prof. Ing. Jan Jedelský, Ph.D.
E-mail:   jedelsky@fme.vutbr.cz  WWW:   http://ottp.fme.vutbr.cz/users/jedelsky/ Dept.:   Energy Institute Dept. of Thermodynamics and Environmental Engineering Position:   Professor Room:   A2/404 Dept.:   Energy Institute Dept. of Thermodynamics and Environmental Engineering Position:   Research Worker Room:   A2/404

Supervised courses:

• Experimental Methods II (IEE)
• Noise and Vibrations (IHV)

Publications:

• NORDLUND, M.; BĚLKA, M.; KUCZAJ, A.; LÍZAL, F.; JEDELSKÝ, J.; ELCNER, J.; JÍCHA, M.:
  Multicomponent aerosol particle deposition in a realistic cast of the human upper respiratory tract, Taylor & Francis LTD
  journal article in Web of Science
• URBÁN, A.; ZAREMBA, M.; MALÝ, M.; JÓZSA, V.; JEDELSKÝ, J.:
  Droplet dynamics and size characterization of high-velocity airblast atomization, Elsevier
  journal article in Web of Science
• ZAREMBA, M.; WEIß, L.; MALÝ, M.; WENSING, M.; JEDELSKÝ, J.; JÍCHA, M.:
  Low-pressure twin-fluid atomization: Effect of mixing process on spray formation, Elsevier
  journal article in Web of Science
• LÍZAL, F.; JEDELSKÝ, J.; JÍCHA, M.; HAPALA, R.:
  Rychlostní pole v okolí vyústky pro odmrazování a odmlžování čelního skla osobního automobilu, Society of Environmental Engineering
  journal article in Scopus
• ELCNER, J.; LÍZAL, F.; JEDELSKÝ, J.; JÍCHA, M.; CHOVANCOVÁ, M.:
  Numerical investigation of inspiratory airflow in a realistic model of the human tracheobronchial airways and a comparison with experimental results, Springer Berlin Heidelberg
  journal article in Web of Science
• JEDELSKÝ, J.; JÍCHA, M.:
  Spray characteristics and liquid distribution of multi-hole effervescent atomisers for industrial burners, Elsevier
  journal article in Web of Science
• BĚLKA, M.; LÍZAL, F.; JEDELSKÝ, J.; ŠTARHA, P.; DRUCKMÜLLEROVÁ, H.; JÍCHA, M.:
  Application of image analysis method to detection and counting of glass fibers from filter samples, Taylor and Francis
  journal article in Web of Science
• MLKVIK, M.; ZAREMBA, M.; STÄHLE, P.; SCHUCHMANN, H.; GAUKEL, V.; JEDELSKÝ, J.:
  Influence of the primary breakup conditions on the droplet size of the spray generated by twin fluid atomizers,
  Applied Mechanics and Materials, Vol.821, (2016), No.1, pp.91-96, ISSN 1662-7482, Trans Tech Publications Inc.
  journal article - other
  akce: Engineering Mechanics 2015, Svratka, 11.05.2015-14.05.2015
• LÍZAL, F.; BĚLKA, M.; ADAM, J.; JEDELSKÝ, J.; JÍCHA, M.:
  A method for in vitro regional aerosol deposition measurement in a model of the human tracheobronchial tree by the positron emission tomography, SAGE Publications
