. Microfluid Nanofluid 14(1–2):101–111
Montanero JM et al (2010) Micrometer glass nozzles for flow focusing. J Micromech Microeng 20(7):075035
Rosellllompart J, Ganan-Calvo AM (2008) Turbulence in pneumatic flow focusing and flow blurring regimes. Phys Rev E Stat Nonlinear Soft Matter Phys 77(3Pt2):036321
Jiang LL, Agrawal AK (2014) Investigation of glycerol atomization in the near-field of a flow-blurring injector using time-resolved PIV and high-speed visualization. In: IEEE international conference on neural networks, pp. 323–338
Jiang LL (2014) Investigation of atomization mechanisms and flame structure of a twin-fluid injector for different liquid fuels. The University of Alabama, Tuscaloosa
Simmons BM, Agrawal AK (2012) Flow blurring atomization for low-emission combustion of liquid biofuels. Combust Sci Technol 184(5):660–675
Panchasara HV, Sequera D, Schreiber W, Agrawal AK (2009) Emissions reductions in diesel and kerosene flames using a novel fuel injector. J Propuls Power 25(4):984–987
De Azevedo CG, Andrade JCD, Costa FDS (2012) Characterization of a blurry injector for burning biofuels in a compact flameless combustion chamber. In: 14th Brazilian congress of thermal sciences and engineering, Rio de Janeiro, Brazil
De Azevedo CG, Costa FDS, Andrade JCD (2013) Effects of nozzle exit geometry on spray characteristics of a blurry injector. At Sprays 23(3):193–209
Azevedo CGD, Andrade JCD, Costa FDS (2016) Effects of injector tip design on the spray characteristics of soy methyl ester biodiesel in a blurry injector. Renew Energy 85:287–294
Pongvuthithum R, Moran J, Sankui T (2018) A flow blurring nozzle design for combustion in a closed system. Appl Therm Eng 131:587–594
Costa ALR, Gomes A, Cunha RL (2017) Studies of droplets formation regime and actual flow rate of liquid-liquid flows in flow-focusing microfluidic devices. Exp Therm Fluid Sci 85:167–175
Acknowledgements
This study was funded by the National Natural Science Foundation of China (Grant Nos. 51776016, 51606006), Beijing Natural Science Foundation (Grant Nos. 3172025, 3182030), National Key Research and Development Program (Grant No. 2017YFB0103401), National Engineering Laboratory for Mobile Source Emission Control Technology (Grant No. NELMS2017A10), and the Talents Foundation of Beijing Jiaotong University (Grant No. 2018RC017).
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Zhao, J., Ning, Z. & Lv, M. Experimental study on the two-phase flow pattern and transformation characteristics of a flow mixing nozzle under a moderate flow rate. Meccanica 54, 1121–1133 (2019). https://doi.org/10.1007/s11012-019-01014-2
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DOI: https://doi.org/10.1007/s11012-019-01014-2