prof. Ing. Miroslav Jícha, CSc.
E-mail:   jicha@fme.vutbr.cz  Dept.:   Energy Institute Dept. of Thermodynamics and Environmental Engineering Position:   Professor Room:   A2/405

Supervised courses:

• Heat and Mass Transfer (9PTL)
• Heat and Mass Transfer (IPT-A)
• Heat and Mass Transfer (9PTL-A)

Publications:

• FOJTLÍN, M.; FIŠER, J.; POKORNÝ, J.; POVALAČ, A.; URBANEC, T.; JÍCHA, M.:
  An Innovative HVAC Control System: Implementation and testing in a vehicular Cabin
  journal article in Web of Science
• BAJKO, J.; NIEDOBA, P.; ČERMÁK, L.; JÍCHA, M.:
  Stabilization of a meshless method via weighted least squares filtering, Elsevier B.V.
  journal article in Web of Science
• TUHOVČÁK, J.; HEJČÍK, J.; JÍCHA, M.:
  Comparison of heat transfer models for reciprocating compressor, Elsevier
  journal article in Web of Science
• FOJTLÍN, M.; FIŠER, J.; JÍCHA, M.:
  Determination of convective and radiative heat transfer coefficients using 34-zones thermal manikin: Uncertainty and reproducibility evaluation, Elsevier Inc.
  journal article in Web of Science
• 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
• POKORNÝ, J.; FIŠER, J.; JÍCHA, M.:
  Virtual Testing Stand for evaluation of car cabin indoor environment, Elsevier
  journal article in Web of Science
• FIŠER, J.; JÍCHA, M.:
  Impact of air distribution system on quality of ventilation in small aircraft cabin, Elsevier
  journal article in Web of Science
• POSPÍŠIL, J.; JÍCHA, M.:
  Particle re-suspension in street canyon with two-way traffic, Inderscience Enterprises Limited
  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.
• BAJKO, J.; ČERMÁK, L.; JÍCHA, M.:
  High order finite point method for the solution to the sound propagation problems, Elsevier
  journal article in Web of Science
  In this paper we present an accuracy improvement of the meshfree Finite point method. This high-order method has been used to solve the sound propagation problems, which can be modelled by linearized Euler equations. High accuracy has been obtained using polynomial reconstruction of variables involved in the Riemann solver. The order of the meshfree method will be verified on 2D acoustic pulse problem which serves as a benchmark problem with known analytical solution.
• POKORNÝ, J.; FIŠER, J.; JÍCHA, M.:
  Virtual Testing Stand for evaluation of car cabin indoor environment, Elsevier
  journal article in Web of Science
  In the paper the authors refer to a new computational tool for the transient prediction of the car cabin environment and heat load during real operating conditions. The aim of the Virtual Testing Stand software is to support an early stage of the HVAC design process to predict demands for the heating and cooling for various operational conditions and types of car. This software was developed in Matlab as a standalone executable application including a parametric generator of car cabin geometry, a heat transfer model and a graphical user interface. The mathematical model is formed by the set of heat balance equations, which takes into account the heat accumulation, and the heat exchange between the car cabin, the outside environment, the HVAC system and the passengers. In this paper the main features of Matlab application are presented together with a selected sensitivity study of two significant parameters in a winter test case.
• KNOTEK, S.; JÍCHA, M.:
  Thick liquid film instability model using CFD simulations,
  Engineering Mechanics, Vol.20, (2013), No.3/4, pp.247-254, ISSN 1802-1484
  journal article - other
  The article presents a liquid film instability model designed using results of the set of CFD simulations. The governing equations of the model are derived using a linear equation of motion. The stability analysis is carried out by imposing a liquid surface disturbance which growth rate is investigated in dependence on the geometrical and physical configuration. The gas effect parameters, which are decisive variables in the model, are derived using results of the set of CFD simulations of turbulent flow in channel with wavy surface. The agreement between predicted and measured critical gas velocities and wavelengths in dependence on the liquid film thickness is very good.
• FIŠER, J.; JÍCHA, M.:
  Impact of air distribution system on quality of ventilation in small aircraft cabin, Elsevier
  journal article in Web of Science
  A ventilation system of sufficient performance is the basic condition for comfort and health risk free environment in enclosed aircraft cabin spaces. The airflow pattern and spreading of fresh air into the cabin space mainly depend on the type of the air distribution system and location of heat sources/sinks. The present study deals with the investigation of the dependency between the type of the air distribution system and indoor air quality in a cabin of a small transport aircraft. The mock-up interior geometry of a small aircraft cabin for nine passengers was adopted for the investigation. Three types of the air distribution system were investigated: a typical mixing ventilation system, a modified mixing ventilation system and an under-aisle displacement ventilation system. The quality of ventilation was assessed based on the local mean age of air using CFD software Star-CCM+. At first, the CFD model of a typical mixing ventilation was validated against the experimental data of airflow in the mock-up of the small aircraft cabin. The validated model was then used for the evaluation of the three distribution systems under cold, mild and hot ambient environment conditions from the point of their performance for several typical aircraft operational conditions. Results of the study show a strong dependence of the air distribution systems performance on the ambient conditions. The most stable air distribution was reached with the modified mixing air distribution system. Other types of ventilation systems failed to provide sufficient ventilation and cooling under hot ambient conditions.