  journal article in Web of Science
• ZAREMBA, M.; MALÝ, M.; MLKVIK, M.; JEDELSKÝ, J.; JÍCHA, M.:
  Droplet dynamics in sprays generated by four different twin-fluid atomizers,
  Turbulence, Heat and Mass Transfer 8, pp.649-652, ISBN 978-1-56700-427-4, (2015), Begel House Inc.
  conference paper
  akce: 8th International Symposium on Turbulence, Heat and Mass Transfer, Sarajevo, 15.09.2015-18.09.2015
• MLKVIK, M.; STÄHLE, P.; SCHUCHMANN, H.; GAUKEL, V.; JEDELSKÝ, J.; JÍCHA, M.:
  Twin-fluid atomization of viscous liquids: The effect of atomizer construction on breakup process, spray stability and droplet size, Elsevier
  journal article in Web of Science
• JEDELSKÝ, J.; JÍCHA, M.:
  Energy considerations in spraying process of a spill-return pressure-swirl atomizer, Elsevier
  journal article in Web of Science
• ĎURDINA, L.; JEDELSKÝ, J.; JÍCHA, M.:
  Investigation and comparison of spray characteristics of pressure-swirl atomizers for a small-sized aircraft turbine engine, Elsevier
  journal article in Web of Science
• LEŽOVIČ, T.; LÍZAL, F.; JEDELSKÝ, J.; JÍCHA, M.:
  HVAC automotive vents evaluation and their performance, Taylor & Francis
  journal article in Web of Science
• JEDELSKÝ, J.; JÍCHA, M.:
  Energy conversion during effervescent atomization, Elsevier
  journal article in Web of Science
• JEDELSKÝ, J.; JÍCHA, M.:
  Spatially and Temporally Resolved Distributions of Liquid in an Effervescent Spray, Begell House
  journal article in Web of Science
• JEDELSKÝ, J.; JÍCHA, M.:
  Energy Conversion in Effervescent Atomization,
  proceedings of 12th International Conference on Liquid Atomization and Spray Systems, pp.1-8, ISBN 978-88-903712-1-9, (2012), Heidelberg University
  conference paper
  akce: 12th International Conference on Liquid Atomization and Spray Systems, Heidelberg, 02.09.2012-06.09.2012
• JEDELSKÝ, J.; LÍZAL, F.; JÍCHA, M.:
  Characteristics of Turbulent Particle Transport in Human Airways under Steady and Cyclic Flows, Elsevier
  journal article in Web of Science
  akce: Seventh International Symposium on Turbulence and Shear Flow Phenomena, Ottawa, 28.07.2011-31.07.2011
• LÍZAL, F.; ELCNER, J.; HOPKE, P.; JEDELSKÝ, J.; JÍCHA, M.:
  Development of a realistic human airway model, SAGE PUBLICATIONS LTD
  journal article in Web of Science
• JEDELSKÝ, J.; JÍCHA, M.:
  Unsteadiness in Effervescent Sprays: a New Evaluation Method and the Influence of Operational Conditions, Begell House
  journal article in Web of Science

List of publications at Portal BUT

Abstracts of most important papers:

• JEDELSKÝ, J.; JÍCHA, M.:
  Energy considerations in spraying process of a spill-return pressure-swirl atomizer, Elsevier
  journal article in Web of Science
  The work focuses on energy conversion during the internal flow, discharge and formation of the spray from a pressure-swirl (PS) atomizer in the simplex as well as spill-return mode. Individual energy forms are described in general and assessed experimentally for a particular PS atomizer and light heating oil as a medium. The PS spray was observed at various loads to investigate the liquid breakup process and the spray characteristics. Spatially resolved diameters and droplet velocities, measured by means of phase-Doppler anemometry, served for estimation of the energy characteristics in the PS spray. The input energy given by the potential energy of the supplied liquid partially converts into the kinetic energy (KE) in the swirling ports with hydraulic loss in per cent scale. Most of the pressure drop is associated with rotational motion in the swirl chamber with total conversion efficiency at the exit orifice 58%. The rest of the input energy ends up as friction loss, leaving room for improvement. The overall value (ID32) of the Sauter mean diameter of droplets in the spray, D32, varies with pressure drop dpl powered to –0.1. The radial profiles of D32 widen with the increase in spill/feed ratio (SFR), but the ID32 remain almost constant within the studied SFR range. The spray KE at closed spill line covers the droplet KE (21–26%) and that of entrained air (10–13%), both moderately varying with dpl. The specific KEs of both the liquid and air markedly drop down with the spill line opening. Atomization efficiency is less than 0.3% for the studied range of operation regimes and depends on dpl and SFR. Our results confirm low power demand of simplex PS atomizers, with extra energy consumption in spill mode. Several recommendations are given for PS atomizer innovations and development of new, more efficient, designs meeting more stringent environmental requirements.
• JEDELSKÝ, J.; JÍCHA, M.:
  Spatially and Temporally Resolved Distributions of Liquid in an Effervescent Spray, Begell House
  journal article in Web of Science
  We employed Planar Laser-Induced Fluorescence (LIF) in combination with stereoscopic Particle Image Velocimetry for imaging of concentration and flux fields of liquid phase in an effervescent spray. Light heating oil (LHO) was continuously atomized with aid of pressurised air. The atomizer was operated at atomizing pressures of 0.1 – 0.5 MPa and Gas–to–Liquid–Ratio by mass (GLR) of 2 – 50%. Basic spectral and time-resolved LIF characteristics of natural fluorescence of LHO, used for LIF based concentration measurements, are detailed. Instant distributions of concentration and flux were processed into time-average radial profiles and into radial profiles of normalised root–mean–square (rms) fluctuations. Time-average concentration profiles are bell shaped with maximum concentration at the spray centreline and exponential decrease with radial distance. Liquid concentration based half-angles vary with operation conditions between 7.9 and 12.2 deg. GLR causes narrowing of the spray angle while inlet pressure has an indistinctive effect. Time-average flux profiles resemble the concentration profiles but are narrower, with half-angles of 4.6 – 6.4 deg. Radial profiles of rms fluctuations of concentration (and also flux) generally show low value near the spray axis, increase with increasing radial distance and maximum close to the spray edge. Overall values of the rms fluctuations are used as a measure of spray unsteadiness and correlated with internal two-phase flow patterns predicted by a published flow map. The spray unsteadiness is relatively low when operated in annular flow regime and increases with change to bubbly flow regime. It confirms a direct link between the spray and internal flow.
• JEDELSKÝ, J.; LÍZAL, F.; JÍCHA, M.:
  Characteristics of Turbulent Particle Transport in Human Airways under Steady and Cyclic Flows, Elsevier
  journal article in Web of Science
  akce: Seventh International Symposium on Turbulence and Shear Flow Phenomena, Ottawa, 28.07.2011-31.07.2011
  Motion of monodispersed micron-sized particles suspended in air flow was studied on transparent model of human airways using Phase-Doppler Particle Analyser (P/DPA). Time-resolved velocity data for particles in size range 1 to 8 um were processed using Fuzzy Slotting Technique embedded in Kern software (Nobach, 2002) to estimate power spectral density (PSD) of velocity fluctuations. Optimum setup of the software for these data was found and recommendations for improvements of future experiments were given. Typical PSD plots are documented and mainly differences among (1) steady-flow regimes and analogous cyclic breathing regimes, (2) inspiration and expiration breathing phase and (3) behaviour of particles with different size are described for several different positions in the airway model. Systematically higher content of velocity fluctuations in the upper part of frequency range (30 to 500 Hz) was found for cyclic flows in comparison with corresponding steady flows. Expiratory flows in both the (steady and cyclic) cases produce more high-frequency fluctuations compared to inspiratory flows. Negligible differences were found for flow of particles in the inspected size range 1 to 8 um at frequencies up to 500 Hz. This finding was explained by Stokes number analysis. Implied match of the air and particle flows thereby confirms a possibility to use the P/DPA data as air flow velocity estimate.
• JEDELSKÝ, J.; JÍCHA, M.:
  Unsteadiness in Effervescent Sprays: a New Evaluation Method and the Influence of Operational Conditions, Begell House
  journal article in Web of Science
  A new evaluation method of unsteadiness of the spray generated by an effervescent atomizer is presented. The method is based on measurements of pressure fluctuations in the atomizer mixing chamber. Measurements, made under different atomizer operational conditions, show that the spray unsteadiness depends mainly on gas-to-liquid ratio (GLR). Decrease in GLR causes the spray to become more unsteady. The relation between atomizer internal two-phase flow pattern and the spray unsteadiness is elucidated by visualization of the internal two-phase flow using a digital camera and the use of published two-phase flow maps. Findings of the new method are complemented and confronted with the results obtained by the use of the spray unsteadiness evaluation method of Edwards and Marx.